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EDG Data Set Name
ASTER On-Demand L2 Surface Emissivity

Granule Shortname
AST_05

Data Set Characteristics
Area: ~60 km x 60 km
Image Dimensions: 700 rows x 830 columns
File Size: ~9 Megabytes
Spatial Resolution: 90 m
Units: None
Projection: Universal Transverse Mercator (UTM)

Data Format:	HDF-EOS
	GeoTIFF

Vgroup Data Fields: Surface Radiance: 5

Product Description
The ASTER On-Demand L2 Surface Emissivity is an on-demand product generated using the five thermal infrared (TIR) bands (acquired either during the day or night time) between 8 and 12 µm spectral range. It contains surface emissivity over the land at 90 meters spatial resolution. Estimates of surface emissivity were thus far only derived using surrogates such as land-cover type or vegetation index. The Temperature/Emissivity Separation (TES) algorithm is used to derive both E (emissivity) and T (surface temperature). The main goals of the TES algorithm include: recovering accurate and precise emissivities for mineral substrates, and estimating accurate and precise surface temperatures especially over vegetation, water and snow.

The TES algorithm is executed in the ASTER processing chain following generation of ASTER Level-2 Surface Radiance (TIR). The land-leaving radiance and down-welling irradiance vectors for each pixel are taken in account. Emissivity is estimated using the Normalized Emissivity Method (NEM), and is iteratively compensated for reflected sunlight. The emissivity spectrum is normalized using the average emissivity of each pixel. The minimum-maximum difference (MMD) of the normalized spectrum is calculated and estimates of the minimum emissivity derived through regression analysis. These estimates are used to scale the normalized emissivity and compensate for reflected skylight with the derived refinement of emissivity.

View a Version Formatted for Printing

Ordering ASTER On-Demand L2 Emissivity Product
The ASTER Emissivity 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_surface_emissivity_product.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-05-08.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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