geocat.comp.interpolation._temp_extrapolate#
- geocat.comp.interpolation._temp_extrapolate(data, lev_dim, lev, p_sfc, ps, phi_sfc)#
This helper function extrapolates temperature below ground using the ECMWF formulation described in Vertical Interpolation and Truncation of Model-Coordinate Data by Trenberth, Berry, & Buja [NCAR/TN-396, 1993]. Specifically equation 16 is used:
\[T = T_* \left( 1 + \alpha ln \frac{p}{p_s} + \frac{1}{2}\left( \alpha ln \frac{p}{p_s} \right)^2 + \frac{1}{6} \left( \alpha ln \frac{p}{p_s} \right)^3 \right)\]- Parameters
data (
xarray.DataArray
) – The temperature at the lowest level of the model.lev_dim (
str
) – The name of the vertical dimension.lev (
int
) – The pressure levels of interest. Must be in the same units asps
andp_sfc
p_sfc (
xarray.DataArray
) – The pressure at the lowest level of the model. Must be in the same units aslev
andps
ps (
xarray.DataArray
) – An array of surface pressures. Must be in the same units aslev
andp_sfc
phi_sfc (
xarray.DataArray
) – The geopotential at the lowest level of the model.
- Returns
result (
xarray.DataArray
) – The extrapolated temepratures at the provided pressure levels.