!------------------------------------------------------------------------------- module module_gfs_funcphys !$$$ Module Documentation Block ! ! Module: funcphys API for basic thermodynamic physics ! Author: Iredell Org: W/NX23 Date: 1999-03-01 ! ! Abstract: This module provides an Application Program Interface ! for computing basic thermodynamic physics functions, in particular ! (1) saturation vapor pressure as a function of temperature, ! (2) dewpoint temperature as a function of vapor pressure, ! (3) equivalent potential temperature as a function of temperature ! and scaled pressure to the kappa power, ! (4) temperature and specific humidity along a moist adiabat ! as functions of equivalent potential temperature and ! scaled pressure to the kappa power, ! (5) scaled pressure to the kappa power as a function of pressure, and ! (6) temperature at the lifting condensation level as a function ! of temperature and dewpoint depression. ! The entry points required to set up lookup tables start with a "g". ! All the other entry points are functions starting with an "f" or ! are subroutines starting with an "s". These other functions and ! subroutines are elemental; that is, they return a scalar if they ! are passed only scalars, but they return an array if they are passed ! an array. These other functions and subroutines can be inlined, too. ! ! Program History Log: ! 1999-03-01 Mark Iredell ! 1999-10-15 Mark Iredell SI unit for pressure (Pascals) ! 2001-02-26 Mark Iredell Ice phase changes of Hong and Moorthi ! ! Public Variables: ! krealfp Integer parameter kind or length of reals (=kind_phys) ! ! Public Subprograms: ! gpvsl Compute saturation vapor pressure over liquid table ! ! fpvsl Elementally compute saturation vapor pressure over liquid ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvslq Elementally compute saturation vapor pressure over liquid ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvslx Elementally compute saturation vapor pressure over liquid ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! gpvsi Compute saturation vapor pressure over ice table ! ! fpvsi Elementally compute saturation vapor pressure over ice ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvsiq Elementally compute saturation vapor pressure over ice ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvsix Elementally compute saturation vapor pressure over ice ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! gpvs Compute saturation vapor pressure table ! ! fpvs Elementally compute saturation vapor pressure ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvsq Elementally compute saturation vapor pressure ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! fpvsx Elementally compute saturation vapor pressure ! function result Real(krealfp) saturation vapor pressure in Pascals ! t Real(krealfp) temperature in Kelvin ! ! gtdpl Compute dewpoint temperature over liquid table ! ! ftdpl Elementally compute dewpoint temperature over liquid ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdplq Elementally compute dewpoint temperature over liquid ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdplx Elementally compute dewpoint temperature over liquid ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdplxg Elementally compute dewpoint temperature over liquid ! function result Real(krealfp) dewpoint temperature in Kelvin ! t Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! gtdpi Compute dewpoint temperature table over ice ! ! ftdpi Elementally compute dewpoint temperature over ice ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpiq Elementally compute dewpoint temperature over ice ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpix Elementally compute dewpoint temperature over ice ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpixg Elementally compute dewpoint temperature over ice ! function result Real(krealfp) dewpoint temperature in Kelvin ! t Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! gtdp Compute dewpoint temperature table ! ! ftdp Elementally compute dewpoint temperature ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpq Elementally compute dewpoint temperature ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpx Elementally compute dewpoint temperature ! function result Real(krealfp) dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! ftdpxg Elementally compute dewpoint temperature ! function result Real(krealfp) dewpoint temperature in Kelvin ! t Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! gthe Compute equivalent potential temperature table ! ! fthe Elementally compute equivalent potential temperature ! function result Real(krealfp) equivalent potential temperature in Kelvin ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! ftheq Elementally compute equivalent potential temperature ! function result Real(krealfp) equivalent potential temperature in Kelvin ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! fthex Elementally compute equivalent potential temperature ! function result Real(krealfp) equivalent potential temperature in Kelvin ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! gtma Compute moist adiabat tables ! ! stma Elementally compute moist adiabat temperature and moisture ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! stmaq Elementally compute moist adiabat temperature and moisture ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! stmax Elementally compute moist adiabat temperature and moisture ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! stmaxg Elementally compute moist adiabat temperature and moisture ! tg Real(krealfp) guess parcel temperature in Kelvin ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! gpkap Compute pressure to the kappa table ! ! fpkap Elementally raise pressure to the kappa power. ! function result Real(krealfp) p over 1e5 Pa to the kappa power ! p Real(krealfp) pressure in Pascals ! ! fpkapq Elementally raise pressure to the kappa power. ! function result Real(krealfp) p over 1e5 Pa to the kappa power ! p Real(krealfp) pressure in Pascals ! ! fpkapo Elementally raise pressure to the kappa power. ! function result Real(krealfp) p over 1e5 Pa to the kappa power ! p Real(krealfp) surface pressure in Pascals ! ! fpkapx Elementally raise pressure to the kappa power. ! function result Real(krealfp) p over 1e5 Pa to the kappa power ! p Real(krealfp) pressure in Pascals ! ! grkap Compute pressure to the 1/kappa table ! ! frkap Elementally raise pressure to the 1/kappa power. ! function result Real(krealfp) pressure in Pascals ! pkap Real(krealfp) p over 1e5 Pa to the 1/kappa power ! ! frkapq Elementally raise pressure to the kappa power. ! function result Real(krealfp) pressure in Pascals ! pkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! frkapx Elementally raise pressure to the kappa power. ! function result Real(krealfp) pressure in Pascals ! pkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! gtlcl Compute LCL temperature table ! ! ftlcl Elementally compute LCL temperature. ! function result Real(krealfp) temperature at the LCL in Kelvin ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! ftlclq Elementally compute LCL temperature. ! function result Real(krealfp) temperature at the LCL in Kelvin ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! ftlclo Elementally compute LCL temperature. ! function result Real(krealfp) temperature at the LCL in Kelvin ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! ftlclx Elementally compute LCL temperature. ! function result Real(krealfp) temperature at the LCL in Kelvin ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! gfuncphys Compute all physics function tables ! ! Attributes: ! Language: Fortran 90 ! !$$$ use module_gfs_machine,only:kind_phys use module_gfs_physcons implicit none private ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! Public Variables ! integer,public,parameter:: krealfp=selected_real_kind(15,45) integer,public,parameter:: krealfp=kind_phys ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! Private Variables real(krealfp),parameter:: psatb=con_psat*1.e-5 integer,parameter:: nxpvsl=7501 real(krealfp) c1xpvsl,c2xpvsl,tbpvsl(nxpvsl) integer,parameter:: nxpvsi=7501 real(krealfp) c1xpvsi,c2xpvsi,tbpvsi(nxpvsi) integer,parameter:: nxpvs=7501 real(krealfp) c1xpvs,c2xpvs,tbpvs(nxpvs) integer,parameter:: nxtdpl=5001 real(krealfp) c1xtdpl,c2xtdpl,tbtdpl(nxtdpl) integer,parameter:: nxtdpi=5001 real(krealfp) c1xtdpi,c2xtdpi,tbtdpi(nxtdpi) integer,parameter:: nxtdp=5001 real(krealfp) c1xtdp,c2xtdp,tbtdp(nxtdp) integer,parameter:: nxthe=241,nythe=151 real(krealfp) c1xthe,c2xthe,c1ythe,c2ythe,tbthe(nxthe,nythe) integer,parameter:: nxma=151,nyma=121 real(krealfp) c1xma,c2xma,c1yma,c2yma,tbtma(nxma,nyma),tbqma(nxma,nyma) ! integer,parameter:: nxpkap=5501 integer,parameter:: nxpkap=11001 real(krealfp) c1xpkap,c2xpkap,tbpkap(nxpkap) integer,parameter:: nxrkap=5501 real(krealfp) c1xrkap,c2xrkap,tbrkap(nxrkap) integer,parameter:: nxtlcl=151,nytlcl=61 real(krealfp) c1xtlcl,c2xtlcl,c1ytlcl,c2ytlcl,tbtlcl(nxtlcl,nytlcl) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! Public Subprograms public gpvsl,fpvsl,fpvslq,fpvslx public gpvsi,fpvsi,fpvsiq,fpvsix public gpvs,fpvs,fpvsq,fpvsx public gtdpl,ftdpl,ftdplq,ftdplx,ftdplxg public gtdpi,ftdpi,ftdpiq,ftdpix,ftdpixg public gtdp,ftdp,ftdpq,ftdpx,ftdpxg public gthe,fthe,ftheq,fthex public gtma,stma,stmaq,stmax,stmaxg public gpkap,fpkap,fpkapq,fpkapo,fpkapx public grkap,frkap,frkapq,frkapx public gtlcl,ftlcl,ftlclq,ftlclo,ftlclx public gfuncphys contains !