Partitioning of recent surface temperature trends in the Arctic

A method is presented to assess the influences of changes in Arctic cloud cover and sea ice concentration on the recent surface temperature trend in the Arctic, allowing for a more robust diagnosis of causes for surface warming or cooling. Seasonal trends in satellite-derived Arctic surface temperature under clear, cloudy, and all-sky conditions are examined for the period from 1982 to present. The satellite-derived trends are evaluated with trends in the European Center for Medium-Range Weather Forecasts (ECMWF) ERA-40 Reanalysis product and surface-based weather station measurements in the Arctic. The all-sky surface temperature trend is divided into multiple parts, which include a linear combination of the surface temperature trends under clear and cloudy conditions, the trend caused by changes in cloud cover combined with the clear/cloudy surface temperature difference, and the trend as a function of sea ice concentration changes. The relative importance of these components is evaluated in the four seasons.