Interannual variability of Arctic summer ice surface characteristics using satellite observations

Surface air temperatures recorded by stations in the Arctic region have been observed to be increasing at 0.07 K/decade while at the same time, the sea ice cover has declined by about 6% during the last 20 years. In order to gain insights into this phenomenon, albedo and surface temperature data from AVHRR have been processed and analyzed in conjunction with co-registered ice cover data from passive microwave observations. This study puts emphasis on the summer period because it is during this time when the impact of changes in surface temperature on the character of the ice cover is most critical. The results of the authors' analysis show that the spatial and interannual variability in surface temperature in the Arctic during the last 18 years has been large and the impact is reflected on the albedo and ice data. There is also good coherence in the different variables studied, including ice concentration and brightness temperatures. Lengths of summer melt periods are also shown to be vary considerably and can be as short as 7 weeks or as long as 19 weeks. Abnormally warm temperatures are usually correlated with abnormally low albedos but not always.