Jet Propulsion LaboratoryCalifornia Institute of Technology

The NASA/JPL Airborne Synthetic The NASA/JPL Airborne Synthetic Aperture Radar System (AIRSAR)Aperture Radar System (AIRSAR)

Yunling Lou

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

Jet Propulsion LaboratoryCalifornia Institute of TechnologyAIRSAR System CharacteristicsAIRSAR System Characteristics

Simultaneous three-frequency and quad-polarization system P-band (0.68 m), L-band (0.25 m), and C-band (0.057 m) Along-track (ATI) and cross-track (XTI) interferometry capabilities in L &

C-band Bandwidth: 20 MHz, 40 MHz, or 80 MHz (L-band only) Look angle: typically 25o ~ 62o Range swath: ~ 10 km (40 MHz bandwidth) or 15 km (20 MHz

bandwidth), 5 km (80 MHz bandwidth) Noise equivalent sigma0: -45 dB (P/L-band), -30 dB (C-band) Platform: DC-8 at 8 km altitude

Jet Propulsion LaboratoryCalifornia Institute of TechnologyCLPX Data Collection PlanCLPX Data Collection Plan

The objectives of the AIRSAR data collection for CLPX were: Obtain complete coverage of the three MSAs at Rabbit Ears,

North Park, and Fraser in POLSAR mode to validate SWE algorithm

Generate DEM mosaics of the Rabbit Ears, North Park, and Fraser MSAs at 5 m posting

Collect AIRSAR data in different seasons in 2002 Collect AIRSAR data in different snow conditions in March

2003

Jet Propulsion LaboratoryCalifornia Institute of TechnologyCLPX Data Collection SummaryCLPX Data Collection Summary

AIRSAR collected data at all three CLPX sites in February, March, and September of 2002 and in March of 2003

Total number of flight lines: 187 Total raw data volume: about 1.8 TB (935 minutes) Total processed data volume is estimated to be about 280 GB

Jet Propulsion LaboratoryCalifornia Institute of Technology

Example POLSAR Imagery over Example POLSAR Imagery over Fraser, ColoradoFraser, Colorado

P/L/C-band overlay of Fraser270-1, collected on 27 Feb, 2002

Jet Propulsion LaboratoryCalifornia Institute of Technology

Example TOPSAR DEM over Example TOPSAR DEM over Rabbit Ears, ColoradoRabbit Ears, Colorado

C-band DEM of Rabbit Ears 270-1 collected on 13 Feb, 2002

Jet Propulsion LaboratoryCalifornia Institute of TechnologyCLPX Data Processing StatusCLPX Data Processing Status

We have processed about 40 flight lines’ of data to date We are requesting additional processing funding to speed up

the processor throughput We are requesting additional funding to develop software to

generate geo-referenced radar data products in a standard GIS format and to generate mosaics of all three MSA sites.

Jet Propulsion LaboratoryCalifornia Institute of TechnologyAIRSAR Data AccessAIRSAR Data Access

Survey imagery of all the CLPX flight lines are available on AIRSAR’s website

JPEG files of all processed imagery are available on AIRSAR’s website

Request for duplicates of precision data products may be submitted to AIRSAR’s website after the one-year embargo period expires

AIRSAR’s website: http://airsar.jpl.nasa.gov/

Jet Propulsion LaboratoryCalifornia Institute of Technology

SummarySummary

Soil moisture measurement (POLSAR) Surface roughness in sparsely vegetated area (POLSAR) Biomass measurement of forested area (POLSAR) Snow cover and snow wetness classification (frequency

diversity and TOPSAR data) Canopy (type and freezing) classification Topography measurement (TOPSAR) Canopy height measurement (TOPSAR)

AIRSAR data can contribute to the cold land processes experiment in the following area:

Note: TOPSAR data are used to remove terrain dependence in the POLSAR data

Jet Propulsion LaboratoryCalifornia Institute of TechnologyPOLSAR ModePOLSAR Mode

The characteristics of POLSAR mode are: Simultaneous P, L, C-band quad-polarizations (HH, HV, VH, VV) Selectable chirp bandwidth (range resolution): 20 MHz, 40 MHz,

80 MHz (L-band only) Co-registered output imagery in slant range projection (typically

3.3 m x 4.5 m pixel spacing) Output data in compressed Stokes matrix format (10 bytes/pixel) Cross-polarization isolation: better than -20 dB Noise-equivalent sigma0: < -45 dB in P & L-band, < -30 dB in C-

band Absolute calibration: 3 dB for P-band and 2 dB for L & C-band Relative calibration: 0.5 dB between polarization channels and 1.5

dB between frequencies

Jet Propulsion LaboratoryCalifornia Institute of TechnologyPOLSAR Mode (cont.)POLSAR Mode (cont.)

“sigma0c” program to extract arbitrary polarization combination from compressed Stokes matrix file.

Commercial software available to read AIRSAR data format: ENVI.

Polarimetric data are used to estimate soil moisture, surface roughness, forest biomass, and land cover classification.

Radars at longer wavelengths (P-band and L-band) are able to penetrate forest canopy and wet snow.

Jet Propulsion LaboratoryCalifornia Institute of TechnologyTOPSAR ModeTOPSAR Mode

The characteristics of TOPSAR mode are: Simultaneous C-band cross-track interferometry (V-pol), L-band

cross-track interferometry or polarimetry, and P-band polarimetry Selectable chirp bandwidth (range resolution): 20 MHz, 40 MHz Co-registered output imagery in ground range projection Output DEM file in 5 m posting (40 MHz bandwidth) or 10 m

posting (20 MHz bandwidth) RMS height error: 1 - 3 m for C-band and 5 - 10 m for L-band C and L-band DEMs provide information on differential

penetration into tree canopy

Jet Propulsion LaboratoryCalifornia Institute of TechnologyTOPSAR Mode (cont.)TOPSAR Mode (cont.)

Standard output data products include: DEM file in 5 m or 10 m posting VV magnitude imagery (calibrated radar backscattering cross-

section) Local incidence angle map Correlation map L-band (if available) and P-band compressed Stokes matrix files All output files are co-registered in ground range projection DEM is used for terrain correction on POLSAR data