Close

Service Interruption



SMEX02 Airborne GPS Bistatic Radar Data, Iowa

View Catalog Page


Identification Information:

Dataset Identifier:

NSIDC-0275

Citation:

Citation Information:

Originator: Masters, D.
Publication Date: 20050811
Title: SMEX02 Airborne GPS Bistatic Radar Data, Iowa
Publication Information:
Publication Place: Boulder, Colorado USA
Publisher: CCAR: University of Colorado, Colorado Center for Astrodynamics Research
Online Linkage: http://nsidc.org/data/nsidc-0275.html

Description:

Abstract:

This data set contains measurements of Global Positioning System (GPS) signals reflected from the Earth’s surface and collected on an airborne platform. The measurements were taken over the Soil Moisture Experiments 2002 (SMEX02) Walnut Creek Watershed area in Iowa, USA. The reflections collected were from flat agricultural land with mostly corn and soybean crops in mid-development. Data were collected on 19, 25, 27 June 2002 and 1, 2, 5-8 July 2002.

The data are categorized by campaigns and dates, and are processed into levels. Level “0” files are text files directly from the receiver. Levels above “0” are output in Hierarchical Data Format (HDF) format, ordered in UTC time and gzipped. The HDF files contain metadata in the form of attributes that describe the data seta and variables. The variables also contain attributes to self-describe the individual data pieces.

A modified GPS Delay Mapping Receiver (DMR) tracks and measures the direct, line-of-sight, right hand circularly polarized (RHCP) signal of a GPS satellite. It also simultaneously measures the delayed, Earth- reflected, near-specular, left hand circularly polarized (LHCP) GPS signal. The DMR was mounted on the NCAR C-130 along with the Jet Propulsion Laboratory (JPL) Passive and Active L- and S-band (PALS) microwave instrument. GPS signal reflections were collected using the standard hemispherical RHCP antenna mounted on the roof of the aircraft, and a reversed polarization LHCP hemispherical antenna mounted on the belly. The receiver position is computed from either an external navigation source or the receiver's own GPS navigation solution, whichever is more accurate. The GPS surface reflections are georeferenced to a composite Earth consisting of the WGS-84 ellipsoid, the EGM96 geoid, and the GTOPO30 elevation model.

The primary objective was to collect land reflections for sensitivity of the reflected GPS power to temporal and spatial soil moisture and foliage attenuation. The measurements are a form of bistatic radar and can be used to estimate the surface scattering coefficient (roughness and/or dielectric properties) and path delays between the direct and reflected GPS signals. Scattering coefficients can be used to estimate changes in surface soil moisture.

These data were collected as part of a validation study for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). AMSR-E is a mission instrument launched aboard NASA's Aqua Satellite on 04 May 2002. AMSR-E validation studies linked to SMEX are designed to evaluate the accuracy of AMSR-E soil moisture data. Specific validation objectives include assessing and refining soil moisture algorithm performance; verifying soil moisture estimation accuracy; investigating the effects of vegetation, surface temperature, topography, and soil texture on soil moisture accuracy; and determining the regions that are useful for AMSR-E soil moisture measurements.

Purpose: scientific research

Time Period of Content:

Time Period Information:

Range of Dates/Times:

Beginning Date: 20020619
Ending Date: 20020708

Currentness Reference: publication date

Status:

Progress: In work
Maintenance and Update Frequency: Unknown

Spatial Domain:

Bounding Coordinates:

 

West Bounding Coordinate: -93.8°
East Bounding Coordinate: -93.4°
North Bounding Coordinate: 42.005°
South Bounding Coordinate: 41.915°

Keywords:

Theme:

Theme Keyword Thesaurus: NASA Global Change Master Directory (GCMD) Science Keywords
Theme Keyword: EARTH SCIENCE Spectral/Engineering Radar Radar Imagery

Theme:

Theme Keyword Thesaurus: NASA Global Change Master Directory (GCMD) Project Keywords
Theme Keyword: ISMEX Iowa Soil Moisture Experiment
Theme Keyword: SMEX02 Soil Moisture Experiments in 2002

Theme:

Theme Keyword Thesaurus: NASA Global Change Master Directory (GCMD) Instrument Keywords
Theme Keyword: GPS RECEIVERS

Theme:

Theme Keyword Thesaurus: NASA Global Change Master Directory (GCMD) Platform Keywords
Theme Keyword: GPS Global Positioning System Satellites

Theme:

Theme Keyword Thesaurus: None
Theme Keyword: bistatic radar
Theme Keyword: GPS
Theme Keyword: Soil Moisture
Theme Keyword: Surface Roughness

Place:

Place Keyword Thesaurus: NASA Global Change Master Directory (GCMD) Location Keywords
Place Keyword: Continent North America United States Of America

Access Constraints:

None

Use Constraints:

These data are considered exploratory. The techniques to estimate geophysical parameters from these data are being continuously refined. Usage of these data is granted without restriction, but acknowledgment of the source and PI is appreciated.

Point of Contact:

Contact Information:

Contact Person Primary:

Contact Person: Dallas Masters
Contact Organization: University of Colorado, University of Colorado

Contact Address:

Address Type: mailing
Address:
  • University of Colorado
  • CB 431/ CCAR
City: Boulder
State or Province: CO
Postal Code: 80309-0431
Country: USA

Contact Voice Telephone: 1 303 492.4075
Contact Facsimile Telephone: 1 303 492.2825

Back to Top


Distribution Information:

Distributor:

Contact Information:

Contact Organization Primary:

Contact Organization: National Snow and Ice Data Center
Contact Person: NSIDC User Services

Contact Address:

Address Type: mailing
Address:
  • National Snow and Ice Data Center
  • CIRES, 449 UCB
  • University of Colorado
City: Boulder
State or Province: CO
Postal Code: 80309-0449
Country: USA

Contact Voice Telephone: 1 303 492-6199
Contact Facsimile Telephone: 1 303 492-2468
Contact Electronic Mail Address: nsidc@nsidc.org

Resource Description:

NSIDC-0275

Distribution Liability:

NSIDC cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NSIDC makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Back to Top


Metadata Reference Information:

Metadata Date:

20131010

Metadata Review Date:

20131010

Metadata Contact:

Contact Information:

Contact Person Primary:

Contact Person: NSIDC User Services
Contact Organization: National Snow and Ice Data Center

Contact Address:

Address Type: mailing
Address:
  • National Snow and Ice Data Center
  • CIRES, 449 UCB
  • University of Colorado
City: Boulder
State or Province: CO
Postal Code: 80309-0449
Country: USA

Contact Voice Telephone: 1 303 492-6199
Contact Facsimile Telephone: 1 303 492-2468
Contact Electronic Mail Address: nsidc@nsidc.org

Metadata Standard Name:

FGDC Content Standard for Digital Geospatial Metadata: Extensions for Remote Sensing Metadata

Metadata Standard Version:

FGDC-STD-012-2002

Back to Top

Metadata Views

FGDC Text-Only

Federal Geographic Data Committee (FGDC) in plain text

FGDC XML

Federal Geographic Data Committee (FGDC) in Extensible Markup Language (XML)

DIF HTML

NASA Global Change Master Directory (GCMD) Directory Interchange Format (DIF)

ISO HTML

International Organization for Standardization (ISO) 19115:2003 Geographic Information Metadata