The longest satellite soil moisture record available — merged active+passive retrievals back to 1978, free, no login.
SMAP
ActiveNASA's L-band radiometer soil moisture mission — 9km/36km near-surface moisture, daily, since 2015.
by NASA / NSIDC
- Pricing
- Gov-Public
- License
- US Government (public domain)
- Commercial use
- Permitted
- Ecosystem
- Google Earth Engine, Python
- Platform
- Windows, macOS, Linux
About SMAP
SMAP (Soil Moisture Active Passive) measures near-surface (top ~5cm) soil moisture globally using an L-band radiometer, distributed through NSIDC at 9km (enhanced) and 36km resolution with roughly 2-3 day repeat coverage since 2015. An L4 product adds a model-based root-zone soil moisture estimate for users needing depth beyond the radiometer's shallow sensing.
It is the reference satellite soil-moisture mission for drought monitoring, irrigation scheduling and antecedent-moisture inputs to event-based rainfall-runoff models, with a data record now long enough for trend analysis.
Where it fits in the workflow
TerrainCatchmentRainfallRunoffRoutingHydraulicsMappingReporting
Appears in collections
- Satellite Data for Hydrology & Water Engineering
The satellite and reanalysis datasets H&H engineers actually reach for — DEM to GRACE.
Alternatives to SMAP
Ranked by the topics, categories and workflow stages they share with SMAP.
Google Earth Engine
Freemium
Planetary-scale geospatial analysis in the cloud — the data catalogue and compute behind modern water remote sensing.
ASCAT Soil Moisture (H SAF)
Gov-Public
Near-real-time scatterometer soil moisture from EUMETSAT — hours of latency, useful for operational monitoring.
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 Snow Cover
Gov-Public
500m daily/8-day global snow-cover extent from MODIS — the standard optical snow product for basin-scale tracking.