------------------------------------------------------------------------------- subroutine gpvsl !$$$ Subprogram Documentation Block ! ! Subprogram: gpvsl Compute saturation vapor pressure table over liquid ! Author: N Phillips W/NMC2X2 Date: 30 dec 82 ! ! Abstract: Computes saturation vapor pressure table as a function of ! temperature for the table lookup function fpvsl. ! Exact saturation vapor pressures are calculated in subprogram fpvslx. ! The current implementation computes a table with a length ! of 7501 for temperatures ranging from 180. to 330. Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: call gpvsl ! ! Subprograms called: ! (fpvslx) inlinable function to compute saturation vapor pressure ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,x,t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=180.0_krealfp xmax=330.0_krealfp xinc=(xmax-xmin)/(nxpvsl-1) ! c1xpvsl=1.-xmin/xinc c2xpvsl=1./xinc c1xpvsl=1.-xmin*c2xpvsl do jx=1,nxpvsl x=xmin+(jx-1)*xinc t=x tbpvsl(jx)=fpvslx(t) enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function fpvsl(t) function fpvsl(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsl Compute saturation vapor pressure over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A linear interpolation is done between values in a lookup table ! computed in gpvsl. See documentation for fpvslx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 6 decimal places. ! On the Cray, fpvsl is about 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: pvsl=fpvsl(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsl Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsl real(krealfp),intent(in):: t integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvsl+c2xpvsl*t,1._krealfp),real(nxpvsl,krealfp)) jx=min(xj,nxpvsl-1._krealfp) fpvsl=tbpvsl(jx)+(xj-jx)*(tbpvsl(jx+1)-tbpvsl(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvslq(t) function fpvslq(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvslq Compute saturation vapor pressure over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A quadratic interpolation is done between values in a lookup table ! computed in gpvsl. See documentation for fpvslx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 9 decimal places. ! On the Cray, fpvslq is about 3 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! ! Usage: pvsl=fpvslq(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvslq Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvslq real(krealfp),intent(in):: t integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvsl+c2xpvsl*t,1._krealfp),real(nxpvsl,krealfp)) jx=min(max(nint(xj),2),nxpvsl-1) dxj=xj-jx fj1=tbpvsl(jx-1) fj2=tbpvsl(jx) fj3=tbpvsl(jx+1) fpvslq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvslx(t) function fpvslx(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvslx Compute saturation vapor pressure over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute saturation vapor pressure from temperature. ! The water model assumes a perfect gas, constant specific heats ! for gas and liquid, and neglects the volume of the liquid. ! The model does account for the variation of the latent heat ! of condensation with temperature. The ice option is not included. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvsl=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: pvsl=fpvslx(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvslx Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvslx real(krealfp),intent(in):: t real(krealfp),parameter:: dldt=con_cvap-con_cliq real(krealfp),parameter:: heat=con_hvap real(krealfp),parameter:: xpona=-dldt/con_rv real(krealfp),parameter:: xponb=-dldt/con_rv+heat/(con_rv*con_ttp) real(krealfp) tr ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tr=con_ttp/t fpvslx=con_psat*(tr**xpona)*exp(xponb*(1.-tr)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gpvsi !$$$ Subprogram Documentation Block ! ! Subprogram: gpvsi Compute saturation vapor pressure table over ice ! Author: N Phillips W/NMC2X2 Date: 30 dec 82 ! ! Abstract: Computes saturation vapor pressure table as a function of ! temperature for the table lookup function fpvsi. ! Exact saturation vapor pressures are calculated in subprogram fpvsix. ! The current implementation computes a table with a length ! of 7501 for temperatures ranging from 180. to 330. Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: call gpvsi ! ! Subprograms called: ! (fpvsix) inlinable function to compute saturation vapor pressure ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,x,t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=180.0_krealfp xmax=330.0_krealfp xinc=(xmax-xmin)/(nxpvsi-1) ! c1xpvsi=1.-xmin/xinc c2xpvsi=1./xinc c1xpvsi=1.-xmin*c2xpvsi do jx=1,nxpvsi x=xmin+(jx-1)*xinc t=x tbpvsi(jx)=fpvsix(t) enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function fpvsi(t) function fpvsi(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsi Compute saturation vapor pressure over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A linear interpolation is done between values in a lookup table ! computed in gpvsi. See documentation for fpvsix for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 6 decimal places. ! On the Cray, fpvsi is about 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvsi=fpvsi(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsi Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsi real(krealfp),intent(in):: t integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvsi+c2xpvsi*t,1._krealfp),real(nxpvsi,krealfp)) jx=min(xj,nxpvsi-1._krealfp) fpvsi=tbpvsi(jx)+(xj-jx)*(tbpvsi(jx+1)-tbpvsi(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvsiq(t) function fpvsiq(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsiq Compute saturation vapor pressure over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A quadratic interpolation is done between values in a lookup table ! computed in gpvsi. See documentation for fpvsix for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 9 decimal places. ! On the Cray, fpvsiq is about 3 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvsi=fpvsiq(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsiq Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsiq real(krealfp),intent(in):: t integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvsi+c2xpvsi*t,1._krealfp),real(nxpvsi,krealfp)) jx=min(max(nint(xj),2),nxpvsi-1) dxj=xj-jx fj1=tbpvsi(jx-1) fj2=tbpvsi(jx) fj3=tbpvsi(jx+1) fpvsiq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvsix(t) function fpvsix(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsix Compute saturation vapor pressure over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute saturation vapor pressure from temperature. ! The water model assumes a perfect gas, constant specific heats ! for gas and ice, and neglects the volume of the ice. ! The model does account for the variation of the latent heat ! of condensation with temperature. The liquid option is not included. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvsi=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvsi=fpvsix(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsix Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsix real(krealfp),intent(in):: t real(krealfp),parameter:: dldt=con_cvap-con_csol real(krealfp),parameter:: heat=con_hvap+con_hfus real(krealfp),parameter:: xpona=-dldt/con_rv real(krealfp),parameter:: xponb=-dldt/con_rv+heat/(con_rv*con_ttp) real(krealfp) tr ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tr=con_ttp/t fpvsix=con_psat*(tr**xpona)*exp(xponb*(1.-tr)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gpvs !$$$ Subprogram Documentation Block ! ! Subprogram: gpvs Compute saturation vapor pressure table ! Author: N Phillips W/NMC2X2 Date: 30 dec 82 ! ! Abstract: Computes saturation vapor pressure table as a function of ! temperature for the table lookup function fpvs. ! Exact saturation vapor pressures are calculated in subprogram fpvsx. ! The current implementation computes a table with a length ! of 7501 for temperatures ranging from 180. to 330. Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: call gpvs ! ! Subprograms called: ! (fpvsx) inlinable function to compute saturation vapor pressure ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,x,t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=180.0_krealfp xmax=330.0_krealfp xinc=(xmax-xmin)/(nxpvs-1) ! c1xpvs=1.-xmin/xinc c2xpvs=1./xinc c1xpvs=1.