First PREFIRE Datasets Released | NASA Earthdata

The new Level 1 through Level 3 products, which were released earlier this month, advance the mission’s goals by providing space-based measurements of radiative fluxes, cloud masks, spectrally variant surface emissivity, and column water vapor, with the requisite coverage during diurnal and seasonal cycles and the resolution necessary to capture surface and cloud variability. 

“Far-infrared radiation (wavelengths between 15 to 100 micrometers) plays a crucial role in Earth’s energy budget. It affects the outgoing longwave radiation and is vital for understanding the heat exchange between Earth’s surface and the atmosphere, especially in polar regions,” said ASDC scientist Dr. Hazem Mahmoud. “Despite its importance, this portion of the spectrum has not been comprehensively or systematically measured pole to pole. Understanding the seasonal variations in FIR is essential for improving Earth system models, which are key to enhancing projections of future environmental scenarios.”

This is what makes this first release of PREFIRE data so significant, says Mahmoud. Researchers around the globe now have the opportunity to access these critical infrared spectral measurements from space, thereby allowing them to study polar processes and variations with greater precision.

“The significance of this new release is substantial. For the first time, a wide-ranging dataset of Level 1, 2, and 3 data products from PREFIRE is available. This consolidates the raw measurements (Level 1), derived geophysical variables (Level 2), and monthly global aggregations (Level 3) into a single, accessible resource,” he said. “This release is not only a technical achievement for the mission, but it also enables collaboration across the scientific community. Since the launch of the mission, users from more than 17 countries around the world have downloaded PREFIRE data, underscoring its international scientific value.”

See below for details about the PREFIRE datasets released by the ASDC.

Level 1A Datasets

Note: Geographic coverage for both of these Level 1A datasets is global, with the greatest concentration of data in the polar regions. Given that these datasets are not geolocated, PREFIRE_SAT1_1A-RAD and PREFIRE_SAT2_1A-RAD will require geolocation for direct scientific study.

Level 1B Datasets

Note: Geographic coverage for both of these Level 1B datasets is global, with the greatest concentration of data in the polar regions. 

Level 2B Datasets 

Level 3 Datasets

Auxiliary Datasets

All Level 1, 2, and 3 and Auxiliary PREFIRE data products are produced by the PREFIRE Science Data Processing System (SDPS), located at the University of Wisconsin-Madison, and archived by ASDC at NASA’s Langley Research Center. Each of the files from these data products is created in netCDF4 format with standard metadata. Level 1A and 1B Radiance (1A-RAD, 1B-RAD) data products are nominally processed on a delay of at least four days from ingest of the Level 0 science data, allowing for data sent from the spacecraft out of chronological order to be incorporated. The AUX-MET data products require the observational ground footprint information from the 1B-RAD granules and are therefore nominally processed just after the 1B-RAD data product granules are produced.

About the PREFIRE Mission

The Arctic plays a crucial role in regulating Earth’s energy balance by venting excess energy received in the tropics. Nearly 60 percent of Arctic emission occurs at FIR wavelengths longer than 15 microns (μm), yet they have never been systematically or spectrally measured. PREFIRE aims to correct this by quantifying the spatial and temporal variability in spectral FIR emissions, thereby informing assessments of their impact on the atmospheric energy retention effect.

The PREFIRE mission is comprised of two space-based TIRS instruments aboard two small 6U cube-shaped satellites (known as CubeSats) circumnavigating Earth in near-polar orbit. As they travel around the globe, the CubeSats sample Arctic and Antarctic surfaces and clouds, capturing multiple observations of those regions each day. Initially planned for 10 months of operation, NASA’s Jet Propulsion Laboratory (JPL), which manages the mission, announced that PREFIRE has been extended through September 2026. This extension will allow for continued data collection and enhanced understanding of polar surface and cloud dynamics over time.

PREFIRE CubeSats represent an advance in spaceborne technology. These compact satellites are equipped with cutting-edge sensors capable of detecting FIR—a crucial indicator of polar energy emission efficiency—with a spectral ranger covering wavelengths from 5 to 54 μm, capturing a wide range of thermal emissions.

Further, in concert with other Earth-observing satellites operated by NASA and its international partners, data from the PREFIRE CubeSats can be combined with those from other satellites, such as the Gravity Recovery and Climate Experiment (GRACE), to further enhance the understanding of polar climate processes that have global implications.

“With these data, scientists can better pinpoint how and where energy is lost in the polar regions—information that’s vital for understanding sea ice dynamics, permafrost changes, and the broader implications of a warming planet,” said Mahmoud. “Ultimately, the refined climate models that stem from PREFIRE data will help inform future projections and guide policy decisions related to polar and global Earth systems.”

Data Access and Visualization

Data from the PREFIRE mission are available from the ASDC website as well as through NASA’s Earthdata Search. To view video tutorials demonstrating how users can search, access, and download archived PREFIRE data, see the “ASDC Data Access” tab on this ASDC-produced PREFIRE StoryMap. NASA Worldview allows you to visualize and download a wide variety of Earth science data, including PREFIRE data. The Worldview interface allows users to select their desired data layers and timeframe, and then download the data for research and analysis.

Related Learning Resources