Multi-sensor perspectives on the convective and radiative properties of the Tropopause Layer over the Tropical Americas
Jasna V. Pittman, USRA, Huntsville, AL; and F. R. Robertson and T. L. Miller
Understanding the mechanisms that set the boundary conditions of air entering the stratosphere is necessary in order to accurately predict the response of the atmosphere to thermal and chemical changes resulting from climate forcing by infrared active species. In this paper, the convective and radiative processes that control transport in the Tropical Tropopause Layer (TTL), the dominant source of air to the stratosphere, are explored. This paper focuses on the region of the Tropical Americas. This region is chosen for the following reasons: (i) it becomes the second most dominant source of air to the TTL, (ii) it exhibits the largest seasonal increase in percent contribution to stratospheric moisture, (iii) it has the warmest tropical tropopause temperatures, and (iv) it can be influenced by midlatitude and subtropical air masses that are transported equatorward by the upper-level circulation associated with the North American Monsoon. In this paper, space-borne and aircraft-borne measurements are used to examine the vertical distribution of temperature, chemical tracers such as water vapor and ozone, two key constituents that have a dominant effect on the radiative balance of the TTL, and the vertical extent and frequency of convective cells that penetrate the TTL. Satellite data are obtained from the Tropical Rainfall Measurement Mission, the Microwave Limb Sounder aboard the UARS and Aura satellites, the AIRS instrument aboard the Aqua satellite, and GPS receivers aboard the CHAMP satellite. Aircraft data are obtained from instruments that fly aboard NASA's WB-57. In addition to using remote and in-situ measurements, trajectory and radiative transfer calculations are performed in order to identify the origin of air masses and the heat balance of the TTL over the longitudes of interest.
Poster Session 3, Environmental Applications
Wednesday, 1 February 2006, 2:30 PM-2:30 PM, Exhibit Hall A2
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