The MODIS ice surface temperature product as an indicator of sea ice minimum over the Arctic Ocean

Abstract

This study examines the relationship between sea ice extent and ice surface temperature (IST) between 2000 and 2013 using daily IST products from the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The empirical prediction of September sea ice extent using its trend and two climate variables-IST and wind vorticity-exhibits a statistically significant relationship (R=0.97) with a time lag, where IST maximum in summer (June-July) corresponds to the sea ice extent minimum in September. This suggests that IST may serve as an indicator of the basin-wide heat energy accumulated in the Arctic by solar radiation and large-scale atmospheric heat transport from lower latitudes. The process of inducing higher IST is related to the change of atmospheric circulation over the Arctic. Averaged IST and 850hPa relative vorticity of the polar region show a significant negative correlation (-0.57) in boreal summer (June-August), suggesting a weakening of the polar vortex in the case of warmer-than-normal IST conditions. Weakening of the polar vortex is accompanied by above-normal surface pressure. Minimum sea ice extent in September was successfully predicted by both multiple linear regression and machine learning support vector regression using preceding summer IST and wind vorticity along with the trend of sea ice extent (R2~0.95, cross validation RMSE of 3-4×105km2, and relative cross validation RMSE of 5-8%).