Multi-Scale Observational Analyses within the "Marsupial Pouch" of Pre-Depression Tropical Disturbances

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The prediction and understanding of tropical cyclogenesis remains one of the most challenging problems in the atmospheric sciences. A multitude of tropical disturbances emerge from the West African coast every year near the Cape Verde islands, but only a few of these develop into tropical depressions, storms, or hurricanes. To further understanding of these potentially high impact events, the PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT) field experiment will deploy the NSF G-V aircraft in the Atlantic basin to explore multi-scale interactions that may promote or hinder the development of a tropical depression vortex. The PREDICT team will coordinate research with concurrent NASA and NOAA projects. Research will focus on the synthesis, analysis and interpretation of the observational datasets obtained by the G-V, NOAA and NASA aircraft. Tropospheric dropwindsonde observations, radar data, and in situ data at multiple flight levels will offer a unique dataset for examining the development and growth of tropical cyclone precursors. By combining data from multiple instruments and platforms, mesoscale and synoptic scale composites of vorticity, divergence, moisture, and potential vorticity will be used to diagnose the structure and evolution of disturbances in the Atlantic. Multiscale analyses of the datasets will be accomplished through the use of objective and variational techniques that allow for quantitative study of the structures and budgets of key quantities related to the primary hypotheses. Multidimensional composites of temperature and humidity have so far been limited or non-existent in most pre-depression disturbances, but the G-V aircraft provides an ideal platform for obtaining the measurements needed to construct these syntheses. The high-resolution vertical structure obtained from dropsondes and the microwave temperature profiler complements the significant horizontal coverage of in situ data from the Gulfstream aircraft, allowing for unique compositing opportunities. The cloud and precipitation radar data from the G-V and NOAA aircraft will provide unprecedented opportunities for investigations into the wave-to-vortex transformation process. The research team will also compare and contrast these results with data obtained from other hurricanes in different locales. Intellectual Merit: Recent theoretical, logistical, and technological advancements allow for testing new dynamical/thermodynamical hypotheses on the role of tropical waves, mesoscale and convective processes in tropical cyclone development. Broader Impacts: The research will be in close collaboration with other principal investigators and students in order to obtain the maximum synergy between the observational analyses, theoretical understanding, and numerical modeling and prediction. Successful completion of this research could result in improved forecasts of tropical cyclones.