Understanding the transportation process of tropospheric air entering the stratosphere from direct vertical air motion measurements over Gadanki and Kototabang

Abstract

Long-term measurements of vertical air velocity (w) obtained with VHF wind profilers are utilized to study mean w features as a function of season at two key geographical locations. It is observed that the magnitude of w is always larger than the error/bias contributed by various contaminators. The seasonal mean w profiles at Gadanki and Kototabang show descending (ascending) motion below (above) 8-10 km in most of the seasons. The magnitude of w observed at the above locations is larger than those obtained from radiative budget estimations. The height of wind reversal seems to have a seasonal dependence at Gadanki. Present observations suggest the transportation of air from near surface to the stratosphere is a two-step process: a rapid ascent from the surface to the middle-upper troposphere in convective turrets, and a gentle ascent into the stratosphere. Also, the convection requires to reach an altitude of 10 km, at least at the above locations, and thereafter the prevailing ascent transports the air into the stratosphere. Copyright 2008 by the American Geophysical Union.