2022-07-27 15:43:19 +08:00

37 lines
1.2 KiB
Python

from org.meteoinfo.math.meteo import MeteoMath
from mipylib.numeric.core import DimArray
from .. import constants
from ..calc.thermo import temperature_from_potential_temperature
from destag import destagger
__all__ = ['get_slp']
def get_slp(wrfin, timeidx=0, units='hPa'):
"""
Return the sea level pressure in the specified units.
This function extracts the necessary variables from the NetCDF file
object in order to perform the calculation.
:param wrfin: (*DimDataFile*) Data file.
:param timeidx: (*int*) Time index.
:param units: (*string*) The desired units.
:returns: (*array*) Sea level pressure.
"""
t = wrfin['T'][timeidx,:,:,:]
p = wrfin['P'][timeidx,:,:,:]
pb = wrfin['PB'][timeidx,:,:,:]
qvapor = wrfin['QVAPOR'][timeidx,:,:,:]
ph = wrfin['PH'][timeidx,:,:,:]
phb = wrfin['PHB'][timeidx,:,:,:]
full_t = t + constants.T_BASE
full_p = p + pb
qvapor[qvapor < 0] = 0.
full_ph = (ph + phb) / constants.g
destag_ph = destagger(full_ph, -3)
tk = temperature_from_potential_temperature(full_p * 0.01, full_t)
slp = MeteoMath.calSeaPrs(destag_ph._array, tk._array, full_p._array, qvapor._array)
return DimArray(slp, dims=t.dims[1:])