TY - GEN
T1 - A method for cross-comparison of scatterometer data using natural distributed targets
T2 - Remote Sensing of the Ocean and Sea Ice and Large Water Regions 2012 Conference
AU - Elyouncha, Anis
AU - Neyt, Xavier
PY - 2012
Y1 - 2012
N2 - A methodology of cross-comparison of C-band spaceborne scatterometers is developed and applied to ERS-1 and ERS-2 scatterometers data. Assuming the differences between the instruments can be represented by an incidence-angle dependent bias, this paper presents and discusses four methods providing an estimate of that bias and of its standard deviation. These methods use natural distributed targets such as rainforest, ocean and sea ice, and are based on geophysical model functions, namely constant gamma model, CMOD5 and sea ice line model. The backscatter from the natural distributed targets is compared against a simulated backscatter provided by the models. Finally, the deviation of the two datasets from the models are compared to yield a bias between the two scatterometers. The methodology is applied to ERS-1 and ERS-2 data acquired during the tandem mission in 1996. Generally, the bias between the ERS-1 and ERS-2 scatterometers is smaller than 0.2 dB over most incidence angles and the four methods provide relatively consistent results. However, in order to achieve a consistent backscatter data, the scatterometers need to be inter-calibrated. The methodology can be useful to cross-calibrate scatterometers on-board other satellites (e.g. METOP, OceanSat-2, HY2A, etc.) in the view of the Global Climate Observing System guidelines.
AB - A methodology of cross-comparison of C-band spaceborne scatterometers is developed and applied to ERS-1 and ERS-2 scatterometers data. Assuming the differences between the instruments can be represented by an incidence-angle dependent bias, this paper presents and discusses four methods providing an estimate of that bias and of its standard deviation. These methods use natural distributed targets such as rainforest, ocean and sea ice, and are based on geophysical model functions, namely constant gamma model, CMOD5 and sea ice line model. The backscatter from the natural distributed targets is compared against a simulated backscatter provided by the models. Finally, the deviation of the two datasets from the models are compared to yield a bias between the two scatterometers. The methodology is applied to ERS-1 and ERS-2 data acquired during the tandem mission in 1996. Generally, the bias between the ERS-1 and ERS-2 scatterometers is smaller than 0.2 dB over most incidence angles and the four methods provide relatively consistent results. However, in order to achieve a consistent backscatter data, the scatterometers need to be inter-calibrated. The methodology can be useful to cross-calibrate scatterometers on-board other satellites (e.g. METOP, OceanSat-2, HY2A, etc.) in the view of the Global Climate Observing System guidelines.
KW - ERS-1
KW - ERS-2
KW - Ocean calibration
KW - Scatterometer calibration
UR - http://www.scopus.com/inward/record.url?scp=84887118274&partnerID=8YFLogxK
U2 - 10.1117/12.975218
DO - 10.1117/12.975218
M3 - Conference contribution
AN - SCOPUS:84887118274
SN - 9780819492722
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2012
Y2 - 26 September 2012 through 27 September 2012
ER -