Synoptic scale study of the Arctic polar vortex's influence on the middle atmosphere, 1, Observations

Abstract

We present nightly Rayleigh lidar temperature measurements of the high‐latitude middle atmosphere taken at three Arctic sites over similar time periods in midwinter. The four reported case studies depict changes in the thermal structure of the stratosphere and lower mesosphere over a period of days to weeks that can be attributed to movement and interaction of the polar vortex, the Aleutian High, and planetary waves as evidenced from the National Center for Environmental Prediction tropospheric and stratospheric analyses. In cases where substantial (i.e., large horizontal scale) movement of the vortex is observed, it is noted that regional middle atmospheric Arctic temperatures can change by tens of degrees. In other cases, we show that even very subtle (i.e., small horizontal scale) movement of the vortex system over similar timescales can result in notable temperature changes in the regional middle atmosphere. It appears that the observed events are dependant on the location, strength, and structure of the polar vortex and Aleutian High. All of these synoptic scale measurements indicate a change in the local dynamical structure of the middle atmosphere and are discussed in regards to this issue.