Earth Data School
About
Full catalog/SPL1CTB_E
SPL1CTB_E·v004·dataset

Microwave brightness for soil and water, sharpened (SMAP, 9 km)

SMAP Enhanced L1C Radiometer Half-Orbit 9 km EASE-Grid Brightness Temperatures V004
land NASA NSIDC_CPRD Level 1C active HDF5
In plain English

What it measures. How much natural microwave energy the surface gives off (brightness temperature), which reveals things like soil wetness and water. Readings are sharpened to bring out finer detail.

How it's made. Collected by the radiometer on NASA's SMAP satellite during its dawn and dusk passes, then refined with an interpolation technique and placed on a 9-km global grid.

How & where you'd use it. A calibrated input mainly used to build soil-moisture and freeze/thaw products; researchers studying land, water, and ice can also use the brightness measurements directly.

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 enhanced 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 Level-1B (L1B) interpolated antenna temperatures. Backus-Gilbert optimal interpolation techniques are used to extract enhanced information from SMAP antenna temperatures before they are converted to brightness temperatures. The resulting brightness temperatures are posted to an Earth-fixed, 9 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.

Get the data

spl1ctb_e_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SPL1CTB_E",
    version="004",
    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.