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These ASTER Level 1B data include three Visible and Near-infrared (VNIR) bands, six Shortwave Infrared (SWIR) bands, and five Thermal Infrared (TIR) bands The data are L1B (radiance) data with geometric and radiometric correction.
Data Set ID:
NSIDC-0197
SMEX02 ASTER Level 1B Data, Iowa, Version 1
This is the most recent version of these data.
BASIC Level of Service
Data: Data integrity verified
Documentation: Key metadata and links to supporting documentation available
User Support: Assistance with data access and basic data usage
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Geographic Coverage |
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Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.
Jackson, T. and M. Cosh. 2003. SMEX02 ASTER Level 1B Data, Iowa, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/KYFJ3QI6YGI2. [Date Accessed].Collapse All / Open All
Detailed Data Description
Investigators acquired a series of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images from the Terra satellite. Three ASTER scenes were mosaicked and the regional study area extracted to form one image for each of ASTER's 14 spectral channels. These data represent a single snapshot; the satellite overpass time was 17:20 GMT on 1 July 2002. The study area is the Walnut Creek Watershed area in Iowa, USA
Format
The data are in unsigned integer binary files in terms of scaled radiance, one file for each band, in PC byte order (little endian). There is no header information included in these files.
VNIR files (bands 1-3) are 3702 columns by 7662 rows.
SWIR files (bands 4-9) are 1852 columns by 3832 rows.
TIR files (bands 10-14) are 618 columns by 1278 rows.
The digit number (DN) was converted to radiance (W/(m2*sr*μm) using the following equation:
Radiance=(DNvalue-1)x unit conversion coefficients.
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File Naming Convention
File names use the following conventions:
ASTER_mmddyyyy_bxx(x).bil
where: mm = month, dd = day, yyyy = year, xx(x) = band number. For example, in the file "ASTER_07012002_b7.bil," data were collected on 1 July 2002 by the SWIR band 7.
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File Size
SWIR files are 13.5 MB, TIR files are 1.5 MB, and VNIR files are 54.1 MB.
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Volume
Total volume is 251 MB.
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Spatial Coverage
Southernmost Latitude: 41.70°N
Northernmost Latitude: 42.73°N
Westernmost Longitude: 93.84°W
Easternmost Longitude: 93.16°W
The following table shows the Universal Transverse Mercator (UTM) geographic locations of the various sensor data. (UTM coordinates are in meters.)
| Sensor | VNIR | SWIR | TIR | |||
|---|---|---|---|---|---|---|
| Easting | Northing | Easting | Northing | Easting | Northing | |
| Upper Left | 431093 E | 4731101 N | 431077 E | 4731113 N | 431076 E | 4731102 N |
| Upper Right | 486608 E | 4731101 N | 486607 E | 4731113 N | 486606 E | 4731102 N |
| Lower Left | 431093 E | 4616186 N | 431077 E | 4616183 N | 431076 E | 4616173 N |
| Lower Right | 486608 E | 4616186 N | 486607 E | 4616183 N | 486606 E | 4616173 N |
Spatial Resolution
VNIR has 15 m resolution, SWIR has 30 m resolution, and TIR has 90 m resolution.
Projection Description
Universal Transverse Mercator (UTM) Zone 15
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Temporal Coverage
Data were collected on 1 July 2002 by the ASTER instrument.
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Parameter or Variable
Parameter Description
The parameters are VNIR, SWIR, and TIR radiance imagery. Three ASTER scenes were mosaicked and the regional study area extracted to form one image for each of ASTER's 14 spectral channels.
Sample Data Record
The following sample shows a portion of the data file "ASTER_07012002_b7.bil."
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Software and Tools
Open these files in an appropriate image processing or image viewing application.
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Data Acquisition and Processing
Sensor or Instrument Description
ASTER is an advanced optical sensor of 14 spectral channels ranging from the visible to thermal infrared region.
The high-resolution VNIR radiometer observes solar radiation reflected from Earth's surface in three visible and near-infrared bands (1-3). The spectral region is 0.52-0.86 μm. VNIR has a pointing capability of +/-24° from nadir in the cross-track direction. The radiometer is calibrated in orbit using halogen lamps.
SWIR is a high-resolution, multispectral radiometer that detects reflected solar radiation from Earth's surface in the wavelength region of 1.6 - 2.43 μm (bands 4-9). SWIR can also change the boresight in the cross-track direction by +/-8.55° from nadir using a pointing mechanism.
TIR is an advanced radiometer with five spectral bands (10-14) in the thermal infrared (8-12 μm).
For more information, please see the ASTER User Guide.
The band spectral range and conversion coefficients are listed in the following table.
| Sensor | Band Number | Spectral Range (μm) | Unit Conversion Coefficient (W/(m2*sr*μm)/DN) |
|---|---|---|---|
| VNIR | 1 | 0.52-0.60 | 0.676 |
| 2 | 0.63-0.69 | 0.708 | |
| 3N | 0.78-0.86 | 0.862 | |
| SWIR | 4 | 1.60-1.70 | 0.2174 |
| 5 | 2.145-2.185 | 0.0696 | |
| 6 | 2.185-2.225 | 0.0625 | |
| 7 | 2.235-2.285 | 0.0597 | |
| 8 | 2.295-2.365 | 0.0417 | |
| 9 | 2.360-2.430 | 0.0318 | |
| TIR | 10 | 8.125-8.475 | 0.006822 |
| 11 | 8.475-8.825 | 0.006780 | |
| 12 | 8.925-9.275 | 0.006590 | |
| 13 | 10.25-10.95 | 0.005693 | |
| 14 | 10.95-11.65 | 0.005225 |
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References and Related Publications
Contacts and Acknowledgments
Thomas J. Jackson, Hydrologist, Michael H. Cosh, General Physical Scientist, and Lynn McKee, Soil Scientist, USDA ARS Hydrology Lab.
Document Information
DOCUMENT CREATION DATE
November 2003
No technical references available for this data set.
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