Changes are occurring in the Arctic which appear to have begun in the late 1960s and have accelerated in the 1990s. These include tropospheric temperature warming, reductions in sea ice extent, and increased variability in snow cover. In this paper, we will focus our study on the western Arctic and on the temperature changes during the last twenty years. The data sets for the study are NCEP/NCAR reanalysis and TOVS Path-P gridded data.

In terms of the temperature decadal change, both TOVS and NCEP reanalysis show similar patterns, however the magnitude of the change differs. Both analyses show a strong warming during spring time in the lower troposphere with cooling in the stratosphere. In general the magnitude of warm anomalies decrease with height, and change sign above the 300 hpa level. It is clear that the 1990s on the whole were colder aloft, and warmer near the surface, than previous decades. However, each individual year contributes differently to the composite. Our analysis focuses on the connection between the enhanced polar vortex associated with cold anomalies aloft and surface warming at lower levels, when the polar vortex breaks down.