Studies in the Climate Dynamics of Moist Processes

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This project examines fundamental properties of tropical convective rainfall and its complex relationship to large-scale atmospheric conditions. The work builds on previous work by the same group which found that several important properties of tropical precipitation including frequency of occurrence, variance, and intensity, show simple behavior when treated as functions of bulk atmospheric water vapor content divided by a critical water vapor value related to temperature-dependent saturation specific humidity. The work is divided into four topics: 1) Observational constraints on representations of moisture, convection, and their interactions; 2) distribution tails associated with transport processes and their implications, particularly for extreme precipitation events; 3) Issues in precipitation simulation, moist teleconnections and convective margins, and 4) Methods for parameter sensitivity estimation/optimization with a focus on precipitation processes in regional climate issues.The behavior of convective precipitation in the tropics is of immense practical importance, as the source of moisture for the large portion of the world's population residing in the tropics. Yet despite its importance the nature of tropical convection remains mysterious, as convective rainfall is governed by complex interactions between large-scale atmospheric conditions and the properties of small-scale convective clouds. Research conducted here seeks to improve understanding of tropical convection and its representation in weather and climate models, and such improvements have great potential benefit for decision makers confronted with the impacts of tropical climate variability (including El Nino events) and tropical climate change.