Climate trends and variability in Alaska since 1950

The northern hemisphere has experienced a general warming trend in recent decades that is most pronounced at high latitudes. For Alaska, the mean annual temperature has increased approximately 1.4°C for the most recent climate normal (1971-2000). However, it is important to note that the increase is non-linear and exhibits seasonal and spatial variability. In this investigation, climate records for the 21 first-order observing stations in Alaska were examined for the period 1950 to 2001. Spatial coverage is such that the three climate regimes in the state (arctic, continental, and maritime) are represented. Seasonal temperature trends show that the greatest warming has occurred in winter and spring, while many locations show a temperature decrease in autumn. For most locations, the period of time with snow on the ground exhibits a similar trend with an earlier onset followed by an earlier melt, with no significant trend in snow season length. The frequency of extreme cold temperature events in winter for the interior region has decreased significantly since 1950. Additionally, a precipitation shift is evident for coastal locations along the southeastern panhandle in which an increase in total precipitation is coincident with a marked decrease in solid precipitation.