Arctic surface temperatures from Metop AVHRR compared to in situ ocean and land data

[摘要] The ice surface temperature (IST) is an important boundary condition for bothatmospheric and ocean and sea ice models and for coupled systems. Anoperational ice surface temperature product using satellite Metop AVHRRinfra-red data was developed for MyOcean. The IST can be mapped in clear skyregions using a split window algorithm specially tuned for sea ice. Clear skyconditions prevail during spring in the Arctic, while persistent cloudcover limits data coverage during summer. The cloud covered regions aredetected using the EUMETSAT cloud mask. The Metop IST compares to 2 mtemperature at the Greenland ice cap Summit within STD error of3.14 °C and to Arctic drifting buoy temperature data within STD errorof 3.69 °C. A case study reveals that the in situ radiometer dataversus satellite IST STD error can be much lower (0.73 °C) and thatthe different in situ measurements complicate the validation. Differences andvariability between Metop IST and in situ data are analysed and discussed. Aninter-comparison of Metop IST, numerical weather prediction temperatures andin situ observation indicates large biases between the different quantities.Because of the scarcity of conventional surface temperature or surface airtemperature data in the Arctic, the satellite IST data with its relativelygood coverage can potentially add valuable information to model analysis forthe Arctic atmosphere.

[学科分类] 海洋学与技术