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Full catalog/SPL1BTB_NRT
SPL1BTB_NRT·v105·dataset

Raw microwave brightness readings, live (SMAP)

Near Real-time SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures V105
land NASA NSIDC_CPRD Level 1B active HDF5
In plain English

What it measures. Raw, calibrated microwave brightness readings from SMAP, meaning how much natural microwave energy the Earth's surface gives off as seen by the sensor, listed in order along the satellite's track.

How it's made. Produced from SMAP's L-band microwave radiometer; this near-real-time version is geolocated and calibrated and delivered within about three hours of the satellite passing overhead.

How & where you'd use it. A low-level building-block product mainly feeding into higher-level soil-moisture products. It is aimed at operational, time-sensitive needs; researchers wanting top quality are pointed to the standard, non-rushed version.

What's measured

SPECTRAL/ENGINEERING › MICROWAVE › ANTENNA TEMPERATURESPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › BRIGHTNESS TEMPERATURE

Coverage & cadence

  • Time span2025-06-26 → ongoing
  • Measured bySMAP (SMAP L-BAND RADIOMETER)
  • Processing levelLevel 1B
  • Spatial extent-180, -86.4, 180, 86.4
  • 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 Near Real-Time (NRT) data set corresponds to the standard SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures (SPL1BTB) product. The data provide calibrated estimates of time-ordered geolocated brightness temperature data measured by the Soil Moisture Active Passive (SMAP) passive microwave radiometer, the SMAP L-band radiometer. These Near Real-Time data are available within three hours of satellite observation. The data are created using the latest available ancillary data and spacecraft and antenna attitude data to reduce latency. The SMAP satellite orbits Earth every two to three days, providing half-orbit, ascending and descending, coverage from 86.4°S to 86.4°N in swaths 1000 km across. Data are stored for approximately two to three weeks. Thus, at any given time, users have access to at least fourteen consecutive days of Near Real-Time data through the NSIDC DAAC. Users deciding between the NRT and standard SMAP products should consider the immediacy of their needs versus the quality of the data required. Near real-time data are provided for operational needs whereas standard products meet the quality needs of scientific research. If latency is not a primary concern, users are encouraged to use the standard science product, SPL1BTB (<a href="https://doi.org/10.5067/ZHHBN1KQLI20">https://doi.org/10.5067/ZHHBN1KQLI20</a>).

Get the data

spl1btb_nrt_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SPL1BTB_NRT",
    version="105",
    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.