The present study examines the process of how tropospheric air enters thestratosphere, particularly in association with tropical mesoscale convectivesystems (TMCS) which are considered to be one of the causative mechanismsfor the observation of extremely low tropopause temperature over thetropics. The association between the phenomena of convection and theobservation of extreme low tropopause temperature events is, therefore,examined over the Asian monsoon region using data from multiple platforms.Satellite observations show that the area of low outgoing long waveradiation (OLR), which is a proxy for the enhanced convection, is embeddedwith high altitude clouds top temperatures (≤193 K). A detailedanalysis of OLR and 100 hPa temperature shows that both are modulated bywestward propagating Rossby waves with a period of ~15 days,indicating a close linkage between them. The process by which thetropospheric air enters the stratosphere may, in turn, be determined by howthe areas of convection and low tropopause temperature (LTT) i.e. ≤191 Kare spatially located. In this context, the relative spatialdistribution of low OLR and LTT areas is examined. Though, the locations oflow OLR and LTT are noticed in the same broad area, the two do not alwaysoverlap, except for partial overlap in some cases. When there are multiplelow OLR areas, the LTT area generally appears in between the low OLR areas.Implications of these observations are also discussed. The present analysisalso shows that the horizontal mean winds have a role in the spatialdistribution of low OLR and LTT.
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