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ASTER Image for AST_09TD

EDG Data Set Name
ASTER On-Demand L2 Surface Radiance TIR

Granule Shortname
AST_09T

Data Set Characteristics
Area: ~60 km x 60 km
Image Dimensions: 700 rows x 830 columns
File Size: ~14 Megabytes
Spatial Resolution: TIR: 90 m
Units:  Surface Radiance: w/m2/sr/µm

Sky Irradiance: w/m2/µm
Projection: Universal Transverse Mercator (UTM)
Data Format: HDF-EOS
GeoTIFF
Vgroup Data Fields:  Surface Radiance: 5

Sky Irradiance: 5

Product Description
The ASTER On-Demand L2 Surface Radiance TIR is an on-demand product generated using the five thermal infra-red (TIR) bands (acquired either during the day or night time) between 8 and 12 µm spectral range. It provides surface-leaving radiance for the TIR bands at 90 meters spatial resolution, which includes both surface-emitted and surface-reflected components. It also provides the down-welling sky irradiance values (in w/m2/µm) for each of the TIR bands. This product is atmospherically corrected, and the surface-leaving radiance is of known accuracy and valid only for clear-sky scenes (cloud-free pixels). This atmospherically corrected product provides the input for generating two other higher-level products: surface spectral emissivity and surface kinetic temperature.

The algorithm to correct atmospheric effects involves 2 elements: 1) It uses a radiative transfer model which is capable of estimating the magnitude of atmospheric emission, absorption, and scattering. It uses Modtran (Moderate Resolution Transmittance Code) radiative transfer model, which calculates atmospheric transmittance and radiance for frequencies from 0 to 50,000 cm-1 at moderate spectral resolution. 2) It identifies and incorporates all the necessary atmospheric parameters applicable to the location and time for which the measurements require correction. These include temperature, water vapor, elevation, ozone, and aerosols.

Surface Radiance (TIR)
Vgroup Data Fields/
Spectral Range (µm)		 Units Data Type Valid Range Band Scale Factor

TIR (90 Meters)
Band 10 (8.125 - 8.475) w/m2/sr/µm 16-bit unsigned integer 0 - 1500 0.006882
Band 11 (8.475 - 8.825) w/m2/sr/µm 16-bit unsigned integer 0 - 1500 0.006780
Band 12 (8.925 - 9.275) w/m2/sr/µm 16-bit unsigned integer 0 - 1500 0.006590
Band 13 (10.25 - 10.95) w/m2/sr/µm 16-bit unsigned integer 0 - 1500 0.005693
Band 14 (10.95 - 11.65) w/m2/sr/µm 16-bit unsigned integer 0 - 1500 0.005225

Sky Irradiance (TIR)
Vgroup Data Fields
Spectral Range (µm)		 Units Data Type Valid Range Band Scale Factor

TIR (90 Meters)
Band 10 (8.125 - 8.475) w/m2/µm 16-bit unsigned integer 0 - 3000 0.006882
Band 11 (8.475 - 8.825) w/m2/µm 16-bit unsigned integer 0 - 3000 0.006780
Band 12 (8.925 - 9.275) w/m2/µm 16-bit unsigned integer 0 - 3000 0.006590
Band 13 (10.25 - 10.95) w/m2/µm 16-bit unsigned integer 0 - 3000 0.005693
Band 14 (10.95 - 11.65) w/m2/µm 16-bit unsigned integer 0 - 3000 0.005225



There are 3 groups of ancillary data inputs used in the atmospheric correction of ASTER radiance and reflectance:

  • Ozone data input: The NCEP/TOVS (National Centers for Environmental Prediction/TIROS (Television & Infrared Observation Satellite) Operational Vertical Sounder) data are acquired from a NOAA satellite, and provides the ancillary column ozone data twice daily. This is the default option. The alternative is the Naval Research Laboratory's (NRL) Ozone Climatology data set
  • Aerosol data input: Presently, NRL's Aerosol Climatology ancillary data are the only available input
  • Temperature, Atmospheric pressure, and Moisture Profile data inputs: The source for these data is the NCEP-GDAS (Global Data Assimilation System) available at a temporal frequency of every six hours. The alternative is the NRL Climatology data set. These data sets are based on modeling, simulation, and prediction, and therefore, they are static, monthly, averaged data sets used only as a last resort.

    • View a Version Formatted for Printing

    Ordering ASTER On-Demand L2 Surface Radiance TIR Product
    The ASTER Surface Radiance TIR product can be ordered through the EOS Data Gateway. The process and procedures for ordering this product are described in the following tutorial: http://lpdaac.usgs.gov/tutorial/. As part of that process, it is necessary to first select an ASTER Level 1A granule from the EOS Data Gateway.

    Product Information
    Release NotesSkip past Product Information Links
    (http://asterweb.jpl.nasa.gov/content/03_data/01_Data_Products/RN_surface_leaving_radiance-TIR.htm)
    ASTER Level-1 Data Products Specification
    (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/ASTER_L1_Product_Spec_Ver_1.3_July01.pdf)
    ASTER User Handbook
    (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/aster_user_guide_v2.pdf)
    ASTER Level-1 Users Guide
    (http://www.science.aster.ersdac.or.jp/en/documnts/users_guide/index.html)
    ASTER Higher-Level Product User Guide
    (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/ASTERHigherLevelUserGuideVer2May01.pdf)
    Algorithm Theoretical Basis Document (ATBD)
    (http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/atbd/docs/ASTER/atbd-ast-09t.pdf)
    ASTER JPL Web Page
    (http://asterweb.jpl.nasa.gov/data_products.asp)
    EOS Data Products Handbook (Volume 1, Revised 2004)
    (http://eospso.gsfc.nasa.gov/ftp_docs/data_products_1.pdf)

    Contact Information
    LP DAAC User Services
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    Last Update: Tuesday, July 01, 2008
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