WRF学习之 ch5 WRF模式（四）运行WRF（f-h）： 移动嵌套网格，分析Nudging，观测Nudging【待译】
Chapter 5: WRF Model
from https://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/v4.1/users_guide_chap5.html
Table of Contents
• Introduction
• Installing WRF
• Running WRF
a. Idealized Case
b. Real Data Case
c. Restart Run
d. Two-Way Nested Runs
e. One-Way Nested Run Using ndown
f. Moving Nested Run
g. Analysis Nudging Runs
h. Observation Nudging
i. Global Run
j. DFI Run
k. SST Update
l. Using bucket_mm and bucket_J options
m. Adaptive Time Stepping
n. Stochastic Parameterization Schemes
o. Run-Time IO
p. Output Diagnostics
q. WRF-Hydro
r. Using IO Quilting
s. Using Physics Suites
t. Hybrid Vertical Coordinate.
• Examples of namelists for various applications
• Check Output
• Trouble Shooting
• Physics and Dynamics Options
• Summary of PBL Physics Options
• Summary of Microphysics Options
• Summary of Cumulus Parameterization Options
• Summary of Radiation Options
• Description of Namelist Variables
• WRF Output Fields
• Special WRF Output Variables
f. 移动嵌套的运行
在WRF中可以使用两种类型的移动网格。第一种类型，用户可以在namelist中指定嵌套的移动。第二种类型，嵌套是自动移动的，基于自动化的涡旋跟踪算法。这个方法是用于对一个足够完美的热带气旋进行追踪。
为了实现特定的移动嵌套运行，选取正确的编译选项（选项‘preset moves’）。为了使用这个选项，代码必须以分布式内存并行选项（dmpar）编译，从而利用多个处理器。需要注意这个编译的代码不支持静态的嵌套运行。为了运行模式，仅仅只需要粗网格的输入场。在此选项下，嵌套初始化由粗网格——不需要嵌套输入场——提供。除了namelist选项被用在嵌套运行外，在namelist中的&domain部分需要加入如下选项:
num_moves: 在模式运行中可以移动的总数。在任何domain的移动都将计入此总数。当前的最大值设置为50，但可以通过将文件frame/module_driver_constants.F中的变量MAX_MOVES进行修改。
move_id: 一组嵌套网格的IDs, 每一个移动一个嵌套，指定要移动那个domain。
move_interval: the number of minutes from the beginning of the run until a move is supposed to occur. The nest will move on the next time step after the specified instant of model time has passed.
move_cd_x,move_cd_y: distance in the number of grid points and direction of the nest move (positive numbers indicate moving toward east and north, while negative numbers indicate moving toward west and south).
Parameter max_moves is set to be 50, but can be modified in the source code file frame/module_driver_constants.F, if needed.
To make the automatic moving nested runs, select the ‘vortex-following’ option when configuring. To use this option, the code must be configured for the distributed-memory parallelization option (dmpar) to make use of multiple processors. Again note that this compile would only support the auto-moving nest, and will not support the specified moving nested run or static nested run at the same time. Again, no nest input is needed. If one wants to use values other than the default ones, add and edit the following namelist variables in the &domains section:
vortex_interval: how often the vortex position is calculated in minutes (default is 15 minutes).
max_vortex_speed: used with vortex_interval to compute the search radius for the new vortex center position (default is 40 m/sec).
corral_dist: the distance in the number of coarse grid cells that the moving nest is allowed to get near the mother domain boundary (default is 8). This parameter can be used to center the telescoped nests so that all nests are moved together with the storm.
track_level: the pressure level (in Pa) where the vortex is tracked.
time_to_move: the time (in minutes) to move a nest. This option may help with the case when the storm is still too weak to be tracked by the algorithm.
When the automatic moving nest is employed, the model dumps the vortex center location, with minimum mean sea-level pressure and maximum 10-m winds in a standard-out file (e.g. rsl.out.0000). Typing ‘grep ATCF rsl.out.0000’ will produce a list of storm information at a 15-minute interval:
ATCF 2007-08-20_12:00:00 20.37 -81.80 929.7 133.9
ATCF 2007-08-20_12:15:00 20.29 -81.76 929.3 133.2
In both types of moving-nest runs, the initial location of the nest is specified through i_parent_start and j_parent_start in the namelist.input file.
