How wet the soil is (SMAP radar, daily, 3 km) — SPL3SMA

In plain English

What it measures. How wet the soil is across the world's land surfaces, estimated daily at a fine 3 km scale.

How it's made. Retrieved from the radar on NASA's SMAP satellite plus supporting data, then mapped onto a global equal-area grid.

How & where you'd use it. Soil moisture matters for farming, drought monitoring, flood forecasting, and understanding how water cycles between land and air.

What's measured

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

Coverage & cadence

Time span2015-04-13 → 2015-07-07
Measured bySMAP (SMAP L-BAND RADAR)
Processing levelLevel 3
Spatial extent-180, -85.044, 180, 85.044
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

This Level-3 (L3) soil moisture product provides a composite of daily estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) radar as well as a variety of ancillary data sources. SMAP L-band soil moisture data are resampled to an Earth-fixed, global, cylindrical 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0).

Get the data

spl3sma_access.py

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

results = earthaccess.search_data(
    short_name="SPL3SMA",
    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.

Official links

Search and order NASA Earth Science data using spatial and temporal filters. Reformatting, reprojecting, and subsetting options are available for some data sets. GET DATA
Quickly download a few files using a web browser, or access data through a command-line utility such as WGET. GET DATA
Search data by spatial and/or temporal ranges or file name. Choose from various download options, including a Python script. GET DATA
A Python library to search and access NASA Earth science data with just a few lines of code GET DATA
Find more data access options and help resources. VIEW RELATED INFORMATION
SMAP L3 Radar Global Daily 3 km EASE-Grid Soil Moisture, Version 3 User Guide VIEW RELATED INFORMATION
SMAP Post-Recovery Advisory Note 23 July 2019 VIEW RELATED INFORMATION
SPL2/3SMA Assessment Report Version 4 [2017] VIEW RELATED INFORMATION