earth2studio.models.dx.DerivedVPD#
- class earth2studio.models.dx.DerivedVPD(levels=[100])[source]#
Calculates the Vapor Pressure Deficit (VPD) in hPa from relative humidity and temperature fields. The calculation is based on the formula:
VPD = es * ((100 - rh) / 100)
The variable es is the saturation vapor pressure calculated using the formula:
es = 6.11 * exp((L / Rv) * ((1 / 273) - (1 / T)))
where L is the latent heat of vaporization (2.26e6 J/kg), Rv is the gas constant for water vapor (461 J/kg/K).
Note
For additional information on the VPD calculation in millibars, please refer to:
Dennis Hartman “Global Physical Climatology” (p 350)
https://www.sciencedirect.com/book/9780123285317/global-physical-climatology
- Parameters:
levels (list[int | str], optional) – Pressure / height levels to compute VPD for. The resulting expected input fields are temperature and relative humidity pairs for each level. E.g. for level 100 the input fields should be [t100, r100], by default [100]