-xmin*c2xpvs do jx=1,nxpvs x=xmin+(jx-1)*xinc t=x tbpvs(jx)=fpvsx(t) enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function fpvs(t) function fpvs(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvs Compute saturation vapor pressure ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A linear interpolation is done between values in a lookup table ! computed in gpvs. See documentation for fpvsx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 6 decimal places. ! On the Cray, fpvs is about 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvs=fpvs(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvs Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvs real(krealfp),intent(in):: t integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvs+c2xpvs*t,1._krealfp),real(nxpvs,krealfp)) jx=min(xj,nxpvs-1._krealfp) fpvs=tbpvs(jx)+(xj-jx)*(tbpvs(jx+1)-tbpvs(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvsq(t) function fpvsq(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsq Compute saturation vapor pressure ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute saturation vapor pressure from the temperature. ! A quadratic interpolation is done between values in a lookup table ! computed in gpvs. See documentation for fpvsx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is almost 9 decimal places. ! On the Cray, fpvsq is about 3 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvs=fpvsq(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsq Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsq real(krealfp),intent(in):: t integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpvs+c2xpvs*t,1._krealfp),real(nxpvs,krealfp)) jx=min(max(nint(xj),2),nxpvs-1) dxj=xj-jx fj1=tbpvs(jx-1) fj2=tbpvs(jx) fj3=tbpvs(jx+1) fpvsq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpvsx(t) function fpvsx(t) !$$$ Subprogram Documentation Block ! ! Subprogram: fpvsx Compute saturation vapor pressure ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute saturation vapor pressure from temperature. ! The saturation vapor pressure over either liquid and ice is computed ! over liquid for temperatures above the triple point, ! over ice for temperatures 20 degress below the triple point, ! and a linear combination of the two for temperatures in between. ! The water model assumes a perfect gas, constant specific heats ! for gas, liquid and ice, and neglects the volume of the condensate. ! The model does account for the variation of the latent heat ! of condensation and sublimation with temperature. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvsl=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! The reference for this computation is Emanuel(1994), pages 116-117. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: pvs=fpvsx(t) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! ! Output argument list: ! fpvsx Real(krealfp) saturation vapor pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpvsx real(krealfp),intent(in):: t real(krealfp),parameter:: tliq=con_ttp real(krealfp),parameter:: tice=con_ttp-20.0 real(krealfp),parameter:: dldtl=con_cvap-con_cliq real(krealfp),parameter:: heatl=con_hvap real(krealfp),parameter:: xponal=-dldtl/con_rv real(krealfp),parameter:: xponbl=-dldtl/con_rv+heatl/(con_rv*con_ttp) real(krealfp),parameter:: dldti=con_cvap-con_csol real(krealfp),parameter:: heati=con_hvap+con_hfus real(krealfp),parameter:: xponai=-dldti/con_rv real(krealfp),parameter:: xponbi=-dldti/con_rv+heati/(con_rv*con_ttp) real(krealfp) tr,w,pvl,pvi ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tr=con_ttp/t if(t.ge.tliq) then fpvsx=con_psat*(tr**xponal)*exp(xponbl*(1.-tr)) elseif(t.lt.tice) then fpvsx=con_psat*(tr**xponai)*exp(xponbi*(1.-tr)) else w=(t-tice)/(tliq-tice) pvl=con_psat*(tr**xponal)*exp(xponbl*(1.-tr)) pvi=con_psat*(tr**xponai)*exp(xponbi*(1.-tr)) fpvsx=w*pvl+(1.-w)*pvi endif ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gtdpl !$$$ Subprogram Documentation Block ! ! Subprogram: gtdpl Compute dewpoint temperature over liquid table ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature table as a function of ! vapor pressure for inlinable function ftdpl. ! Exact dewpoint temperatures are calculated in subprogram ftdplxg. ! The current implementation computes a table with a length ! of 5001 for vapor pressures ranging from 1 to 10001 Pascals ! giving a dewpoint temperature range of 208 to 319 Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: call gtdpl ! ! Subprograms called: ! (ftdplxg) inlinable function to compute dewpoint temperature over liquid ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,t,x,pv ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=1 xmax=10001 xinc=(xmax-xmin)/(nxtdpl-1) c1xtdpl=1.-xmin/xinc c2xtdpl=1./xinc t=208.0 do jx=1,nxtdpl x=xmin+(jx-1)*xinc pv=x t=ftdplxg(t,pv) tbtdpl(jx)=t enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function ftdpl(pv) function ftdpl(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpl Compute dewpoint temperature over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A linear interpolation is done between values in a lookup table ! computed in gtdpl. See documentation for ftdplxg for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.0005 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.02 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdpl is about 75 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: tdpl=ftdpl(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpl Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpl real(krealfp),intent(in):: pv integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdpl+c2xtdpl*pv,1._krealfp),real(nxtdpl,krealfp)) jx=min(xj,nxtdpl-1._krealfp) ftdpl=tbtdpl(jx)+(xj-jx)*(tbtdpl(jx+1)-tbtdpl(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdplq(pv) function ftdplq(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdplq Compute dewpoint temperature over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A quadratic interpolation is done between values in a lookup table ! computed in gtdpl. see documentation for ftdplxg for details. ! Input values outside table range are reset to table extrema. ! the interpolation accuracy is better than 0.00001 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.002 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdplq is about 60 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! ! Usage: tdpl=ftdplq(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdplq Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdplq real(krealfp),intent(in):: pv integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdpl+c2xtdpl*pv,1._krealfp),real(nxtdpl,krealfp)) jx=min(max(nint(xj),2),nxtdpl-1) dxj=xj-jx fj1=tbtdpl(jx-1) fj2=tbtdpl(jx) fj3=tbtdpl(jx+1) ftdplq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdplx(pv) function ftdplx(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdplx Compute dewpoint temperature over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: exactly compute dewpoint temperature from vapor pressure. ! An approximate dewpoint temperature for function ftdplxg ! is obtained using ftdpl so gtdpl must be already called. ! See documentation for ftdplxg for details. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: tdpl=ftdplx(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdplx Real(krealfp) dewpoint temperature in Kelvin ! ! Subprograms called: ! (ftdpl) inlinable function to compute dewpoint temperature over liquid ! (ftdplxg) inlinable function to compute dewpoint temperature over liquid ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdplx real(krealfp),intent(in):: pv real(krealfp) tg ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tg=ftdpl(pv) ftdplx=ftdplxg(tg,pv) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdplxg(tg,pv) function ftdplxg(tg,pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdplxg Compute dewpoint temperature over liquid ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute dewpoint temperature from vapor pressure. ! A guess dewpoint temperature must be provided. ! The water model assumes a perfect gas, constant specific heats ! for gas and liquid, and neglects the volume of the liquid. ! The model does account for the variation of the latent heat ! of condensation with temperature. The ice option is not included. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvs=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! The formula is inverted by iterating Newtonian approximations ! for each pvs until t is found to within 1.e-6 Kelvin. ! This function can be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: tdpl=ftdplxg(tg,pv) ! ! Input argument list: ! tg Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdplxg Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdplxg real(krealfp),intent(in):: tg,pv real(krealfp),parameter:: terrm=1.e-6 real(krealfp),parameter:: dldt=con_cvap-con_cliq real(krealfp),parameter:: heat=con_hvap real(krealfp),parameter:: xpona=-dldt/con_rv real(krealfp),parameter:: xponb=-dldt/con_rv+heat/(con_rv*con_ttp) real(krealfp) t,tr,pvt,el,dpvt,terr integer i ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - t=tg do i=1,100 tr=con_ttp/t pvt=con_psat*(tr**xpona)*exp(xponb*(1.-tr)) el=heat+dldt*(t-con_ttp) dpvt=el*pvt/(con_rv*t**2) terr=(pvt-pv)/dpvt t=t-terr if(abs(terr).le.terrm) exit enddo ftdplxg=t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gtdpi !