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Full catalog/PREFIRE_SAT1_2B-SFC_COG11um
PREFIRE_SAT1_2B-SFC_COG11um·vR01·dataset

How well polar surfaces radiate heat, 11 micron (PREFIRE-1)

Polar Radiant Energy in the Far InfraRed Experiment (PREFIRE) Surface Emissivity from PREFIRE Satellite 1 COG11um R01
atmosphere NASA LARC_CLOUD Level 2B active TIFF
In plain English

What it measures. How efficiently polar surfaces — ice, snow, land — give off heat as infrared light at about 11 microns, a property that affects how much energy escapes to space from the coldest parts of the planet.

How it's made. Retrieved from the PREFIRE TIRS infrared spectrometer aboard one of two small PREFIRE CubeSats, by combining its raw radiance with a cloud mask and weather data through a radiative-transfer calculation, available only for clear skies.

How & where you'd use it. Helps fill a long-standing gap in measuring polar heat loss, feeding climate and circulation models so they can better project future conditions in the Arctic and Antarctic.

What's measured

ATMOSPHERE › ATMOSPHERIC RADIATION › EARTH RADIATION BUDGETATMOSPHERE › ATMOSPHERIC RADIATION › LONGWAVE RADIATION › UPWELLING LONGWAVE RADIATIONLAND SURFACE › SURFACE RADIATIVE PROPERTIES › EMISSIVITY

Coverage & cadence

  • Time span2024-07-24 → ongoing
  • Measured byPREFIRE-SAT1 (TIRS-PREFIRE)
  • Processing levelLevel 2B
  • Spatial extent-180, -90, 180, 90
  • FormatsTIFF
  • StatusACTIVE

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

Polar Radiant Energy in the Far InfraRed Experiment (PREFIRE) Surface Emissivity from PREFIRE Satellite 1 COG11um (PREFIRE_SAT1_2B-SFC_COG11um) is retrieved from data collected by the PREFIRE Thermal Infrared Spectrometer (TIRS-PREFIRE) aboard PREFIRE-SAT1. Dual CubeSats each carry a PREFIRE Thermal Infrared Spectrometer (TIRS-PREFIRE), a push broom spectrometer with 63 channels measuring mid- and far-infrared (FIR) radiation from approximately 5 to 53 µm. Most polar emissions are in the FIR but have not been measured on a large scale. PREFIRE aims to fill knowledge gaps in the global energy budget by more accurately characterizing polar emissions. This information will then be assimilated into global circulation and other models to predict future conditions more accurately. PREFIRE_SAT1_2B-SFC_COG11um contains Cloud-Optimized GeoTIFF (COG) files that each contain a georeferenced rendering of retrieved surface emissivity values for channel 14 (centered at about 11.4 µm). Those surface emissivity data values are computed from a single granule of PREFIRE Spectral Radiance (PREFIRE_SAT1_1B-RAD) data using an Optimal Estimation retrieval via a radiative transfer model with inputs from PREFIRE_SAT1_2B-MSK (cloud mask), and PREFIRE_SAT1_AUX-MET. The retrieved surface emissivity values are only available for clear-sky conditions. As part of the rendering process, mean retrieved surface emissivity values are computed for a global grid of raster elements (each approximately 2.23 km in width), based on which raster elements each PREFIRE ground footprint overlaps. This procedure is done in order to better visualize the PREFIRE data despite substantial overlap of adjacent along-track ground footprints – but it is important to remember that the individual PREFIRE ground footprints are much bigger (by about 80x, in terms of area) than each of the GeoTIFF raster elements. These cloud-optimized GeoTIFF images may be viewed using many geographic information systems (GIS), such as the freely available QGIS. Science data retrieval started July 24, 2024 and is ongoing. Currently, the geographic coverage is for latitudes between approximately 60° to 84° in both polar regions, although future releases may include data for all latitudes equatorward of about 84°. Within the orbital swath there are eight distinct tracks of data associated with the eight separate spatial scenes for each TIRS-PREFIRE. At the beginning of the mission, the approximate scene footprint sizes were 11.8 km x 34.8 km (cross-track x along-track), with gaps between each scene of approximately 24.2 km. The entire swath was about 264 km across. Note that the scene footprint and swath sizes quoted here are for the orbit altitude soon after launch. However, the footprint and swath sizes will slowly become smaller as the orbit altitude decreases with time. Similar surface emissivity GeoTIFF renderings for the sister instrument aboard PREFIRE-SAT2 can be found in the PREFIRE_SAT2_2B-SFC_COG11um collection.

Get the data

prefire_sat1_2b-sfc_cog11um_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="PREFIRE_SAT1_2B-SFC_COG11um",
    version="R01",
    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 LARC_CLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.