Calibrating SeaWinds and QuikSCAT scatterometers using natural land targets

• Main Authors: Lukas B. Kunz, Student Member, David G. Long, Senior Member
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.391.7269; http://www.mers.byu.edu/long/papers/GRSL2005AprKunz.pdf

SeaWinds-on-ADEOS-2 (SeaWinds) scatterometers measure the normalized radar backscatter ( ) of the earth’s surface. These identical radar sensors are on different spaceborne platforms in similar orbits. QuikSCAT and SeaWinds data are used to infer near-surface wind vectors, polar sea-ice extent, polar-ice melt events, etc. In order to verify the relative calibration of these sensors, a simple cross calibration based on land backscatter measurements is performed. A first-order polynomial model is used to remove the incidence angle dependence of for selected regions of the Amazon rainforest and the Sahara Desert. It is shown that the two sensors are well-calibrated to each other and require no bias corrections. Additionally, evidence of a diurnal cycle in the Amazon rainforest backscatter is given. Index Terms—Amazon forest, calibration, QuikSCAT, radar cross section, SeaWinds.