ASTER On-Demand L2 Polar Surface and Cloud Classification


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ASTER Image for AST_13POL

EDG Data Set Name
ASTER On-Demand L2 Polar Surface and Cloud Classification

Granule Shortname
AST13POL

Data Set Characteristics

Area: ~60 km x 60 km

Image Dimensions: 4200 rows x 4980 columns

File Size: ~42 MB

Output Image Resolution: 30 meters

Units: Thematic

Projection: Universal Transverse Mercator (UTM)

Data Format: HDF-EOS

Vgroup Data Fields: 1

Product Description
The ASTER On-Demand L2 Polar Surface and Cloud Classification is an on-demand product that provides a classification map discriminating between different surface and cloud features over polar areas. The primary aim of this product is to classify the cloud and snow-ice spectral signatures in both the visible and infrared wavelengths. Presently this algorithm is designed to work with data acquired during the daytime, and there subsequently will be a version that works with the nighttime data.

This product will be especially useful for those studying greenhouse forcings in the polar regions where cloud cover exerts its effects on sea ice conditions, the regional ice-albedo feedbacks, the polar heat balance, and surface melting. This product may also be used in cross-validating the MODIS cloud optical thickness and effective particle sizes, both of which impact the Earth's radiative budget.

The algorithm is hierarchical and is executed in four stages: In the first stage, the VNIR data are sub-sampled by half (15 m to 30 m) while the TIR data are sampled three times (90 m to 30 m). The SWIR data at 30 m are retained in their original resolution. The VNIR and SWIR DNs are normalized for solar irradiance, solar zenith angle, observation angle, and calibration coefficients. The TIR DNs are converted to temperature. In the second stage, the data are pre-classified to reduce the class ambiguity of a pixel's feature vector by using key features like coastline data, land-water mask etc. The third stage involves the use of a back-propagation neural network to aid in the resolution of feature vectors to one of nine possible classes. In the fourth stage, a spatial consistency test is performed on the classification mask, and pixels deemed spatially inconsistent with their neighbors are re-classified.

The final product is a coded pixel map containing the following thematic classes:

View a Version Formatted for Printing

Ordering ASTER On-Demand L2 Polar Surface and Cloud Classification Product
The ASTER Polar Surface and Cloud Classification 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 Notes
(http://asterweb.jpl.nasa.gov/content/03_data/01_Data_Products/release_Polar_Cloud_Class.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-13.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
U.S. Geological Survey (USGS)
Earth Resources Observation and Science Center (EROS)
47914 252nd Street
Sioux Falls, SD 57198-0001

Phone: 605-594-6116

Toll Free: 866-573-3222

866-LPE-DAAC

Fax: 605-594-6963

Email: LPDAAC@eos.nasa.gov

Web: http://LPDAAC.usgs.gov

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URL: http://LPDAAC.usgs.gov/aster/ast_13pol.asp
Technical Contact: LPDAAC@eos.nasa.gov
Last Update: Monday, February 05, 2007
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