getvar returns ['GSW' is not a valid variable name]; extract_vars returns [got multiple values for argument 'timeidx']

[phalucy]

Dear all,

I'm now working on an issue that needs the net heat flux at surface. To calculate it, I need the variables including GSW, GLW, TSK, EMISS, GRDFLX, HFX, and LH. The others are easily obtainded by wrf.getvar function, but I failed in getting the variable GSW, and the error message is here:

gsw = wrf.getvar(wrflist, "GSW", timeidx=t,  @method="cat")
  File "/Users/abc/anaconda3/envs/pygmt/lib/python3.10/site-packages/wrf/ro
utines.py", line 352, in getvar
    raise ValueError("'{}' is not a valid variable name".format(varname))
ValueError: 'GSW' is not a valid variable name

I checked the wrfout file and confirmed there is a variable named 'GSW' (I could also plot it):

float GSW(Time, south_north, west_east) ;
        GSW:FieldType = 104 ;
        GSW:MemoryOrder = "XY " ;
        GSW:description = "NET SHORT WAVE FLUX AT GROUND SURFACE" ;
        GSW:units = "W m-2" ;
        GSW:stagger = "" ;
        GSW:coordinates = "XLONG XLAT XTIME" ;

After that, I tried to use wrf.extract_vars to get the variables that originally embedded in the wrfout file, but I also got error

gsw = wrf.extract_vars(wrflist, "GSW", timeidx=t, method="cat")
TypeError: extract_vars() got multiple values for argument 'timeidx'

The argument 'timeidx=t' works fine in other variables such as GLW, etc.

Is this a bug or I need special way to extract GSW? For now, I could only get 'SWDOWN' and 'ALBEDO' seperately and calculate GSW by myself.

[kafitzgerald]

Hi @phalucy, thanks for the question.

You'll need to use wrf.extract_vars since "GSW" is a variable in the file rather than one of the supported diagnostics.

I'm not quite sure offhand what's going on with the TypeError from wrf.extract_vars. Do you have a short example to reproduce this?

[phalucy]

Hi @kafitzgerald, thank you for your reply, but I'm sorry I don't have an smaller-enough example that could be uploaded. Now I'm OK by calculating GSW based on SWDOWN and ALBEDO.

Meanwhile, I wish to know why some variables (such as GLW, ALBEDO, SWDOWN, etc.) were obtained successfully by the 'getvar' function, which are also not supported diagnostics.

[kafitzgerald]

My apologies, I misspoke about wrf.getvar vs wrf.extract_vars. You should be able to just use wrf.getvar. However, I'm still not quite sure why you're seeing the ValueError with wrf.getvar and haven't been able to replicate it.

I think you may be able to get wrf.extract_vars to work by specifying the variable name as a keyword argument vs. a positional argument (see below) or swapping the order so the arguments align with what's expected. Interestingly the varnames and timeidx are specified in a different order from getvar.

gsw = wrf.extract_vars(wrflist, varnames=["GSW"], timeidx=t, method="cat")