Structure of tropopause polar vortices represented from the atmospheric profiles of satellite observations

Abstract

Tropopause polar vortices (TPVs) are sub-synoptic tropopause disturbances commonly found poleward of the polar jet stream. Their roles in cyclogenesis and linkages to mid-latitude weather make them relevant to the improvement of numerical weather prediction. Previous TPV studies have been mostly model-based, whereas observational studies are limited. The purpose of this study is to characterize the three-dimensional composite temperature and water vapor structure of TPVs using retrieved atmospheric quantities from the Atmospheric Infrared Sounder (AIRS) and to verify these results with the TPV structure documented in previous model-based and observational studies. The composite structure of AIRS-observed TPVs averaged over a one-year period exhibits a cold (warm) temperature anomaly and a positive (negative) relative humidity anomaly in the troposphere (lower stratosphere). TPV composites also reveal dry mixing ratio anomalies throughout the troposphere and lower stratosphere, and that the percent decrease in mixing ratio is largest at the tropopause at the vortex center. This study thus confirms TPV structure previously characterized in models and surface-based observations. This illustrates the potential usefulness that hyperspectral atmospheric profilers on polar-orbiting satellites have in representing TPVs over the high latitudes where observational data is scarce.