Entry_ID: NSIDC-0275
Entry_Title: SMEX02 Airborne GPS Bistatic Radar Data, Iowa
Group: Data_Set_Citation
   Dataset_Creator: Masters, D. 
   Dataset_Title: SMEX02 Airborne GPS Bistatic Radar Data, Iowa
   Dataset_Release_Date: 2005-08-11
   Dataset_Release_Place: Boulder, Colorado USA
   Dataset_Publisher: CCAR: University of Colorado, Colorado Center for Astrodynamics Research
   Online_Resource: http://nsidc.org/data/nsidc-0275.html
End_Group
Group: Personnel
   Role: Investigator
   First_Name: Dallas
   Last_Name: Masters
   Phone: 1 303 492.4075 
   Fax: 1 303  492.2825 
   Group: Contact_Address
      Address: University of Colorado
      Address: University of Colorado
      Address: University of Colorado
      Address: CB 431/ CCAR
      City: Boulder
      Province_or_State: CO
      Postal_Code: 80309-0431
      Country: USA
   End_Group
End_Group
Group: Personnel
   Role: Investigator
   First_Name: Dallas
   Last_Name: Masters
   Phone: 1 303 492.4075 
   Fax: 1 303  492.2825 
   Group: Contact_Address
      Address: University of Colorado
      Address: University of Colorado
      Address: University of Colorado
      Address: CB 431/ CCAR
      City: Boulder
      Province_or_State: CO
      Postal_Code: 80309-0431
      Country: USA
   End_Group
End_Group
Group: Personnel
   Role: Investigator
   First_Name: Stephen
   Last_Name: Katzberg
   Group: Contact_Address
      Address: NASA Langley Research Center
      Address: M.S. 328
      Address: NASA-Langley Research Center
      City: Hampton
      Province_or_State: VA
      Postal_Code: 23681-0001
   End_Group
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Spectral/Engineering
   Term: Radar
   Variable_Level_1: Radar Imagery
End_Group
Keyword: bistatic radar
Keyword: GPS
Keyword: Soil Moisture
Keyword: Surface Roughness
Sensor_Name: GPS RECEIVERS
Source_Name: GPS > Global Positioning System Satellites
Group: Temporal_Coverage
   Start_Date: 2002-06-19
   Stop_Date: 2002-07-08
End_Group
Data_Set_Progress: in work
Group: Spatial_Coverage
   Southernmost_Latitude: 41.915
   Northernmost_Latitude: 42.005
   Westernmost_Longitude: -93.8
   Easternmost_Longitude: -93.4
End_Group
Group: Location
   Location_Category: CONTINENT
   Location_Type: NORTH AMERICA
   Location_Subregion1: UNITED STATES OF AMERICA
End_Group
Project: SMEX02 > Soil Moisture Experiments in 2002
Project: ISMEX > Iowa Soil Moisture Experiment
Group: 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.

End_Group
Data_Set_Language: English
Group: Data_Center
   Data_Center_Name: NASA DAAC > NASA DAAC at the National Snow and Ice Data Center
   Data_Center_URL: http://nsidc.org/daac/index.html
   Group: Personnel
      Role: Data Center Contact
      First_Name: NSIDC
      Last_Name: User Services
      Email: nsidc@nsidc.org
      Phone: 1 303 492-6199 
      Fax: 1 303  492-2468 
      Group: Contact_Address
         Address: National Snow and Ice Data Center
         Address: CIRES, 449 UCB
         Address: University of Colorado
         City: Boulder
         Province_or_State: CO
         Postal_Code: 80309-0449
         Country: USA
      End_Group
   End_Group
End_Group
Group: Data_Center
   Data_Center_Name: NSIDC > National Snow and Ice Data Center
   Data_Center_URL: http://nsidc.org
   Group: Personnel
      Role: Data Center Contact
      First_Name: NSIDC
      Last_Name: User Services
      Email: nsidc@nsidc.org
      Phone: 1 303 492-6199 
      Fax: 1 303  492-2468 
      Group: Contact_Address
         Address: National Snow and Ice Data Center
         Address: CIRES, 449 UCB
         Address: University of Colorado
         City: Boulder
         Province_or_State: CO
         Postal_Code: 80309-0449
         Country: USA
      End_Group
   End_Group
End_Group
Group: Distribution
   Distribution_Media: FTP
   Distribution_Format: HDF
End_Group
Group: Summary

   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.

End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW PROJECT HOME PAGE
   End_Group
   URL: http://nsidc.org/data/amsr_validation/soil_moisture/
   Description: NSIDC AMSR-E Validation Data
End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW PROJECT HOME PAGE
   End_Group
   URL: http://nsidc.org/data/amsr_validation/ soil_moisture
   Description: Soil Moisture Experiment (SMEX)
End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW PROJECT HOME PAGE
   End_Group
   URL: http://nsidc.org/data/amsr_validation/soil_moisture
   Description: Soil Moisture Experiment (SMEX)
End_Group
Metadata_Name: CEOS IDN DIF
Metadata_Version: 9.7
DIF_Creation_Date: 2005-08-11
Last_DIF_Revision_Date: 2013-10-10
Group: DIF_Revision_History

   Removed Get External Data and Documentation link and replaced it with Get 
   External Data, cleanup for Search. 

End_Group