Assimilation of Wind Data Obtained during NASA CPEX (2017) Field Phase to Understand Organization of Convection over Gulf of Mexico

Most tropical disturbances, such as tropical cyclones emerge from organization of convection over their life cycles of intensification. A major, unsolved, scientific problem is that of understanding the factors responsible for either the organization of convection or in many cases the lack of it. Towards the fulfillment of this purpose two events have been chosen to study; a) pre-cyclone condition:- 17th-19th June convective system and b)Tropical cyclone generation:- development of tropical cyclone Cindy over the Gulf of Mexico. Among these two cases mentioned, first one which is just a convective system sustained for ~30hr period and second case transformed into a named tropical cyclone (Cindy) with a life time ~72hrs. For these two cases dropsondes data and wind lidar data were collected. High resolution WRF model has been used to simulate the systems. As the first step of scientific analysis the issue of organization of convection was addressed through an energetics view point. Here, we quantitatively analyze the generation of eddy available potential energy and its transformation to kinetic energy, which occurs on the same scales as that of the organization of convection. These are called the in-scale energetics. The next step involves assimilation of wind observations obtained during the period mentioned above. The whole assimilation process is divided into two parts:-

i)

ii)

Control integration captures existing vortex in case of Cindy. It is anticipated that assimilation of the winds from the CPEX 2017 field program would further improve the results. For validation purpose, the results of the model are verified with satellite imageries and APR2 radar reflectivity data. Perturbation in initial condition would cause the vortex to disrupt and there will be no tropical storm scenario over GoM. Assimilation of wind data will give results where development of tropical disturbance would be evident again. Assimilation of wind data would reflect that ‘how well’ and ‘what extent’ observations are capable of capturing the intricate and necessary details for the development of tropical disturbance.