$$$ Subprogram Documentation Block ! ! Subprogram: gtdpi Compute dewpoint temperature over ice table ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature table as a function of ! vapor pressure for inlinable function ftdpi. ! Exact dewpoint temperatures are calculated in subprogram ftdpixg. ! The current implementation computes a table with a length ! of 5001 for vapor pressures ranging from 0.1 to 1000.1 Pascals ! giving a dewpoint temperature range of 197 to 279 Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: call gtdpi ! ! Subprograms called: ! (ftdpixg) inlinable function to compute dewpoint temperature over ice ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,t,x,pv ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=0.1 xmax=1000.1 xinc=(xmax-xmin)/(nxtdpi-1) c1xtdpi=1.-xmin/xinc c2xtdpi=1./xinc t=197.0 do jx=1,nxtdpi x=xmin+(jx-1)*xinc pv=x t=ftdpixg(t,pv) tbtdpi(jx)=t enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function ftdpi(pv) function ftdpi(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpi Compute dewpoint temperature over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A linear interpolation is done between values in a lookup table ! computed in gtdpi. See documentation for ftdpixg for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.0005 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.02 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdpi is about 75 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdpi=ftdpi(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpi Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpi real(krealfp),intent(in):: pv integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdpi+c2xtdpi*pv,1._krealfp),real(nxtdpi,krealfp)) jx=min(xj,nxtdpi-1._krealfp) ftdpi=tbtdpi(jx)+(xj-jx)*(tbtdpi(jx+1)-tbtdpi(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpiq(pv) function ftdpiq(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpiq Compute dewpoint temperature over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A quadratic interpolation is done between values in a lookup table ! computed in gtdpi. see documentation for ftdpixg for details. ! Input values outside table range are reset to table extrema. ! the interpolation accuracy is better than 0.00001 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.002 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdpiq is about 60 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdpi=ftdpiq(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpiq Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpiq real(krealfp),intent(in):: pv integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdpi+c2xtdpi*pv,1._krealfp),real(nxtdpi,krealfp)) jx=min(max(nint(xj),2),nxtdpi-1) dxj=xj-jx fj1=tbtdpi(jx-1) fj2=tbtdpi(jx) fj3=tbtdpi(jx+1) ftdpiq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpix(pv) function ftdpix(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpix Compute dewpoint temperature over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: exactly compute dewpoint temperature from vapor pressure. ! An approximate dewpoint temperature for function ftdpixg ! is obtained using ftdpi so gtdpi must be already called. ! See documentation for ftdpixg for details. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdpi=ftdpix(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpix Real(krealfp) dewpoint temperature in Kelvin ! ! Subprograms called: ! (ftdpi) inlinable function to compute dewpoint temperature over ice ! (ftdpixg) inlinable function to compute dewpoint temperature over ice ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpix real(krealfp),intent(in):: pv real(krealfp) tg ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tg=ftdpi(pv) ftdpix=ftdpixg(tg,pv) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpixg(tg,pv) function ftdpixg(tg,pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpixg Compute dewpoint temperature over ice ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute dewpoint temperature from vapor pressure. ! A guess dewpoint temperature must be provided. ! The water model assumes a perfect gas, constant specific heats ! for gas and ice, and neglects the volume of the ice. ! The model does account for the variation of the latent heat ! of sublimation with temperature. The liquid option is not included. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvs=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! The formula is inverted by iterating Newtonian approximations ! for each pvs until t is found to within 1.e-6 Kelvin. ! This function can be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdpi=ftdpixg(tg,pv) ! ! Input argument list: ! tg Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpixg Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpixg real(krealfp),intent(in):: tg,pv real(krealfp),parameter:: terrm=1.e-6 real(krealfp),parameter:: dldt=con_cvap-con_csol real(krealfp),parameter:: heat=con_hvap+con_hfus real(krealfp),parameter:: xpona=-dldt/con_rv real(krealfp),parameter:: xponb=-dldt/con_rv+heat/(con_rv*con_ttp) real(krealfp) t,tr,pvt,el,dpvt,terr integer i ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - t=tg do i=1,100 tr=con_ttp/t pvt=con_psat*(tr**xpona)*exp(xponb*(1.-tr)) el=heat+dldt*(t-con_ttp) dpvt=el*pvt/(con_rv*t**2) terr=(pvt-pv)/dpvt t=t-terr if(abs(terr).le.terrm) exit enddo ftdpixg=t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gtdp !$$$ Subprogram Documentation Block ! ! Subprogram: gtdp Compute dewpoint temperature table ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature table as a function of ! vapor pressure for inlinable function ftdp. ! Exact dewpoint temperatures are calculated in subprogram ftdpxg. ! The current implementation computes a table with a length ! of 5001 for vapor pressures ranging from 0.5 to 1000.5 Pascals ! giving a dewpoint temperature range of 208 to 319 Kelvin. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: call gtdp ! ! Subprograms called: ! (ftdpxg) inlinable function to compute dewpoint temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,t,x,pv ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=0.5 xmax=10000.5 xinc=(xmax-xmin)/(nxtdp-1) c1xtdp=1.-xmin/xinc c2xtdp=1./xinc t=208.0 do jx=1,nxtdp x=xmin+(jx-1)*xinc pv=x t=ftdpxg(t,pv) tbtdp(jx)=t enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function ftdp(pv) function ftdp(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdp Compute dewpoint temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A linear interpolation is done between values in a lookup table ! computed in gtdp. See documentation for ftdpxg for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.0005 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.02 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdp is about 75 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdp=ftdp(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdp Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdp real(krealfp),intent(in):: pv integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdp+c2xtdp*pv,1._krealfp),real(nxtdp,krealfp)) jx=min(xj,nxtdp-1._krealfp) ftdp=tbtdp(jx)+(xj-jx)*(tbtdp(jx+1)-tbtdp(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpq(pv) function ftdpq(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpq Compute dewpoint temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute dewpoint temperature from vapor pressure. ! A quadratic interpolation is done between values in a lookup table ! computed in gtdp. see documentation for ftdpxg for details. ! Input values outside table range are reset to table extrema. ! the interpolation accuracy is better than 0.00001 Kelvin ! for dewpoint temperatures greater than 250 Kelvin, ! but decreases to 0.002 Kelvin for a dewpoint around 230 Kelvin. ! On the Cray, ftdpq is about 60 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdp=ftdpq(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpq Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpq real(krealfp),intent(in):: pv integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtdp+c2xtdp*pv,1._krealfp),real(nxtdp,krealfp)) jx=min(max(nint(xj),2),nxtdp-1) dxj=xj-jx fj1=tbtdp(jx-1) fj2=tbtdp(jx) fj3=tbtdp(jx+1) ftdpq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpx(pv) function ftdpx(pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpx Compute dewpoint temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: exactly compute dewpoint temperature from vapor pressure. ! An approximate dewpoint temperature for function ftdpxg ! is obtained using ftdp so gtdp must be already called. ! See documentation for ftdpxg for details. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdp=ftdpx(pv) ! ! Input argument list: ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpx Real(krealfp) dewpoint temperature in Kelvin ! ! Subprograms called: ! (ftdp) inlinable function to compute dewpoint temperature ! (ftdpxg) inlinable function to compute dewpoint temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpx real(krealfp),intent(in):: pv real(krealfp) tg ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tg=ftdp(pv) ftdpx=ftdpxg(tg,pv) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftdpxg(tg,pv) function ftdpxg(tg,pv) !