Recent observations of a spring-summer surface warming over the Arctic Ocean

For the Arctic Ocean, a 1961-1990 trend analysis of the 2-m, 6-hourly air temperatures from the Russian North Pole (NP) drifting ice stations shows a significant warming in May and June, or seasonally in summer. In this analysis, if we choose temperatures from only those stations which report at least 95% of the time, and define an anomaly field by removal of a mean temperature field, then for both the temperature and anomaly fields, we obtain statistically significant May and June warmings of respectively 0.8 and 0.4 degrees C/decade, and a summer seasonal warming of 0.2 degrees C/decade. For the other seasons, although our trends are not statistically significant, they match the trends derived for the same period from the Arctic land stations.