Accuracy of sea ice temperature derived from the advanced very high resolution radiometer

摘要: The accuracy of Arctic sea ice surface temperatures Ts derived from advanced very high resolution radiometer (AVHRR) thermal channels is evaluated in the cold seasons by comparing them with air Tair drifting buoys and stations. We use three different estimates satellite temperatures, a direct estimate AVHRR channel 4 only correction for snow emissivity but not atmosphere, single-channel regression Tair, Key Haefliger's (1992) polar multichannel algorithm. find no measurable bias any these few differences their statistics. similar performance all methods indicates that an atmospheric water vapor important dry winter atmosphere central Arctic, given other sources error remain both comparison data. errors are reduced scan angle. A record station data shows temperature to be 1.4°C wanner than temperature. “Correcting” skin subtracting this amount implies biased warm respect about amount. case study low-flying aircraft suggests crystal precipitation can cause several degrees warmer radiometric measurements taken close surface, presumably below layer. An analysis which assumed exist measurements, just gives standard deviation 0.9°C, half 1.7°C estimated assigning variation between Ts.