$$$ Subprogram Documentation Block ! ! Subprogram: ftdpxg Compute dewpoint temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute dewpoint temperature from vapor pressure. ! A guess dewpoint temperature must be provided. ! The saturation vapor pressure over either liquid and ice is computed ! over liquid for temperatures above the triple point, ! over ice for temperatures 20 degress below the triple point, ! and a linear combination of the two for temperatures in between. ! The water model assumes a perfect gas, constant specific heats ! for gas, liquid and ice, and neglects the volume of the condensate. ! The model does account for the variation of the latent heat ! of condensation and sublimation with temperature. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formula ! pvsl=con_psat*(tr**xa)*exp(xb*(1.-tr)) ! where tr is ttp/t and other values are physical constants. ! The reference for this decision is Emanuel(1994), pages 116-117. ! The formula is inverted by iterating Newtonian approximations ! for each pvs until t is found to within 1.e-6 Kelvin. ! This function can be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! 2001-02-26 Iredell ice phase ! ! Usage: tdp=ftdpxg(tg,pv) ! ! Input argument list: ! tg Real(krealfp) guess dewpoint temperature in Kelvin ! pv Real(krealfp) vapor pressure in Pascals ! ! Output argument list: ! ftdpxg Real(krealfp) dewpoint temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftdpxg real(krealfp),intent(in):: tg,pv real(krealfp),parameter:: terrm=1.e-6 real(krealfp),parameter:: tliq=con_ttp real(krealfp),parameter:: tice=con_ttp-20.0 real(krealfp),parameter:: dldtl=con_cvap-con_cliq real(krealfp),parameter:: heatl=con_hvap real(krealfp),parameter:: xponal=-dldtl/con_rv real(krealfp),parameter:: xponbl=-dldtl/con_rv+heatl/(con_rv*con_ttp) real(krealfp),parameter:: dldti=con_cvap-con_csol real(krealfp),parameter:: heati=con_hvap+con_hfus real(krealfp),parameter:: xponai=-dldti/con_rv real(krealfp),parameter:: xponbi=-dldti/con_rv+heati/(con_rv*con_ttp) real(krealfp) t,tr,w,pvtl,pvti,pvt,ell,eli,el,dpvt,terr integer i ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - t=tg do i=1,100 tr=con_ttp/t if(t.ge.tliq) then pvt=con_psat*(tr**xponal)*exp(xponbl*(1.-tr)) el=heatl+dldtl*(t-con_ttp) dpvt=el*pvt/(con_rv*t**2) elseif(t.lt.tice) then pvt=con_psat*(tr**xponai)*exp(xponbi*(1.-tr)) el=heati+dldti*(t-con_ttp) dpvt=el*pvt/(con_rv*t**2) else w=(t-tice)/(tliq-tice) pvtl=con_psat*(tr**xponal)*exp(xponbl*(1.-tr)) pvti=con_psat*(tr**xponai)*exp(xponbi*(1.-tr)) pvt=w*pvtl+(1.-w)*pvti ell=heatl+dldtl*(t-con_ttp) eli=heati+dldti*(t-con_ttp) dpvt=(w*ell*pvtl+(1.-w)*eli*pvti)/(con_rv*t**2) endif terr=(pvt-pv)/dpvt t=t-terr if(abs(terr).le.terrm) exit enddo ftdpxg=t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gthe !$$$ Subprogram Documentation Block ! ! Subprogram: gthe Compute equivalent potential temperature table ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute equivalent potential temperature table ! as a function of LCL temperature and pressure over 1e5 Pa ! to the kappa power for function fthe. ! Equivalent potential temperatures are calculated in subprogram fthex ! the current implementation computes a table with a first dimension ! of 241 for temperatures ranging from 183.16 to 303.16 Kelvin ! and a second dimension of 151 for pressure over 1e5 Pa ! to the kappa power ranging from 0.04**rocp to 1.10**rocp. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: call gthe ! ! Subprograms called: ! (fthex) inlinable function to compute equiv. pot. temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx,jy real(krealfp) xmin,xmax,ymin,ymax,xinc,yinc,x,y,pk,t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=con_ttp-90._krealfp xmax=con_ttp+30._krealfp ymin=0.04_krealfp**con_rocp ymax=1.10_krealfp**con_rocp xinc=(xmax-xmin)/(nxthe-1) c1xthe=1.-xmin/xinc c2xthe=1./xinc yinc=(ymax-ymin)/(nythe-1) c1ythe=1.-ymin/yinc c2ythe=1./yinc do jy=1,nythe y=ymin+(jy-1)*yinc pk=y do jx=1,nxthe x=xmin+(jx-1)*xinc t=x tbthe(jx,jy)=fthex(t,pk) enddo enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function fthe(t,pk) function fthe(t,pk) !$$$ Subprogram Documentation Block ! ! Subprogram: fthe Compute equivalent potential temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute equivalent potential temperature at the LCL ! from temperature and pressure over 1e5 Pa to the kappa power. ! A bilinear interpolation is done between values in a lookup table ! computed in gthe. see documentation for fthex for details. ! Input values outside table range are reset to table extrema, ! except zero is returned for too cold or high LCLs. ! The interpolation accuracy is better than 0.01 Kelvin. ! On the Cray, fthe is almost 6 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: the=fthe(t,pk) ! ! Input argument list: ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! fthe Real(krealfp) equivalent potential temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fthe real(krealfp),intent(in):: t,pk integer jx,jy real(krealfp) xj,yj,ftx1,ftx2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(c1xthe+c2xthe*t,real(nxthe,krealfp)) yj=min(c1ythe+c2ythe*pk,real(nythe,krealfp)) if(xj.ge.1..and.yj.ge.1.) then jx=min(xj,nxthe-1._krealfp) jy=min(yj,nythe-1._krealfp) ftx1=tbthe(jx,jy)+(xj-jx)*(tbthe(jx+1,jy)-tbthe(jx,jy)) ftx2=tbthe(jx,jy+1)+(xj-jx)*(tbthe(jx+1,jy+1)-tbthe(jx,jy+1)) fthe=ftx1+(yj-jy)*(ftx2-ftx1) else fthe=0. endif ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftheq(t,pk) function ftheq(t,pk) !$$$ Subprogram Documentation Block ! ! Subprogram: ftheq Compute equivalent potential temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute equivalent potential temperature at the LCL ! from temperature and pressure over 1e5 Pa to the kappa power. ! A biquadratic interpolation is done between values in a lookup table ! computed in gthe. see documentation for fthex for details. ! Input values outside table range are reset to table extrema, ! except zero is returned for too cold or high LCLs. ! The interpolation accuracy is better than 0.0002 Kelvin. ! On the Cray, ftheq is almost 3 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! ! Usage: the=ftheq(t,pk) ! ! Input argument list: ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! ftheq Real(krealfp) equivalent potential temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftheq real(krealfp),intent(in):: t,pk integer jx,jy real(krealfp) xj,yj,dxj,dyj real(krealfp) ft11,ft12,ft13,ft21,ft22,ft23,ft31,ft32,ft33 real(krealfp) ftx1,ftx2,ftx3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(c1xthe+c2xthe*t,real(nxthe,krealfp)) yj=min(c1ythe+c2ythe*pk,real(nythe,krealfp)) if(xj.ge.1..and.yj.ge.1.) then jx=min(max(nint(xj),2),nxthe-1) jy=min(max(nint(yj),2),nythe-1) dxj=xj-jx dyj=yj-jy ft11=tbthe(jx-1,jy-1) ft12=tbthe(jx-1,jy) ft13=tbthe(jx-1,jy+1) ft21=tbthe(jx,jy-1) ft22=tbthe(jx,jy) ft23=tbthe(jx,jy+1) ft31=tbthe(jx+1,jy-1) ft32=tbthe(jx+1,jy) ft33=tbthe(jx+1,jy+1) ftx1=(((ft31+ft11)/2-ft21)*dxj+(ft31-ft11)/2)*dxj+ft21 ftx2=(((ft32+ft12)/2-ft22)*dxj+(ft32-ft12)/2)*dxj+ft22 ftx3=(((ft33+ft13)/2-ft23)*dxj+(ft33-ft13)/2)*dxj+ft23 ftheq=(((ftx3+ftx1)/2-ftx2)*dyj+(ftx3-ftx1)/2)*dyj+ftx2 else ftheq=0. endif ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fthex(t,pk) function fthex(t,pk) !$$$ Subprogram Documentation Block ! ! Subprogram: fthex Compute equivalent potential temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute equivalent potential temperature at the LCL ! from temperature and pressure over 1e5 Pa to the kappa power. ! Equivalent potential temperature is constant for a saturated parcel ! rising adiabatically up a moist adiabat when the heat and mass ! of the condensed water are neglected. Ice is also neglected. ! The formula for equivalent potential temperature (Holton) is ! the=t*(pd**(-rocp))*exp(el*eps*pv/(cp*t*pd)) ! where t is the temperature, pv is the saturated vapor pressure, ! pd is the dry pressure p-pv, el is the temperature dependent ! latent heat of condensation hvap+dldt*(t-ttp), and other values ! are physical constants defined in parameter statements in the code. ! Zero is returned if the input values make saturation impossible. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: the=fthex(t,pk) ! ! Input argument list: ! t Real(krealfp) LCL temperature in Kelvin ! pk Real(krealfp) LCL pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! fthex Real(krealfp) equivalent potential temperature in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fthex real(krealfp),intent(in):: t,pk real(krealfp) p,tr,pv,pd,el,expo,expmax ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - p=pk**con_cpor tr=con_ttp/t pv=psatb*(tr**con_xpona)*exp(con_xponb*(1.-tr)) pd=p-pv if(pd.gt.pv) then el=con_hvap+con_dldt*(t-con_ttp) expo=el*con_eps*pv/(con_cp*t*pd) fthex=t*pd**(-con_rocp)*exp(expo) else fthex=0. endif ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gtma !$$$ Subprogram Documentation Block ! ! Subprogram: gtma Compute moist adiabat tables ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute temperature and specific humidity tables ! as a function of equivalent potential temperature and ! pressure over 1e5 Pa to the kappa power for subprogram stma. ! Exact parcel temperatures are calculated in subprogram stmaxg. ! The current implementation computes a table with a first dimension ! of 151 for equivalent potential temperatures ranging from 200 to 500 ! Kelvin and a second dimension of 121 for pressure over 1e5 Pa ! to the kappa power ranging from 0.01**rocp to 1.10**rocp. ! ! Program History Log: ! 