The longest satellite soil moisture record available — merged active+passive retrievals back to 1978, free, no login.
10 tools · Topic
Drought Analysis & Index Tools
SPI, SPEI, PDSI and their many cousins — drought indices quantify deficit for triggers, monitoring and planning. Listed here are packages that compute the standard indices, plus the satellite soil-moisture, vegetation and water-storage data drought studies draw on.
GRACE / GRACE-FO Mascons
Gov-Public
Monthly total water storage change from satellite gravity — the only direct signal of large-scale groundwater depletion.
Google Earth Engine
Freemium
Planetary-scale geospatial analysis in the cloud — the data catalogue and compute behind modern water remote sensing.
MODIS NDVI/EVI (MOD13Q1)
Gov-Public
250m, 16-day global vegetation index composites — the standard input to crop-coefficient ET and drought indices.
SMAP
Gov-Public
NASA's L-band radiometer soil moisture mission — 9km/36km near-surface moisture, daily, since 2015.
SPEI (R package)
Open Source
The reference R implementation of SPEI and SPI from the index's own authors.
USGS Hydrologic Toolbox
Gov-Public
USGS's merged surface-water and groundwater statistics program — baseflow separation, flow duration, low flows.
VIC
Open Source
The Variable Infiltration Capacity model — macroscale land-surface hydrology for big basins and climate studies.
climate_indices
Open Source
Reference Python implementations of SPI, SPEI and Palmer indices for drought monitoring.
xclim
Open Source
Climate indices and bias adjustment on xarray — the operational-grade library for climate-data engineering.