CLPX-Airborne: Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Data

Summary

This data set consists of apparent surface reflectance, subpixel snow-covered area and grain size inferred from data acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). The AVIRIS has a spectral range of 400-2500 nm, a spectral resolution of 10 nm, instantaneous field of view of 1 mrad, and a scan angle of 15 degrees. Sampling is scene based (~ 815 samples, 512 lines).

The spectral resolution of AVIRIS provides hundreds of spectral bands versus the seven multispectral bands flown on traditional Landsat imaging missions. Through this large number of spectral bands, complex land ecosystems can be imaged and accurately classified.

This data set is part of the NASA Cold Land Processes Field Experiment (CLPX). The NASA CLPX is a multi-sensor, multi-scale experiment that focuses on extending a local-scale understanding of water fluxes, storage, and transformations to regional and global scales. Within a framework of nested study areas in the central Rocky Mountains of the western United States, ranging from 1-ha to 160,000 km2, intensive ground, airborne, and spaceborne observations are collected. Data collection focuses on two seasons: mid-winter, when conditions are generally frozen and dry, and early spring, a transitional period when both frozen and thawed, dry and wet conditions are widespread.

Data are available via FTP.

CAUTIONARY NOTE: These data have not been reviewed for quality. Known issues exist in the processing of these data. Until this disclaimer has been removed, users should send questions and comments about this data set to NSIDC User Services. NSIDC will forward these inquiries to the Principal Investigator for resolution.

Citing These Data

Painter, T. 2002. CLPX-Airborne: Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Data. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

Overview Table

Category	Description
Data format	Apparent surface reflectance: binary, short integer Fractional snow-covered area: binary, floating point (data range N [0.0,1.0]) Subpixel snow grain radius: binary, floating point (data range N [0, 1100 micrometers])
Spatial coverage and resolution	Southernmost Latitude: 39.70 N Northernmost Latitude: 41.00 N Westernmost Longitude: 107.00 W Easternmost Longitude: 105.50 W Coverage is not continuous. Spatial resolution is approximately 1.5 m.
Temporal coverage and resolution	4-8 April 2002; 19-20 Februrary 2003; 25 March-1 April 2003
File naming convention	File names include location names. Reflectance files include ".rfl" in the file name. Radiance files include ".img" in the file name. Grain size files include ".grnsz" in the file name. Snow cover files include ".snow" in the file name.
File size	File sizes range from 2 B to 242 MB. Total distribution volume: 1.1 GB
Parameter(s)	Apparent surface reflectance, subpixel snow-covered area, and grain size
Procedures for obtaining data	Data are available via FTP.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator

Thomas H. Painter
CIRES/National Snow and Ice Data Center
University of Colorado
Boulder, Colorado USA

Technical Contact

2. Detailed Data Description

CAUTIONARY NOTE: These data have not been reviewed for quality. Known issues exist in the processing of these data. Until this disclaimer has been removed, users should send questions and comments about this data set to nsidc@nsidc.org. NSIDC will forward these inquiries to the PI for resolution.

AVIRIS data have the following characteristics:

• Spectral range: 400-2500 nm
• Spectral resolution: 10 nm
• Spatial resolution: 1.5 m (variable)
• Swath width: 1.0 km (variable)
• Processing level: apparent surface reflectance, subpixel snow-covered area and grain size
• Sampling: scene based (~ 815 samples, 512 lines)
• Temporal coverage: April 4-8, 2002; February 19-20, 2003; March 25-April 1, 2003
• Spatial coverage: [39.70N, 1070W] to [410N, 105.50W], not complete coverage

Format

Apparent surface reflectance: binary, short integer
Subpixel snow-covered area: binary, floating point (data range N [0.0,1.0])
Subpixel snow grain radius: binary, floating point (data range N [0, 1100 micrometers])

File and Directory Structure

Data are organized in four directories: one for each of two Intensive Observation Periods (IOP-2 and IOP-4); one directory for "reflectances," and one for "radiances." Within each IOP directory, data files are organized by study area location.

File Naming Convention

The following codes are used in filenames:

File names include location names.
Reflectance files include ".rfl" in the file name.
Radiance files include ".img" in the file name.
Grain size files include ".grnsz" in the file name.
Snow cover files include ".snow" in the file name.
Vegitation cover files include ".veg" in the file name.

Each file is named by its location and then a date of the form yymmdd.

File Size

File sizes range from 2 B to 242 MB.

Spatial Coverage

Southernmost Latitude: 39.70 N
Northernmost Latitude: 41.00 N
Westernmost Longitude: 107.00 W
Easternmost Longitude: 105.50 W

Coverage is not continuous.

Spatial Resolution

Spatial resolution is approximately 1.5 m.

Temporal Coverage

AVIRIS measurements were made on 4-8 April 2002; 19-20 Februrary 2003; and 25 March-1 April 2003.

Parameters or Variables

Apparent surface reflectance

Subpixel snow-covered area

Grain size

Parameter Description

AVIRIS measures calibrated radiance. The data include apparent surface reflectance, subpixel snow-covered area, and grain size.

For a complete description of parameters and measurements, please refer to the Measurements section of the CLPX Plan at http://www.nohrsc.nws.gov/~cline/clp/field_exp/clpx_plan/chapters/CLPX_plan_chap4.htm

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

Total data volume is 1.1 GB.

Related Data Collections

• All CLPX Data Sets

4. Data Acquisition and Processing

For complete information about data acquisition and processing regarding CLPX, please see the Cold Land Processes Field Experiment (CLPX) Plan Web Site at http://www.nohrsc.nws.gov/~cline/clpx.html.

For complete information about data acquisition and processing, please see JPL's AVIRIS Data Facility Web site.

5. References and Related Publications

Please see the References section of the CLPX Plan at http://www.nohrsc.nws.gov/~cline/clp/field_exp/clpx_plan/chapters/CLPX_plan_chap12.htm.

6. Document Information

List of Acronyms

The following acronyms and abreviations are used in this document:

Acronym	Description
AVIRIS	Airborne Visible/Infrared Imaging Spectrometer
CLPX	Cold Land Processes Field Experiment
FTP	File Transfer Protocol
IOP	Intensive Study Period
NASA	National Aeronautics and Space Administration
NSIDC	National Snow and Ice Data Center
URL	Uniform Resource Locator

Document Creation Date

12 April 2006

Document Revision Date

20 August 2007

Document URL

http://nsidc.org/data/docs/daac/nsidc0154_clpx_aviris/index.html