Table 1 PET input variables as estimated from ERA5 variables.
From: Global climate-driven trade-offs between the water retention and cooling benefits of urban greening
Input variable | FAO56 definition | Estimation |
|---|---|---|
Rn | Net radiation at the crop surface [MJ m-2 day-1] | Derived from ERA5 surface net solar/thermal radiation |
G | Soil heat flux density [MJ m-2 day-1] | Following Eq 42 in ref. 36 Gday ≈ zero |
T | Mean daily air temperature at 2 m height [°C] | ERA5 2 m temperature |
u2 | Wind speed at 2 m height [m s-1] | Derived from ERA5 10 m u and v components and downscaled using Eq 47 in ref. 36 |
es | Saturation vapor pressure [kPa] | Estimated from ERA5 2 m temperature using Eq. 11 in ref. 36 |
ea | Actual vapor pressure [kPa] | Estimated from ERA5 2 m dewpoint temperature using Eq 14 in ref. 36 |
γ | Psychrometric constant [kPa °C-1] | Estimated using Eqs. 7 and 8 from ref. 36 using ERA5 geopotential to derive elevation above sea level |
Δ | Slope vapor pressure curve [kPa °C-1] | Estimated from ERA5 2 m temperature using Eq 13 from ref. 36 |