91-05-07 Iredell ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: call gtma ! ! Subprograms called: ! (stmaxg) inlinable subprogram to compute parcel temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx,jy real(krealfp) xmin,xmax,ymin,ymax,xinc,yinc,x,y,pk,the,t,q,tg ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=200._krealfp xmax=500._krealfp ymin=0.01_krealfp**con_rocp ymax=1.10_krealfp**con_rocp xinc=(xmax-xmin)/(nxma-1) c1xma=1.-xmin/xinc c2xma=1./xinc yinc=(ymax-ymin)/(nyma-1) c1yma=1.-ymin/yinc c2yma=1./yinc do jy=1,nyma y=ymin+(jy-1)*yinc pk=y tg=xmin*y do jx=1,nxma x=xmin+(jx-1)*xinc the=x call stmaxg(tg,the,pk,t,q) tbtma(jx,jy)=t tbqma(jx,jy)=q tg=t enddo enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental subroutine stma(the,pk,tma,qma) subroutine stma(the,pk,tma,qma) !$$$ Subprogram Documentation Block ! ! Subprogram: stma Compute moist adiabat temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute temperature and specific humidity of a parcel ! lifted up a moist adiabat from equivalent potential temperature ! at the LCL and pressure over 1e5 Pa to the kappa power. ! Bilinear interpolations are done between values in a lookup table ! computed in gtma. See documentation for stmaxg for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.01 Kelvin ! and 5.e-6 kg/kg for temperature and humidity, respectively. ! On the Cray, stma is about 35 times faster than exact calculation. ! This subprogram should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell expand table ! 1999-03-01 Iredell f90 module ! ! Usage: call stma(the,pk,tma,qma) ! ! Input argument list: ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp),intent(in):: the,pk real(krealfp),intent(out):: tma,qma integer jx,jy real(krealfp) xj,yj,ftx1,ftx2,qx1,qx2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xma+c2xma*the,1._krealfp),real(nxma,krealfp)) yj=min(max(c1yma+c2yma*pk,1._krealfp),real(nyma,krealfp)) jx=min(xj,nxma-1._krealfp) jy=min(yj,nyma-1._krealfp) ftx1=tbtma(jx,jy)+(xj-jx)*(tbtma(jx+1,jy)-tbtma(jx,jy)) ftx2=tbtma(jx,jy+1)+(xj-jx)*(tbtma(jx+1,jy+1)-tbtma(jx,jy+1)) tma=ftx1+(yj-jy)*(ftx2-ftx1) qx1=tbqma(jx,jy)+(xj-jx)*(tbqma(jx+1,jy)-tbqma(jx,jy)) qx2=tbqma(jx,jy+1)+(xj-jx)*(tbqma(jx+1,jy+1)-tbqma(jx,jy+1)) qma=qx1+(yj-jy)*(qx2-qx1) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental subroutine stmaq(the,pk,tma,qma) subroutine stmaq(the,pk,tma,qma) !$$$ Subprogram Documentation Block ! ! Subprogram: stmaq Compute moist adiabat temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute temperature and specific humidity of a parcel ! lifted up a moist adiabat from equivalent potential temperature ! at the LCL and pressure over 1e5 Pa to the kappa power. ! Biquadratic interpolations are done between values in a lookup table ! computed in gtma. See documentation for stmaxg for details. ! Input values outside table range are reset to table extrema. ! the interpolation accuracy is better than 0.0005 Kelvin ! and 1.e-7 kg/kg for temperature and humidity, respectively. ! On the Cray, stmaq is about 25 times faster than exact calculation. ! This subprogram should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell quadratic interpolation ! 1999-03-01 Iredell f90 module ! ! Usage: call stmaq(the,pk,tma,qma) ! ! Input argument list: ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! tmaq Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp),intent(in):: the,pk real(krealfp),intent(out):: tma,qma integer jx,jy real(krealfp) xj,yj,dxj,dyj real(krealfp) ft11,ft12,ft13,ft21,ft22,ft23,ft31,ft32,ft33 real(krealfp) ftx1,ftx2,ftx3 real(krealfp) q11,q12,q13,q21,q22,q23,q31,q32,q33,qx1,qx2,qx3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xma+c2xma*the,1._krealfp),real(nxma,krealfp)) yj=min(max(c1yma+c2yma*pk,1._krealfp),real(nyma,krealfp)) jx=min(max(nint(xj),2),nxma-1) jy=min(max(nint(yj),2),nyma-1) dxj=xj-jx dyj=yj-jy ft11=tbtma(jx-1,jy-1) ft12=tbtma(jx-1,jy) ft13=tbtma(jx-1,jy+1) ft21=tbtma(jx,jy-1) ft22=tbtma(jx,jy) ft23=tbtma(jx,jy+1) ft31=tbtma(jx+1,jy-1) ft32=tbtma(jx+1,jy) ft33=tbtma(jx+1,jy+1) ftx1=(((ft31+ft11)/2-ft21)*dxj+(ft31-ft11)/2)*dxj+ft21 ftx2=(((ft32+ft12)/2-ft22)*dxj+(ft32-ft12)/2)*dxj+ft22 ftx3=(((ft33+ft13)/2-ft23)*dxj+(ft33-ft13)/2)*dxj+ft23 tma=(((ftx3+ftx1)/2-ftx2)*dyj+(ftx3-ftx1)/2)*dyj+ftx2 q11=tbqma(jx-1,jy-1) q12=tbqma(jx-1,jy) q13=tbqma(jx-1,jy+1) q21=tbqma(jx,jy-1) q22=tbqma(jx,jy) q23=tbqma(jx,jy+1) q31=tbqma(jx+1,jy-1) q32=tbqma(jx+1,jy) q33=tbqma(jx+1,jy+1) qx1=(((q31+q11)/2-q21)*dxj+(q31-q11)/2)*dxj+q21 qx2=(((q32+q12)/2-q22)*dxj+(q32-q12)/2)*dxj+q22 qx3=(((q33+q13)/2-q23)*dxj+(q33-q13)/2)*dxj+q23 qma=(((qx3+qx1)/2-qx2)*dyj+(qx3-qx1)/2)*dyj+qx2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental subroutine stmax(the,pk,tma,qma) subroutine stmax(the,pk,tma,qma) !$$$ Subprogram Documentation Block ! ! Subprogram: stmax Compute moist adiabat temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Exactly compute temperature and humidity of a parcel ! lifted up a moist adiabat from equivalent potential temperature ! at the LCL and pressure over 1e5 Pa to the kappa power. ! An approximate parcel temperature for subprogram stmaxg ! is obtained using stma so gtma must be already called. ! See documentation for stmaxg for details. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: call stmax(the,pk,tma,qma) ! ! Input argument list: ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! Subprograms called: ! (stma) inlinable subprogram to compute parcel temperature ! (stmaxg) inlinable subprogram to compute parcel temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp),intent(in):: the,pk real(krealfp),intent(out):: tma,qma real(krealfp) tg,qg ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - call stma(the,pk,tg,qg) call stmaxg(tg,the,pk,tma,qma) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental subroutine stmaxg(tg,the,pk,tma,qma) subroutine stmaxg(tg,the,pk,tma,qma) !$$$ Subprogram Documentation Block ! ! Subprogram: stmaxg Compute moist adiabat temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: exactly compute temperature and humidity of a parcel ! lifted up a moist adiabat from equivalent potential temperature ! at the LCL and pressure over 1e5 Pa to the kappa power. ! A guess parcel temperature must be provided. ! Equivalent potential temperature is constant for a saturated parcel ! rising adiabatically up a moist adiabat when the heat and mass ! of the condensed water are neglected. Ice is also neglected. ! The formula for equivalent potential temperature (Holton) is ! the=t*(pd**(-rocp))*exp(el*eps*pv/(cp*t*pd)) ! where t is the temperature, pv is the saturated vapor pressure, ! pd is the dry pressure p-pv, el is the temperature dependent ! latent heat of condensation hvap+dldt*(t-ttp), and other values ! are physical constants defined in parameter statements in the code. ! The formula is inverted by iterating Newtonian approximations ! for each the and p until t is found to within 1.e-4 Kelvin. ! The specific humidity is then computed from pv and pd. ! This subprogram can be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell exact computation ! 1999-03-01 Iredell f90 module ! ! Usage: call stmaxg(tg,the,pk,tma,qma) ! ! Input argument list: ! tg Real(krealfp) guess parcel temperature in Kelvin ! the Real(krealfp) equivalent potential temperature in Kelvin ! pk Real(krealfp) pressure over 1e5 Pa to the kappa power ! ! Output argument list: ! tma Real(krealfp) parcel temperature in Kelvin ! qma Real(krealfp) parcel specific humidity in kg/kg ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp),intent(in):: tg,the,pk real(krealfp),intent(out):: tma,qma real(krealfp),parameter:: terrm=1.e-4 real(krealfp) t,p,tr,pv,pd,el,expo,thet,dthet,terr integer i ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - t=tg p=pk**con_cpor do i=1,100 tr=con_ttp/t pv=psatb*(tr**con_xpona)*exp(con_xponb*(1.-tr)) pd=p-pv el=con_hvap+con_dldt*(t-con_ttp) expo=el*con_eps*pv/(con_cp*t*pd) thet=t*pd**(-con_rocp)*exp(expo) dthet=thet/t*(1.+expo*(con_dldt*t/el+el*p/(con_rv*t*pd))) terr=(thet-the)/dthet t=t-terr if(abs(terr).le.terrm) exit enddo tma=t tr=con_ttp/t pv=psatb*(tr**con_xpona)*exp(con_xponb*(1.-tr)) pd=p-pv qma=con_eps*pv/(pd+con_eps*pv) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- subroutine gpkap !$$$ Subprogram documentation block ! ! Subprogram: gpkap Compute coefficients for p**kappa ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: Computes pressure to the kappa table as a function of pressure ! for the table lookup function fpkap. ! Exact pressure to the kappa values are calculated in subprogram fpkapx. ! The current implementation computes a table with a length ! of 5501 for pressures ranging up to 110000 Pascals. ! ! Program History Log: ! 94-12-30 Iredell ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: call gpkap ! ! Subprograms called: ! fpkapx function to compute exact pressure to the kappa ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,x,p ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=0._krealfp xmax=110000._krealfp xinc=(xmax-xmin)/(nxpkap-1) c1xpkap=1.