Since V3.6, a capability has been added to incorporate high-resolution terrain and landuse input in a moving nest run (Chen, Shuyi S., Wei Zhao, Mark A. Donelan, James F. Price, Edward J. Walsh, 2007: The CBLAST-Hurricane Program and the Next-Generation Fully Coupled Atmosphere–Wave–Ocean Models for Hurricane Research and Prediction. Bull. Amer. Meteor. Soc., 88, 311–317.doi: http://dx.doi.org/10.1175/BAMS-88-3-311). To activate this option,
- At compile time, one needs to set the environment variable, TERRAIN_AND_LANDUSE to 1. In cshell,
setenv TERRAIN_AND_LANDUSE 1
followed by configuring and compiling the code.
Beginning with V3.9 of WPS, the default landuse data set is changed to MODIS; however this high-resolution dataset is from USGS, and therefore in order to use this capability, your landuse data should be prepared using USGS. - At run time, add these namelists in &time_control:
input_from_hires = .true., .true.,
rsmas_data_path = “terrain_and_landuse_data_directory”
The automatic moving nest works best for a well-developed vortex.
g. Analysis Nudging Runs (Upper-Air and/or Surface)
Prepare input data to WRF as usual using WPS. If nudging is desired in the nest domains, make sure all time periods for all domains are processed in WPS. For surface-analysis nudging (new in Version 3.1), OBSGRID needs to be run after METGRID, and it will output a wrfsfdda_d01 file that the WRF model reads for this option.
Set the following options before running real.exe, in addition to others described earlier (see the namelists in examples.namelist in the test/em_real/ directory, for guidance):
grid_fdda = 1
grid_sfdda = 1
Run real.exe as before, and this will create, in addition to wrfinput_d0* and wrfbdy_d01 files, a file named ‘wrffdda_d0*’. Other grid-nudging namelists are ignored at this stage, but it is good practice to fill them all in before one runs real. In particular, set
gfdda_inname = “wrffdda_d
gfdda_interval = time interval of input data in minutes
gfdda_end_h = end time of grid-nudging in hours
sgfdda_inname = “wrfsfdda_d
sgfdda_interval = time interval of input data in minutes
sgfdda_end_h = end time of surface grid-nudging in hours
See http://www2.mmm.ucar.edu/wrf/users/wrfv3.1/How_to_run_grid_fdda.html and README.grid_fdda in WRF/test/em_real/ for more information.
A different surface data nudging option is added in V3.8, and activated by setting
grid_sfdda = 2
This option nudges surface air temperature and water vapor mixing ratio similar to that with option 1, but uses the tendencies generated from the direct nudging approach to constrain surface sensible and latent heat fluxes, thus ensuring thermodynamic consistency between the atmosphere and land surface. This works with YSU PBL and Noah LSM. (Alapaty et al. JAMC, 2008)
Spectral Nudging is another upper-air nudging option. This selectively nudges the coarser scales only, but is otherwise set up the same way as grid-nudging. This option also nudges geopotential height. The wave numbers defined here are the number of waves contained in the domain, and the number is the maximum one that is nudged.
grid_fdda = 2
xwavenum = 3
ywavenum = 3
h. Observation Nudging Run
In addition to the usual input data preparation using WPS, station observation files are required. See the Observation Nudging User's Guide and http://www2.mmm.ucar.edu/wrf/users/wrfv3.1/How_to_run_obs_fdda.html for details. The observation file names expected by WRF are OBS_DOMAIN101 for domain 1, and OBS_DOMAIN201 for domain 2, etc.
Observation nudging is activated in the model by the following namelists in &fdda:
obs_nudge_opt = 1
fdda_start = 0 (obs nudging start time in minutes)
fdda_end = 360 (obs nudging end time in minutes)
and in &time_control
auxinput11_interval_s = 180, 180, 180, (set the interval to be small enough so
that all observations will be checked)
Look for an example to set other obs nudging namelist variables in the file examples.namelists in test/em_real/ directory. See The Observation Nudging User's Guide, http://www2.mmm.ucar.edu/wrf/users/wrfv3.1/How_to_run_obs_fdda.html, and README.obs_fdda in WRF/test/em_real/ for more information.
posted @ 2021-01-12 16:34
