Inter-calibration of Ers Ami and Metop Ascat Backscatter Measurements

Scatterometer derived products have become an important input dataset for climate change research. For this reason accurate radiometric calibration of scatterometer is a prime requirement from the scientific community to enable them to establish a long-term consistent scatterometer dataset. The calibration method that we introduce here is a stepwise relative calibration approach using extended area Land-Targets. Intracalibration of a scatterometer mission will account for instrument related drifts, while inter-calibration is performed to identify possible difference of various scatterometer missions. Similarities in instrument design of ERS-2 AMI and MetOp-A ASCAT allow the merging of these datasets, with the proposed stepwise calibration approach, and result in global backscatter observations spanning over 20 years.