In the tropical upper troposphere, clouds and water vapor interact on a range of spatio-temporal scales driven by various atmospheric and coupled ocean-atmosphere circulation patterns including the El Nino-Southern Oscillation, seasonal cycle, Madden-Julian oscillation (MJO) and Kelvin waves. With the advent of EOS satellites, clouds and water vapor in the tropical upper troposphere can be observed as never before. In the proposed research we will combine several EOS datasets to produce a comprehensive view of the interaction of the MJO cloud hierarchy and moisture fields with dynamical variability, focusing on closely related problems. These problems include (i) examination of atmospheric processes responsible for an observed association between SST and cloud microphysical properties in the tropics, (ii) the response of upper tropospheric water vapor to the MJO in the subtropics, (iii) cloud-radiative implications of the 3D response to the MJO, and (iv) moisture-transport implications of the 3D response, including a water vapor dipole in the upper troposphere and systematic variations of congestus cloud population in the middle troposphere. The proposed research will identify the phase relationships between moisture and dynamical variations and will provide quantitative information on the radiative forcing (due to vapor and ice cloud) as organized by these phenomena. This information is necessary for a complete understanding of the role of clouds in climate. Comparison with UARS data will provide a first glimpse of interdecadal variations in the tropical UT/LS and how this region of the atmosphere is responding to global change. Research on hurricane genesis using EOS data products is also highlighted.
