The Mid-Latitude Mesosphere’s Response to Sudden Stratospheric Warmings as Determined from Rayleigh Lidar Temperatures

The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. Recently, they were combined with other observations to examine the mid-latitude responses to Sudden Stratospheric Warmings (SSWs) in the polar regions. (The other observational instruments being an ionosonde, a meteor wind radar, a Na lidar, and a satellite.) Extensive Rayleigh lidar observations were made during a dozen SSW events. In order to look for effects of the SSWs, comparisons were made between the temperature profile on individual nights during an SSW event and the climatological temperature profile for that night of the year. An overall disturbance pattern was observed in the mesospheric temperatures during northern hemisphere SSWs. It included coolings (sometimes very significant) in the upper mesosphere and warmings in the lower mesosphere. Examples of the effects in the mesosphere from southern hemisphere SSWs are also given