Calibration Result of ALOS-2/PALSAR-2 JAXA Standard Products

JAXA/EORC are regularly conducting the calibration and validation of the PALSAR-2 and its standard products using the data over the calibration sites in the world. This page reports evaluation results of the PALSAR-2 standard products and radiometric calibration factors to convert digital number to backscatter value.

Update Information

Mar. 24, 2017:
Oct. 19, 2016:
  • Evaluation results of PALSAR-2 standard products were added.
  • The Calibration Factor (CF) for ScanSAR mode (beam W2) products ordered before Sep. 28, 2016, 7:00 UT has been changed from -83.0 dB to -79.0 dB because an analysis using a lot of data accumulated over Amazonian forests after initial calibration phase revealed that the backscattering coefficient of ScanSAR W2 was low. This issue was corrected in the processing software released on Sep. 28, 2016. We apologize for the incovenience.

Evaluation Results

Calbration factor

Digital number in the PALSAR-2 JAXA standard product is converted to backscattering coefficient (sigma naught, sigma zero) using the following equations:

  • Conversion from digital number (DN) to the backscattering coefficient (sigma-naught) (dB) can be done by the following equations. (1)
  • (for L1.5, L2.1)
  • Conversion from digital number (DN) to the backscattering coefficient (sigma-naught) (dB) can be done by the following equations. (2)
  • (for L1.1)

σ0: Backscattering coefficient (Sigma naught or Sigma zero) [unit: dB]
DN: Digital number (or raw pixel value)
CF1, A: Calibration factor [unit: dB]

Table 1: Values of CF1 and A (Mar. 28, 2017)
Calibration factor Value [dB]
CF1 -83.0
A 32.0
  • Calibration factors (CF1 and A) for the previous version of processing software
    >> Here (PDF file, 126KB)
  • * Version of the PALSAR-2 processing software can be checked in "PALSAR-2 Product Processing Software Release Note" on the AUIG-2 top page after registered user log-in or in the field No.12 of the file descriptor records of each CEOS file.

References

  • M. Shimada, O. Isoguchi, T. Tadono, and K. Isono, "PALSAR Radiometric and Geometric Calibration", IEEE Trans. Geoscience and Remote Sensing, Vol. 47, No. 12, pp.3915-3932, Dec. 2009.
  • M. Shimada, "Model-based Polarimetric SAR Calibration Method Using Forest and Surface-Scattering Targets", IEEE Trans. Geoscience and Remote Sensing, Vol. 49, No. 5, pp.1712-1733, May 2011.