Raw microwave brightness for soil and weather (SMAP, 36 km)

In plain English

What it measures. Holds calibrated, location-tagged microwave brightness temperatures, essentially how much natural microwave energy the surface emits, mapped onto a 36 km global grid from the satellite's dawn and dusk passes.

How it's made. Created by taking SMAP's L-band radiometer measurements and resampling them onto an equal-area grid in several map projections (Level-1C).

How & where you'd use it. A building-block input rather than a finished product; it feeds the derived soil moisture data most users rely on.

What's measured

SPECTRAL/ENGINEERING › MICROWAVE › BRIGHTNESS TEMPERATURE

Coverage & cadence

Time span2015-03-31 → ongoing
Measured bySMAP (SMAP L-BAND RADIOMETER)
Processing levelLevel 1C
Spatial extent-180, -85.044, 180, 85.044
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-1C (L1C) product contains calibrated and geolocated brightness temperatures acquired by the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP L-band Level-1B time-ordered brightness temperatures resampled to an Earth-fixed, 36 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in three projections: global cylindrical, Northern Hemisphere azimuthal, and Southern Hemisphere azimuthal. This L1C product is a gridded version of the SMAP time-ordered Level-1B radiometer brightness temperature product.

Get the data

spl1ctb_access.py

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

results = earthaccess.search_data(
    short_name="SPL1CTB",
    version="006",
    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.

What's measured

Coverage & cadence

What you can do with it

Get the data

Official links