-xmin/xinc c2xpkap=1./xinc do jx=1,nxpkap x=xmin+(jx-1)*xinc p=x tbpkap(jx)=fpkapx(p) enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function fpkap(p) function fpkap(p) !$$$ Subprogram Documentation Block ! ! Subprogram: fpkap raise pressure to the kappa power. ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Raise pressure over 1e5 Pa to the kappa power. ! A linear interpolation is done between values in a lookup table ! computed in gpkap. See documentation for fpkapx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy ranges from 9 decimal places ! at 100000 Pascals to 5 decimal places at 1000 Pascals. ! On the Cray, fpkap is over 5 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell standardized kappa, ! increased range and accuracy ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: pkap=fpkap(p) ! ! Input argument list: ! p Real(krealfp) pressure in Pascals ! ! Output argument list: ! fpkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpkap real(krealfp),intent(in):: p integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpkap+c2xpkap*p,1._krealfp),real(nxpkap,krealfp)) jx=min(xj,nxpkap-1._krealfp) fpkap=tbpkap(jx)+(xj-jx)*(tbpkap(jx+1)-tbpkap(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpkapq(p) function fpkapq(p) !$$$ Subprogram Documentation Block ! ! Subprogram: fpkapq raise pressure to the kappa power. ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Raise pressure over 1e5 Pa to the kappa power. ! A quadratic interpolation is done between values in a lookup table ! computed in gpkap. see documentation for fpkapx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy ranges from 12 decimal places ! at 100000 Pascals to 7 decimal places at 1000 Pascals. ! On the Cray, fpkap is over 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell standardized kappa, ! increased range and accuracy ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: pkap=fpkapq(p) ! ! Input argument list: ! p Real(krealfp) pressure in Pascals ! ! Output argument list: ! fpkapq Real(krealfp) p over 1e5 Pa to the kappa power ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpkapq real(krealfp),intent(in):: p integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xpkap+c2xpkap*p,1._krealfp),real(nxpkap,krealfp)) jx=min(max(nint(xj),2),nxpkap-1) dxj=xj-jx fj1=tbpkap(jx-1) fj2=tbpkap(jx) fj3=tbpkap(jx+1) fpkapq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- function fpkapo(p) !$$$ Subprogram documentation block ! ! Subprogram: fpkapo raise surface pressure to the kappa power. ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: Raise surface pressure over 1e5 Pa to the kappa power ! using a rational weighted chebyshev approximation. ! The numerator is of order 2 and the denominator is of order 4. ! The pressure range is 40000-110000 Pa and kappa is defined in fpkapx. ! The accuracy of this approximation is almost 8 decimal places. ! On the Cray, fpkap is over 10 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell standardized kappa, ! increased range and accuracy ! 1999-03-01 Iredell f90 module ! ! Usage: pkap=fpkapo(p) ! ! Input argument list: ! p Real(krealfp) surface pressure in Pascals ! p should be in the range 40000 to 110000 ! ! Output argument list: ! fpkapo Real(krealfp) p over 1e5 Pa to the kappa power ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpkapo real(krealfp),intent(in):: p integer,parameter:: nnpk=2,ndpk=4 real(krealfp):: cnpk(0:nnpk)=(/3.13198449e-1,5.78544829e-2,& 8.35491871e-4/) real(krealfp):: cdpk(0:ndpk)=(/1.,8.15968401e-2,5.72839518e-4,& -4.86959812e-7,5.24459889e-10/) integer n real(krealfp) pkpa,fnpk,fdpk ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - pkpa=p*1.e-3_krealfp fnpk=cnpk(nnpk) do n=nnpk-1,0,-1 fnpk=pkpa*fnpk+cnpk(n) enddo fdpk=cdpk(ndpk) do n=ndpk-1,0,-1 fdpk=pkpa*fdpk+cdpk(n) enddo fpkapo=fnpk/fdpk ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function fpkapx(p) function fpkapx(p) !$$$ Subprogram documentation block ! ! Subprogram: fpkapx raise pressure to the kappa power. ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: raise pressure over 1e5 Pa to the kappa power. ! Kappa is equal to rd/cp where rd and cp are physical constants. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 94-12-30 Iredell made into inlinable function ! 1999-03-01 Iredell f90 module ! ! Usage: pkap=fpkapx(p) ! ! Input argument list: ! p Real(krealfp) pressure in Pascals ! ! Output argument list: ! fpkapx Real(krealfp) p over 1e5 Pa to the kappa power ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) fpkapx real(krealfp),intent(in):: p ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - fpkapx=(p/1.e5_krealfp)**con_rocp ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine grkap !$$$ Subprogram documentation block ! ! Subprogram: grkap Compute coefficients for p**(1/kappa) ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: Computes pressure to the 1/kappa table as a function of pressure ! for the table lookup function frkap. ! Exact pressure to the 1/kappa values are calculated in subprogram frkapx. ! The current implementation computes a table with a length ! of 5501 for pressures ranging up to 110000 Pascals. ! ! Program History Log: ! 94-12-30 Iredell ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: call grkap ! ! Subprograms called: ! frkapx function to compute exact pressure to the 1/kappa ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx real(krealfp) xmin,xmax,xinc,x,p ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=0._krealfp xmax=fpkapx(110000._krealfp) xinc=(xmax-xmin)/(nxrkap-1) c1xrkap=1.-xmin/xinc c2xrkap=1./xinc do jx=1,nxrkap x=xmin+(jx-1)*xinc p=x tbrkap(jx)=frkapx(p) enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function frkap(pkap) function frkap(pkap) !$$$ Subprogram Documentation Block ! ! Subprogram: frkap raise pressure to the 1/kappa power. ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Raise pressure over 1e5 Pa to the 1/kappa power. ! A linear interpolation is done between values in a lookup table ! computed in grkap. See documentation for frkapx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 7 decimal places. ! On the IBM, fpkap is about 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell standardized kappa, ! increased range and accuracy ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: p=frkap(pkap) ! ! Input argument list: ! pkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! Output argument list: ! frkap Real(krealfp) pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) frkap real(krealfp),intent(in):: pkap integer jx real(krealfp) xj ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xrkap+c2xrkap*pkap,1._krealfp),real(nxrkap,krealfp)) jx=min(xj,nxrkap-1._krealfp) frkap=tbrkap(jx)+(xj-jx)*(tbrkap(jx+1)-tbrkap(jx)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function frkapq(pkap) function frkapq(pkap) !$$$ Subprogram Documentation Block ! ! Subprogram: frkapq raise pressure to the 1/kappa power. ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Raise pressure over 1e5 Pa to the 1/kappa power. ! A quadratic interpolation is done between values in a lookup table ! computed in grkap. see documentation for frkapx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 11 decimal places. ! On the IBM, fpkap is almost 4 times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 94-12-30 Iredell standardized kappa, ! increased range and accuracy ! 1999-03-01 Iredell f90 module ! 1999-03-24 Iredell table lookup ! ! Usage: p=frkapq(pkap) ! ! Input argument list: ! pkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! Output argument list: ! frkapq Real(krealfp) pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) frkapq real(krealfp),intent(in):: pkap integer jx real(krealfp) xj,dxj,fj1,fj2,fj3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xrkap+c2xrkap*pkap,1._krealfp),real(nxrkap,krealfp)) jx=min(max(nint(xj),2),nxrkap-1) dxj=xj-jx fj1=tbrkap(jx-1) fj2=tbrkap(jx) fj3=tbrkap(jx+1) frkapq=(((fj3+fj1)/2-fj2)*dxj+(fj3-fj1)/2)*dxj+fj2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function frkapx(pkap) function frkapx(pkap) !$$$ Subprogram documentation block ! ! Subprogram: frkapx raise pressure to the 1/kappa power. ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: raise pressure over 1e5 Pa to the 1/kappa power. ! Kappa is equal to rd/cp where rd and cp are physical constants. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 94-12-30 Iredell made into inlinable function ! 1999-03-01 Iredell f90 module ! ! Usage: p=frkapx(pkap) ! ! Input argument list: ! pkap Real(krealfp) p over 1e5 Pa to the kappa power ! ! Output argument list: ! frkapx Real(krealfp) pressure in Pascals ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) frkapx real(krealfp),intent(in):: pkap ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - frkapx=pkap**(1/con_rocp)*1.e5_krealfp ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gtlcl !$$$ Subprogram Documentation Block ! ! Subprogram: gtlcl Compute equivalent potential temperature table ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute lifting condensation level temperature table ! as a function of temperature and dewpoint depression for function ftlcl. ! Lifting condensation level temperature is calculated in subprogram ftlclx ! The current implementation computes a table with a first dimension ! of 151 for temperatures ranging from 180.0 to 330.0 Kelvin ! and a second dimension of 61 for dewpoint depression ranging from ! 