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Full catalog/SPL2SMAP_S
SPL2SMAP_S·v003·dataset

How wet the soil is, sharpened by radar (SMAP+Sentinel-1, 3 km)

SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture V003
land NASA NSIDC_CPRD Level 2 active HDF5
In plain English

What it measures. How wet the top layer of soil is, mapped at a sharp 3 km resolution. It combines a soil-moisture sensor with radar to add fine spatial detail.

How it's made. Derived by merging SMAP's L-band microwave readings (how the soil 'glows' in microwaves, which depends on its wetness) with Sentinel-1 radar echoes, resampled onto a 3 km grid.

How & where you'd use it. Useful for agriculture, drought tracking, and flood prediction where finer detail than coarse soil-moisture maps is needed. Note the 1 km version is not validated and should be used cautiously.

What's measured

SPECTRAL/ENGINEERING › MICROWAVE › BRIGHTNESS TEMPERATURESPECTRAL/ENGINEERING › RADAR › SIGMA NAUGHTLAND SURFACE › SOILS › SOIL MOISTURE/WATER CONTENT › SURFACE SOIL MOISTURE

Coverage & cadence

  • Time span2015-03-31 → ongoing
  • Measured bySMAP (SMAP L-BAND RADIOMETER) · Sentinel-1A (C-SAR) · Sentinel-1B (C-SAR)
  • Processing levelLevel 2
  • Spatial extent-180, -60, 180, 60
  • FormatsHDF5
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

This Level-2 (L2) soil moisture product provides estimates of land surface conditions retrieved by both the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes and the Sentinel-1A and -1B radar. SMAP L-band brightness temperatures and Copernicus Sentinel-1 C-band backscatter coefficients are used to derive soil moisture data, which are then resampled to an Earth-fixed, cylindrical 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0). While the 3 km data product has undergone validation, the 1 km product has not and should be used with caution.

Get the data

spl2smap_s_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SPL2SMAP_S",
    version="003",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from NSIDC_CPRD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.