Climate variability for Arctic Alaska

Barrow is the only long-term meteorological station in US Arctic which continues to operate, with a record going back to 1921. Applying the best linear fit to the temperature series, a temperature increase is being observed similar to the one observed for the mean of the northern hemisphere. However, the temperature record is non-linear. A period of warm temperatures were witnessed from 1921-1950, the period from 1950-1975 saw temperatures that were cool, while since 1975 a warming has occurred. This temperature increase was accompanied by a decrease in precipitation, which was widespread including the North Slope of Alaska, Northern Canada and the Arctic Ocean. Intuitively one would assume a precipitation increase with the observed surface temperature increase. Using surface data, we were unable to explain the opposing trends, however, rawinsonde analyses showed that the warming was limited to the lowest levels of the atmosphere, with cooling in the upper troposphere and stratosphere. This was seen especially in winter. Heights at which most moisture was advected did not show this warming.

Further, the Pacific Decadal Oscillation (PDO) supported the decreasing precipitation amount. The cyclic nature of the PDO would indicate an increase in precipitation over the next decade.