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Description
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Level 1A (AST_L1A) contains reconstructed, instrument digital numbers (DNs) derived from the acquired telemetry streams of the telescopes: Visible and Near Infrared (VNIR), Shortwave Infrared (SWIR), and Thermal Infrared (TIR). Additionally, geometric correction coefficients and radiometric calibration coefficients are calculated and appended to the metadata but not applied. The AST_L1A product has a spatial resolution of 15 meters (m) for the VNIR bands, 30 m for the SWIR bands, and 90 m for the TIR bands.
Known Issues
TIR bands: Acquisitions for TIR bands ended on January 16, 2026, at 05:10:45 UTC, when the ASTER TIR instrument was permanently turned off due to power limitations on the Terra spacecraft. More information is available in this NASA Science News Brief.
Data acquisition gaps: On November 28, 2024, one of Terra's power-transmitting shunt units failed. As a result, there was insufficient power to maintain functionality of the ASTER instrument. ASTER resumed acquisitions for the VNIR bands on January 18, 2025, and for the TIR bands on April 15, 2025. Users should note the data gap in ASTER acquisitions from November 28, 2024, through January 16, 2025, for VNIR observations, and a gap from November 28, 2024, through April 15, 2025, for TIR acquisitions.
SWIR bands: ASTER SWIR detectors are no longer functioning as of January 12, 2009, due to anomalously high SWIR detector temperatures.
SWIR anomaly: Users are advised that ASTER SWIR data acquired from April 2008 to January 11, 2009, exhibit anomalous saturation of values and anomalous striping. This effect is also present for some prior acquisition periods. Please refer to the ASTER SWIR User Advisory for more details.
15 Meters x 15 Meters 30 Meters x 30 Meters 90 Meters x 90 Meters
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2000-03-04 to Present
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
,
Ground Data System, Japan Space Systems, National Institute of Advanced Industrial Science and Technology, Ministry of Economy, Trade, and Industry, Japan (JP/METI/AIST/JSS/GDS)
Concept ID
C3306888985-LPCLOUD
Data State
ACTIVE
Number of Files/Granules
4889533
Processing Level
1A
Published
Updated
Science Keywords
Reflected Infrared
,
Thermal Infrared
,
VISIBLE IMAGERY
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
Copy Citation
Citation Copied
NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team. (2025). ASTER L1A Reconstructed Unprocessed Instrument Data V004 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/ASTER/AST_L1A.004
Date Accessed: 2026-11-10
@misc{NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team_2025,
title={ASTER L1A Reconstructed Unprocessed Instrument Data V004},
url={https://www.earthdata.nasa.gov/data/catalog/lpcloud-ast-l1a-004},
DOI={10.5067/ASTER/AST_L1A.004},
publisher={NASA Land Processes Distributed Active Archive Center},
author={NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team},
year={2025},
}
NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team. “ASTER L1A Reconstructed Unprocessed Instrument Data V004.” NASA Land Processes Distributed Active Archive Center, 2025. doi:10.5067/ASTER/AST_L1A.004.
Date Accessed: 2026-11-10
NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team. “ASTER L1A Reconstructed Unprocessed Instrument Data V004.” NASA Land Processes Distributed Active Archive Center, 2025, https://doi.org/10.5067/ASTER/AST_L1A.004.
Date Accessed: 2026-11-10
File Naming Convention
AST_L1A_00401232021224134_20250912130909.hdf
The file name begins with the Product Short Name (AST_L1A), followed by the 3-digit Version Number plus the Date and Time of Acquisition designated as MMDDYYYYHHMMSS (00401232021224134), Date and Time of Processing designated as YYYYMMDDHHMMSS (20250912130909), and the Data Format (hdf).
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The table below lists the variables contained within a single granule for this
dataset. Variables often contain observed or derived geophysical measurements
collected from a variety of sources, including remote sensing instruments on
satellite and airborne platforms, field campaigns, in situ measurements, and
model outputs. The terms variable, parameter, scientific data set, layer, and band
have been used across NASA’s Earth science disciplines; however, variable is the
designated nomenclature in NASA’s Common Metadata Repository (CMR).
Variable metadata attributes such as Name, Description, Units, Data Type, Fill
Value, Valid Range, and Scale Factor allow users to efficiently process and analyze
the data. The full range of attributes may not be applicable to all variables.
Additional information on variable attributes is typically available in the data,
user guide, and/or other product documentation.
For questions on a specific variable, please use the Earthdata Forum.