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EDG Data Set Name
ASTER On-Demand L2 Brightness Temperature at the Sensor

Granule Shortname
AST_04

Data Set Characteristics
Area: ~60 km x 60 km
Image Dimensions: 700 rows x 830 columns
File Size: ~7 Megabytes
Spatial Resolution: 90 m
Units: Centigrade (C°)
Projection: Universal Transverse Mercator (UTM)

Data Format:	HDF-EOS
	GeoTIFF

Vgroup Data Fields: Surface Radiance: 5

Product Description
The ASTER On-Demand L2 Brightness Temperature at the Sensor is an on-demand product generated using the five thermal infrared bands between 8 and 12 µm. Brightness temperature is the apparent temperature of the imaged surface assuming a surface emissivity of 1.0 or that of a blackbody. However, this Brightness Temperature at Sensor product, as the name implies, entirely ignores atmospheric effects. The radiance at the sensor is the integral over the instrument response function of the emissivity, times the blackbody radiance. Spectral emissivity and temperature are the unknowns in this equation. The Brightness Temperature algorithm converts the radiance values in the L1B into corresponding brightness temperatures values by setting the emissivity to one (1), which is based on the assumption that the target is a blackbody. Brightness temperature is therefore defined as the temperature that a blackbody would be in order to produce the radiance perceived by the sensor. The output product is a five-band data set in units of degrees centigrade, scaled by a factor of 100. Brightness temperature is used, for instance, to observe volcanic ash clouds and also in detecting ice leads in the Arctic.

Vgroup Data Fields/ Spectral Range (microns)	Units	Data Type	Valid Range	Band Scale Factor
TIR (90 Meters)
Band 10 (8.125 - 8.475)	C°	16-bit signed integer	-27315 to +5500	0.01
Band 11 (8.475 - 8.825)	C°	16-bit signed integer	-27315 to +5500	0.01
Band 12 (8.925 - 9.275)	C°	16-bit signed integer	-27315 to +5500	0.01
Band 13 (10.25 - 10.95)	C°	16-bit signed integer	-27315 to +5500	0.01
Band 14 (10.95 - 11.65)	C°	16-bit signed integer	-27315 to +5500	0.01

View a Version Formatted for Printing

Ordering ASTER On-Demand L2 Brightness Temperature at the Sensor
The ASTER Brightness Temperature at the Sensor 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_brightness_temperature_2_5.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/BTS_ATBD.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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