0 to 60 Kelvin. ! ! Program History Log: ! 1999-03-01 Iredell f90 module ! ! Usage: call gtlcl ! ! Subprograms called: ! (ftlclx) inlinable function to compute LCL temperature ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none integer jx,jy real(krealfp) xmin,xmax,ymin,ymax,xinc,yinc,x,y,tdpd,t ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xmin=180._krealfp xmax=330._krealfp ymin=0._krealfp ymax=60._krealfp xinc=(xmax-xmin)/(nxtlcl-1) c1xtlcl=1.-xmin/xinc c2xtlcl=1./xinc yinc=(ymax-ymin)/(nytlcl-1) c1ytlcl=1.-ymin/yinc c2ytlcl=1./yinc do jy=1,nytlcl y=ymin+(jy-1)*yinc tdpd=y do jx=1,nxtlcl x=xmin+(jx-1)*xinc t=x tbtlcl(jx,jy)=ftlclx(t,tdpd) enddo enddo ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- ! elemental function ftlcl(t,tdpd) function ftlcl(t,tdpd) !$$$ Subprogram Documentation Block ! ! Subprogram: ftlcl Compute LCL temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute temperature at the lifting condensation level ! from temperature and dewpoint depression. ! A bilinear interpolation is done between values in a lookup table ! computed in gtlcl. See documentation for ftlclx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.0005 Kelvin. ! On the Cray, ftlcl is ? times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 1999-03-01 Iredell f90 module ! ! Usage: tlcl=ftlcl(t,tdpd) ! ! Input argument list: ! t Real(krealfp) LCL temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! Output argument list: ! ftlcl Real(krealfp) temperature at the LCL in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftlcl real(krealfp),intent(in):: t,tdpd integer jx,jy real(krealfp) xj,yj,ftx1,ftx2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtlcl+c2xtlcl*t,1._krealfp),real(nxtlcl,krealfp)) yj=min(max(c1ytlcl+c2ytlcl*tdpd,1._krealfp),real(nytlcl,krealfp)) jx=min(xj,nxtlcl-1._krealfp) jy=min(yj,nytlcl-1._krealfp) ftx1=tbtlcl(jx,jy)+(xj-jx)*(tbtlcl(jx+1,jy)-tbtlcl(jx,jy)) ftx2=tbtlcl(jx,jy+1)+(xj-jx)*(tbtlcl(jx+1,jy+1)-tbtlcl(jx,jy+1)) ftlcl=ftx1+(yj-jy)*(ftx2-ftx1) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftlclq(t,tdpd) function ftlclq(t,tdpd) !$$$ Subprogram Documentation Block ! ! Subprogram: ftlclq Compute LCL temperature ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute temperature at the lifting condensation level ! from temperature and dewpoint depression. ! A biquadratic interpolation is done between values in a lookup table ! computed in gtlcl. see documentation for ftlclx for details. ! Input values outside table range are reset to table extrema. ! The interpolation accuracy is better than 0.000003 Kelvin. ! On the Cray, ftlclq is ? times faster than exact calculation. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 1999-03-01 Iredell f90 module ! ! Usage: tlcl=ftlclq(t,tdpd) ! ! Input argument list: ! t Real(krealfp) LCL temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! Output argument list: ! ftlcl Real(krealfp) temperature at the LCL in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftlclq real(krealfp),intent(in):: t,tdpd integer jx,jy real(krealfp) xj,yj,dxj,dyj real(krealfp) ft11,ft12,ft13,ft21,ft22,ft23,ft31,ft32,ft33 real(krealfp) ftx1,ftx2,ftx3 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xj=min(max(c1xtlcl+c2xtlcl*t,1._krealfp),real(nxtlcl,krealfp)) yj=min(max(c1ytlcl+c2ytlcl*tdpd,1._krealfp),real(nytlcl,krealfp)) jx=min(max(nint(xj),2),nxtlcl-1) jy=min(max(nint(yj),2),nytlcl-1) dxj=xj-jx dyj=yj-jy ft11=tbtlcl(jx-1,jy-1) ft12=tbtlcl(jx-1,jy) ft13=tbtlcl(jx-1,jy+1) ft21=tbtlcl(jx,jy-1) ft22=tbtlcl(jx,jy) ft23=tbtlcl(jx,jy+1) ft31=tbtlcl(jx+1,jy-1) ft32=tbtlcl(jx+1,jy) ft33=tbtlcl(jx+1,jy+1) ftx1=(((ft31+ft11)/2-ft21)*dxj+(ft31-ft11)/2)*dxj+ft21 ftx2=(((ft32+ft12)/2-ft22)*dxj+(ft32-ft12)/2)*dxj+ft22 ftx3=(((ft33+ft13)/2-ft23)*dxj+(ft33-ft13)/2)*dxj+ft23 ftlclq=(((ftx3+ftx1)/2-ftx2)*dyj+(ftx3-ftx1)/2)*dyj+ftx2 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- function ftlclo(t,tdpd) !$$$ Subprogram documentation block ! ! Subprogram: ftlclo Compute LCL temperature. ! Author: Phillips org: w/NMC2X2 Date: 29 dec 82 ! ! Abstract: Compute temperature at the lifting condensation level ! from temperature and dewpoint depression. the formula used is ! a polynomial taken from Phillips mstadb routine which empirically ! approximates the original exact implicit relationship. ! (This kind of approximation is customary (inman, 1969), but ! the original source for this particular one is not yet known. -MI) ! Its accuracy is about 0.03 Kelvin for a dewpoint depression of 30. ! This function should be expanded inline in the calling routine. ! ! Program History Log: ! 91-05-07 Iredell made into inlinable function ! 1999-03-01 Iredell f90 module ! ! Usage: tlcl=ftlclo(t,tdpd) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! Output argument list: ! ftlclo Real(krealfp) temperature at the LCL in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftlclo real(krealfp),intent(in):: t,tdpd real(krealfp),parameter:: clcl1= 0.954442e+0,clcl2= 0.967772e-3,& clcl3=-0.710321e-3,clcl4=-0.270742e-5 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ftlclo=t-tdpd*(clcl1+clcl2*t+tdpd*(clcl3+clcl4*t)) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- ! elemental function ftlclx(t,tdpd) function ftlclx(t,tdpd) !$$$ Subprogram documentation block ! ! Subprogram: ftlclx Compute LCL temperature. ! Author: Iredell org: w/NMC2X2 Date: 25 March 1999 ! ! Abstract: Compute temperature at the lifting condensation level ! from temperature and dewpoint depression. A parcel lifted ! adiabatically becomes saturated at the lifting condensation level. ! The water model assumes a perfect gas, constant specific heats ! for gas and liquid, and neglects the volume of the liquid. ! The model does account for the variation of the latent heat ! of condensation with temperature. The ice option is not included. ! The Clausius-Clapeyron equation is integrated from the triple point ! to get the formulas ! pvlcl=con_psat*(trlcl**xa)*exp(xb*(1.-trlcl)) ! pvdew=con_psat*(trdew**xa)*exp(xb*(1.-trdew)) ! where pvlcl is the saturated parcel vapor pressure at the LCL, ! pvdew is the unsaturated parcel vapor pressure initially, ! trlcl is ttp/tlcl and trdew is ttp/tdew. The adiabatic lifting ! of the parcel is represented by the following formula ! pvdew=pvlcl*(t/tlcl)**(1/kappa) ! This formula is inverted by iterating Newtonian approximations ! until tlcl is found to within 1.e-6 Kelvin. Note that the minimum ! returned temperature is 180 Kelvin. ! ! Program History Log: ! 1999-03-25 Iredell ! ! Usage: tlcl=ftlclx(t,tdpd) ! ! Input argument list: ! t Real(krealfp) temperature in Kelvin ! tdpd Real(krealfp) dewpoint depression in Kelvin ! ! Output argument list: ! ftlclx Real(krealfp) temperature at the LCL in Kelvin ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none real(krealfp) ftlclx real(krealfp),intent(in):: t,tdpd real(krealfp),parameter:: terrm=1.e-4,tlmin=180.,tlminx=tlmin-5. real(krealfp) tr,pvdew,tlcl,ta,pvlcl,el,dpvlcl,terr,terrp integer i ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - tr=con_ttp/(t-tdpd) pvdew=con_psat*(tr**con_xpona)*exp(con_xponb*(1.-tr)) tlcl=t-tdpd do i=1,100 tr=con_ttp/tlcl ta=t/tlcl pvlcl=con_psat*(tr**con_xpona)*exp(con_xponb*(1.-tr))*ta**(1/con_rocp) el=con_hvap+con_dldt*(tlcl-con_ttp) dpvlcl=(el/(con_rv*t**2)+1/(con_rocp*tlcl))*pvlcl terr=(pvlcl-pvdew)/dpvlcl tlcl=tlcl-terr if(abs(terr).le.terrm.or.tlcl.lt.tlminx) exit enddo ftlclx=max(tlcl,tlmin) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end function !------------------------------------------------------------------------------- subroutine gfuncphys !$$$ Subprogram Documentation Block ! ! Subprogram: gfuncphys Compute all physics function tables ! Author: N Phillips w/NMC2X2 Date: 30 dec 82 ! ! Abstract: Compute all physics function tables. Lookup tables are ! set up for computing saturation vapor pressure, dewpoint temperature, ! equivalent potential temperature, moist adiabatic temperature and humidity, ! pressure to the kappa, and lifting condensation level temperature. ! ! Program History Log: ! 1999-03-01 Iredell f90 module ! ! Usage: call gfuncphys ! ! Subprograms called: ! gpvsl compute saturation vapor pressure over liquid table ! gpvsi compute saturation vapor pressure over ice table ! gpvs compute saturation vapor pressure table ! gtdpl compute dewpoint temperature over liquid table ! gtdpi compute dewpoint temperature over ice table ! gtdp compute dewpoint temperature table ! gthe compute equivalent potential temperature table ! gtma compute moist adiabat tables ! gpkap compute pressure to the kappa table ! grkap compute pressure to the 1/kappa table ! gtlcl compute LCL temperature table ! ! Attributes: ! Language: Fortran 90. ! !$$$ implicit none ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - call gpvsl call gpvsi call gpvs call gtdpl call gtdpi call gtdp call gthe call gtma call gpkap call grkap call gtlcl ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - end subroutine !------------------------------------------------------------------------------- end module module_gfs_funcphys