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Full catalog/NSIDC-0800
NSIDC-0800·v1·dataset

How wet the soil is (SMAP and SMOS, 9 km)

SMAP/SMOS L3 Radiometer 9 km EASE-Grid Soil Moisture V001
land NASA NSIDC_CPRD Level 3 HDF5
In plain English

What it measures. Daily estimates of how much moisture is in the top layer of soil, mapped worldwide on a 9-kilometer grid. It also includes the natural microwave glow that surfaces give off, which the satellites use to work out the moisture, plus a measure of how dense the overlying vegetation is.

How it's made. It blends measurements from two L-band satellites, SMAP and SMOS, combining their readings so the same spot gets revisited roughly once a day instead of every 2-3 days, then gridding the results.

How & where you'd use it. Helps track fast-changing water conditions like how quickly soil dries out after a storm, groundwater draining and refilling, and how saturated the ground is before rain, which matters for predicting runoff and flooding.

What's measured

SPECTRAL/ENGINEERING › MICROWAVE › BRIGHTNESS TEMPERATURELAND SURFACE › SOILS › SOIL MOISTURE/WATER CONTENT › SURFACE SOIL MOISTUREBIOSPHERE › VEGETATION › VEGETATION OPTICAL DEPTH

Coverage & cadence

  • Time span2015-05-01 → 2021-12-31
  • Measured bySMAP (SMAP L-BAND RADIOMETER) · SMOS (SMOS L-BAND RADIOMETER)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF5
  • StatusCOMPLETE

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

The Soil Moisture Active Passive (SMAP, launched in 2015) and the Soil Moisture and Ocean Salinity (SMOS, launched in 2009) missions are each L-band satellites that provide brightness temperature and soil moisture estimates and vegetation optical depth approximately every 2-3 days with a spatial resolution of ~40 km. By integrating brightness temperature observations from both satellites, these data products reduce the revisit time to about one day, improving the ability to monitor fast-response processes such as groundwater drainage and recharge, early dry-down after storms, and pre-storm soil moisture conditions for runoff determination. The Integrated SMAP and SMOS Soil Moisture Data is available in two products. The SMOS-Based SMAP L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture (NSIDC-0799) product is generated by processing half-orbit granules (either 6 AM ascending or 6 PM descending) from the pre-processed SMOS product. The L2 product consists solely of SMOS-based data, incorporating information after SMOS brightness temperatures (TBs) at a 40° incidence angle were inter-calibrated and the soil moisture (SM) and vegetation optical depth (VOD) were retrieved using the SMAP Dual Channel Algorithm (DCA). The SMAP/SMOS L3 Radiometer 9 km EASE-Grid Soil Moisture (NSIDC-0800) product is generated by the processing software ingesting one day’s worth of granules from both the SMAP SPL2SMP_E product and the SMOS-derived L2 data. The L3 product contains both SMAP and SMOS descending (6:00 AM/PM) and ascending (6:00 PM/AM) data stored in separate arrays.

Get the data

nsidc-0800_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="NSIDC-0800",
    version="1",
    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.