1. 在提取变量前查看.nc 文件的变量信息
Note: for WRF variable names and their definitions, you can easily check them by using "ncl_filedump":
ncl_filedump wrfout_d01_2000-01-24_12:00:00.nc(注意你在用Tab,补全命令时是不会加surfix.nc的,所以你自己加上后缀才可以,否则报错)
2.如何提取诊断变量slp(因为slp不是输出变量)
两个函数 wrf_slp() wrf_usr_getvar()
Example 1
T = nc_file->T(time,:,:,:) th = T + 300. P = nc_file->P(time,:,:,:) PB = nc_file->PB(time,:,:,:) p = ( P + PB ) tk = wrf_tk( p , th ) QVAPOR = nc_file->QVAPOR(time,:,:,:) PH = nc_file->PH(time,:,:,:) PHB = nc_file->PHB(time,:,:,:) var = ( PH + PHB ) / 9.81 dim = dimsizes(var) z = 0.5 * ( var(0:dim(0)-2,:,:) + var(1:dim(0)-1,:,:) ) slp = wrf_slp( z, tk, p, QVAPOR )
Example 2
The function wrf_user_getvar, (available in the $NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl script)
can also be used to calculate many diagnostics in one step.
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" a = addfile("wrfout_d01_2000-01-24_12:00:00.nc","r") time = 1 slp = wrf_user_getvar(a,"slp",time) ; calculate SLP
You can see some other example scripts and their resultant images at:
http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/