Observed Connections Between Arctic Stratosphere Temperature Fluctuations, Amounts of air Below the Threshold for PSC Formation, and Stratospheric Warmings.

The temperatures observed at the Arctic stratosphere are described for the years 2001-2005 and compared to the weather analyses from the ECMWF. The temperature profiles were captured with GPS occultations. We show that months having the most air mass with temperatures reaching below the threshold for Polar Stratospheric Cloud (PSC) formation (STS, NAT, ice) are correlated with increased presence of vertical temperature fluctuations, possibly associated with wave activity. These periods of increased wave activity tend to be observed simultaneously with wintertime stratospheric warmings. We show examples from the Winters of the years 2001/02 through 2004/2005 which covers a variety of stratospheric conditions. In December 2004-January 2005 stratospheric temperatures were colder than the previous few years, and warming occurred slowly. In the prior years sudden warmings occured typically in December, which did not occur in 2004/2005. We discuss the main differences between these winters and the impact in quantities of air mass conducive to PSCS, amounts of temperature fluctuations, and the evolution of the stratospheric warmings.