CROPWAT
Free
FAO's classic tool for crop water requirements and irrigation scheduling from climate and crop data.
9 tools · Topic
Evapotranspiration Calculation Tools
Whether you need FAO-56 Penman-Monteith reference ET for an irrigation schedule or actual ET from satellite data for a water balance, the list covers both: equation implementations such as pyet and CROPWAT, satellite ET products such as MODIS ET and SSEBop, and the temperature and vegetation data those products are built from.
MIKE SHE
Commercial
DHI's integrated hydrological model — coupled overland, unsaturated, groundwater and channel flow.
MODIS ET (MOD16)
Gov-Public
Global actual ET from MODIS, 500m, 8-day/monthly/annual — a Penman-Monteith water-balance term, ready-made.
MODIS LST
Gov-Public
1km daily/8-day land surface temperature from MODIS — the standard thermal input for energy-balance ET and snowmelt.
MODIS NDVI/EVI (MOD13Q1)
Gov-Public
250m, 16-day global vegetation index composites — the standard input to crop-coefficient ET and drought indices.
SPEI (R package)
Open Source
The reference R implementation of SPEI and SPI from the index's own authors.
SSEBop
Gov-Public
USGS operational ET at Landsat resolution — 30m actual evapotranspiration for water-rights and irrigation accounting.
Visual MODFLOW Flex
Commercial
3D groundwater flow and transport modeling environment for MODFLOW, SEAWAT, and PEST calibration workflows.
pyet
Open Source
Reference and potential evapotranspiration in Python — 20+ published methods, FAO-56 included, on pandas/xarray.