Calculating sea level pressure from XWRF processed WRF output file

[steiner273]

I am just getting started with XWRF and so far have familiarized myself with getting my WRF output working with xarray and metpy calc functions. But I am in need of a sea level pressure calculation routine for my data and I can't seem to find anything outside of the wrf-python routines. What I tried to do was use wrf.slp but I keep getting this error:

wrf.extension.DiagnosticError: Error in finding 100 hPa up. i= 1 j= 1 sfc_p= 10.148610839843750

Here is the python code where I make the calculation:

ds = xr.open_dataset(files[24], engine='netcdf4').xwrf.postprocess()
destaggered = ds.xwrf.destagger().metpy.quantify().drop_vars("CLAT")
air_pressure = destaggered.air_pressure.pint.to('hPa').metpy.dequantify()

geohght = destaggered.geopotential_height.metpy.assign_coordinates({'latitude': 'XLAT'})
ptk = destaggered.air_potential_temperature.metpy.dequantify()

##calculate temperature
temp = tk(air_pressure, ptk)

#calculate sea level pressure

qv = destaggered.QVAPOR.metpy.dequantify()
mslp_calc = slp(geohght.metpy.dequantify(), temp.metpy.dequantify(), air_pressure, qv)

Is there something incompatible with using the wrf-python routines or do I need to find another way of calculating the sea level pressure? I noticed that metpy does not have a mean sea level pressure calculation yet...

Thanks!

[lpilz]

Hey!

I'm not super sure why the wrf-python routine is failing, I don't really know the algorithm myself - maybe have a look at the source code here: https://github.com/NCAR/wrf-python/blob/302bd5f3dcc6df2d476869d3d25433879883f695/fortran/wrf_user.f90#L355

Also, I might be wrong but doesn't the metpy.calc.altimeter_to_sea_level_pressure function do just the sea level pressure calculation you need?