Observational evidence of moistening the lowermost stratosphere via isentropic mixing across the subtropical jet

Abstract

pIsentropic mixing across and above the subtropical jet is a significant mechanism for stratosphere-troposphere exchange. In this work, we show new observational evidence on the role of this process in moistening the lowermost stratosphere. The new measurement, obtained from the Spatial Heterodyne Observations of Water (SHOW) instrument during a demonstration flight on the NASA's ER-2 high-altitude research aircraft, captured an event of poleward water vapour transport, including a fine-scale (vertically span classCombining double low line"inline-formula"i