Sea temperature fiducial reference measurements for validating satellite SST data products

The Infrared Sea surface temperature Autonomous Radiometer (ISAR) was developed to provide reference data for the validation of satellite SST_skin temperature data products, particularly the Advanced Along Track Scanning Radiometer (AATSR). Since March 2004 ISAR instruments have been deployed nearly continuously on ferries crossing the English Channel and the Bay of Biscay, between Portsmouth (UK) and Bilbao/Santander (Spain). The resulting twelve years of ISAR data, including an individual uncertainty estimate for each SST record, are calibrated with traceability to national standards (NIST and NPL).They provide a unique independent in situ reference dataset against which to validate satellite derived products. We present results of the AATSR validation and the gap bridging between the AATSR and the Sea and Land Surface Temperature Radiometer (SLSTR). ISAR data were also used to review the performance of the UK MetOffice OSTIA SST analysis before during and after the AATSR to SLSTR data gap. Thus demonstrating the use of ISAR fiducial reference measurements as a common data source which both AATSR and SLSTR are validated against. Validation results for AVHRR, MODIS and SEVRI SST are also reported to show their performance in the AATSR – SLSTR data gap and their potential use in a data gap filling exercise.