SEASONAL-VARIATIONS OF WATER-VAPOR IN THE TROPICAL LOWER STRATOSPHERE

Measurements of stratospheric water vapor by the Microwave Limb Sounde r aboard the Upper Atmosphere Research Satellite show that in the trop ical lower stratosphere, low-frequency variations are closely related to the annual cycle in tropical tropopause temperatures. Tropical stra tospheric air appears to retain information about the tropopause condi tions it encountered for over a year as it rises through the stratosph ere. We use a two-dimensional Lagrangian model to relate MLS measureme nts to the temperature that tropical air parcels encountered when cros sing the 100 hPa surface.