SUBROUTINE SURDI

!**** *SURDI*   - INITIALIZE COMMON YOERDI CONTROLLING RADINT

!     PURPOSE.
!     --------
!           INITIALIZE YOERDI, THE COMMON THAT CONTROLS THE
!           RADIATION INTERFACE

!**   INTERFACE.
!     ----------
!        CALL *SURDI* FROM *SURAD*
!              -----        -----

!        EXPLICIT ARGUMENTS :
!        --------------------
!        NONE

!        IMPLICIT ARGUMENTS :
!        --------------------
!        COMMON YOERDI

!     METHOD.
!     -------
!        SEE DOCUMENTATION

!     EXTERNALS.
!     ----------
!        NONE

!     REFERENCE.
!     ----------
!        ECMWF RESEARCH DEPARTMENT DOCUMENTATION OF THE IFS MODEL

!     AUTHOR.
!     -------
!      Original  JEAN-JACQUES MORCRETTE  *ECMWF*
!      ORIGINAL : 88-12-15

!     MODIFICATIONS.
!     --------------
!      M.Hamrud      01-Oct-2003 CY28 Cleaning
!      Modified   P. Viterbo   24-05-2004  surf library
!      JJMorcrette   2004-10-07 Gas concentrations
!     ------------------------------------------------------------------

USE PARKIND1  ,ONLY : JPRB
USE YOMHOOK   ,ONLY : LHOOK,   DR_HOOK

USE YOERDI   , ONLY : RRAE     ,&
 & RCARDI   ,RCH4     ,RN2O     ,RNO2     ,RO3      ,&
 & RCFC11   ,RCFC12   ,RCFC22   ,RCCL4    ,&
 & REPCLC   ,REPH2O   ,RSUNDUR  ,&
 & RCCO2    ,RCCH4    ,RCN2O    ,RCNO2    ,RCCFC11  ,&
 & RCCFC12  ,RCCFC22  ,RCCCL4
USE YOMDYNCORE, ONLY : LAQUA

IMPLICIT NONE

REAL(KIND=JPRB) :: ZAIRMWG, ZC11MWG, ZC12MWG, ZCH4MWG, ZCO2MWG,&
 & ZN2OMWG, ZNO2MWG, ZO3MWG, ZC22MWG, ZCL4MWG
REAL(KIND=JPRB) :: ZHOOK_HANDLE

!      ----------------------------------------------------------------

!*       1.    SET DEFAULT VALUES.
!              -------------------

IF (LHOOK) CALL DR_HOOK('SURDI',0,ZHOOK_HANDLE)
RRAE = 0.1277E-02_JPRB

!* Threshold for computing sunshine duration (W/m2)
RSUNDUR=120._JPRB

!*  For sea ice, monthly values are based on Ebert and Curry, 1993, Table 2.
!   We take dry snow albedo as the representative value for non-summer
!   months, and bare sea-ice as the representative value for summer
!   months. The values for Antarctic are shifted six-months.
! All computations brought back to *SUSWN*

!*  Concentration of the various trace gases (IPCC/SACC values for 1990)
!        CO2         CH4        N2O        CFC11       CFC12
!      353ppmv     1.72ppmv   310ppbv     280pptv     484pptv

ZAIRMWG = 28.970_JPRB
ZCO2MWG = 44.011_JPRB
ZCH4MWG = 16.043_JPRB
ZN2OMWG = 44.013_JPRB
ZNO2MWG = 46.006_JPRB
ZO3MWG  = 47.9982_JPRB
ZC11MWG = 137.3686_JPRB
ZC12MWG = 120.9140_JPRB
ZC22MWG =  86.4690_JPRB
ZCL4MWG = 153.8230_JPRB

!RCARDI  = 353.E-06_JPRB*ZCO2MWG/ZAIRMWG
!RCH4    = 1.72E-06_JPRB*ZCH4MWG/ZAIRMWG
!RN2O    = 310.E-09_JPRB*ZN2OMWG/ZAIRMWG
!RNO2    = 500.E-13_JPRB*ZNO2MWG/ZAIRMWG
!RO3     =   1.E-06_JPRB*ZO3MWG /ZAIRMWG
!RCFC11  = 280.E-12_JPRB*ZC11MWG/ZAIRMWG
!RCFC12  = 484.E-12_JPRB*ZC12MWG/ZAIRMWG
!RCFC22  =   1.E-12_JPRB*ZC22MWG/ZAIRMWG
!RCCL4   =   1.E-12_JPRB*ZCL4MWG/ZAIRMWG

IF( LAQUA ) THEN
  RCARDI  = 348.E-06_JPRB*ZCO2MWG/ZAIRMWG
  RCH4    = 1.65E-06_JPRB*ZCH4MWG/ZAIRMWG
  RN2O    = 306.E-09_JPRB*ZN2OMWG/ZAIRMWG
ELSE
  RCARDI  = RCCO2   * ZCO2MWG/ZAIRMWG
  RCH4    = RCCH4   * ZCH4MWG/ZAIRMWG
  RN2O    = RCN2O   * ZN2OMWG/ZAIRMWG
ENDIF

RNO2    = RCNO2   * ZNO2MWG/ZAIRMWG 
RO3     = 1.E-06_JPRB*ZO3MWG /ZAIRMWG
RCFC11  = RCCFC11 * ZC11MWG/ZAIRMWG
RCFC12  = RCCFC12 * ZC12MWG/ZAIRMWG
RCFC22  = RCCFC22 * ZC22MWG/ZAIRMWG
RCCL4   = RCCCL4  * ZCL4MWG/ZAIRMWG

REPCLC=1.E-12_JPRB
REPH2O=1.E-12_JPRB

!     -----------------------------------------------------------------

IF (LHOOK) CALL DR_HOOK('SURDI',1,ZHOOK_HANDLE)
END SUBROUTINE SURDI