source: lmdz_wrf/trunk/WRFV3/test/em_real/README.grid_fdda @ 206

Last change on this file since 206 was 1, checked in by lfita, 11 years ago
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WRF: version v3.3
LMDZ: version v1818

More details in:

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1Running grid nudging
2--------------------
3Grid nudging is available in Version 2.2.
4This nudges the WRF run towards a gridded analysis linearly interpolated in time between
5specified analyses. It only requires multiple time periods of analyses for each domain
6to be nudged, and these are input to real in the same format as the initial conditions.
7To run an fdda job
8
9- run real.exe with grid_fdda = 1
10  This will generate an extra input file with the time-varying analyses called wrffdda_d0<n>
11- note that each domain can have grid_fdda = 1 or 0 when running nesting
12- run wrf.exe with the same grid_fdda setting to use the wrffdda files generated
13  Also select wrf run-time options from the list described below to determine which fields to nudge,
14    how strongly to nudge, whether to nudge in the boundary layer, or whether to truncate
15    nudging below a certain grid level
16- There is a ramping capability for dynamic initialization that turns nudging off over a
17    specified period
18
19 &fdda
20 grid_fdda (max_dom)                 = 1        ; grid-nudging fdda on (=0 off) for each domain
21 gfdda_inname                        = "wrffdda_d<domain>" ; defined name in real
22 gfdda_interval_m (max_dom)          = 360      ; time interval (min) between analysis times
23 gfdda_end_h (max_dom)               = 6        ; time (h) to stop nudging after start of forecast
24 io_form_gfdda                       = 2        ; analysis data io format (2 = netCDF)
25 fgdt (max_dom)                      = 0        ; calculation frequency (minutes) for grid-nudging (0=every step)
26 if_no_pbl_nudging_uv (max_dom)      = 0        ; 1= no nudging of u and v in the pbl, 0=nudging in the pbl
27 if_no_pbl_nudging_t (max_dom)       = 0        ; 1= no nudging of temp in the pbl, 0=nudging in the pbl
28 if_no_pbl_nudging_q (max_dom)       = 0        ; 1= no nudging of qvapor in the pbl, 0=nudging in the pbl
29 if_zfac_uv (max_dom)                = 0        ; 0= nudge u and v all layers, 1= limit nudging to levels above k_zfac_uv
30  k_zfac_uv (max_dom)                = 10       ; 10=model level below which nudging is switched off for u and v
31 if_zfac_t (max_dom)                 = 0        ; 0= nudge temp all layers, 1= limit nudging to levels above k_zfac_t
32  k_zfac_t (max_dom)                 = 10       ; 10=model level below which nudging is switched off for temp
33 if_zfac_q (max_dom)                 = 0        ; 0= nudge qvapor all layers, 1= limit nudging to levels above k_zfac_q
34  k_zfac_q (max_dom)                 = 10       ; 10=model level below which nudging is switched off for qvapor
35 guv (max_dom)                       = 0.0003   ; nudging coefficient for u and v (sec-1)
36 gt (max_dom)                        = 0.0003   ; nudging coefficient for temp (sec-1)
37 gq (max_dom)                        = 0.0003   ; nudging coefficient for qvapor (sec-1)
38 if_ramping                          = 0        ; 0= nudging ends as a step function, 1= ramping nudging down at end of period
39 dtramp_min                          = 60.0     ; time (min) for ramping function, 60.0=ramping starts at last analysis time,
40                                                                                  -60.0=ramping ends at last analysis time
41
42 grid_sfdda (max_dom)                = 0        ; surface fdda switch (1, on; 0, off)
43 sgfdda_inname                       = "wrfsfdda_d<domain>" ; defined name for sfc nudgingn input file (from program obsgrid)
44 sgfdda_end_h (max_dom)              = 6        ; time (in hours) to stop sfc nudging after start of forecast
45 sgfdda_interval_m (max_dom)         = 180      ; time interval (in min) between sfc analysis times (must use minutes)
46 io_form_sgfdda                      = 2        ; sfc analysis data io format (2 = netCDF)
47 guv_sfc (max_dom)                   = 0.0003   ; nudging coefficient for sfc u and v (sec-1)
48 gt_sfc (max_dom)                    = 0.0003   ; nudging coefficient for sfc temp (sec-1)
49 gq_sfc (max_dom)                    = 0.0003   ; nudging coefficient for sfc qvapor (sec-1)
50 rinblw                              = 250.0    ; radius
51
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