CAREER: Impacts of Convective and Stratiform Processes on Tropical Cyclone Intensity Change

Colorado State University, Fort Collins CO

Investigators

Abstract

This study will investigate the impacts of convective and stratiform processes on tropical cyclone (TC) intensity change through analysis of mesoscale observations, with a focus on aircraft and Doppler radar data. Our ability to skillfully predict changes in TC intensity is still limited, but recent studies have suggested that the radial location of deep convective bursts and stratiform precipitation relative to the radius of maximum wind (RMW) may play an important role in intensification efficiency. Testing these new hypotheses using mesoscale observations is needed to diagnose the most important physical processes responsible for intensity change and improve TC intensity forecasts. Intellectual Merit: Analysis of Doppler radar, dropsonde, satellite, and other observations will be used to examine TC convective and stratiform structures, their thermodynamic and dynamic environment, and their impacts on the TC circulation. Previous theoretical and numerical studies have suggested that convective heating and associated low-level convergence inside the RMW can efficiently intensify the maximum winds. Outside the RMW, mid-level inflow associated with stratiform precipitation can efficiently spin-up the broader circulation through convergence of absolute angular momentum above the frictional boundary layer. The research will use existing research observations at different stages of the TC lifecycle from intensifying and non-intensifying storms to test these hypotheses. A new variational analysis technique called SAMURAI developed by the Principal Investigator will be used to integrate aircraft and radar observations into three-dimensional thermodynamic and kinematic fields for analysis. High-resolution Cartesian and low-wavenumber cylindrical analyses with improved radar thermodynamic retrievals will be conducted and augmented with numerical simulations to improve our understanding of TC intensification. Broader Impacts: This study integrates research and education by developing a new graduate radar meteorology course with a digital, interactive textbook, and incorporating mesoscale TC observations into physical meteorology curricula to train and encourage students to test scientific hypotheses using field observations. The open source SAMURAI analysis software and material from the digital radar meteorology textbook will be available to the atmospheric science community to enhance research and education infrastructure. The University of Hawaii at Manoa represents a demographically and geographically unique state in an EPSCoR jurisdiction, and the Principal Investigator is committed to improving diversity by including women and underrepresented minorities such as Pacific Islanders and Native Hawaiians in the project. Improvements in our understanding of TC intensity change can have a significant positive impact on society. The application of the findings from continued research on hurricanes and typhoons can ultimately help to improve our forecast ability and reduce life and property loss throughout the globe.