Global modeling of tropical cyclones at convective scales

Department of Hydrology and Atmospheric Sciences
Weekly Colloquium

April 16, 2020
4 pm via Zoom, no in-person meeting
Zoom socializing before talk ~3:30 to 4:00 pm & after talk ~5:00 to 6:00 pm

Chris Davis
NCAR Associate Director & HAS Visiting Instructor Spring 2020

Abstract

In this talk, I will provide an overview of the Model for Prediction Across Scales (MPAS) and recent work to model tropical cyclones. The emphasis is on convective-scale modeling to understand tropical cyclone formation and climatological aspects of modeling TCs at high resolution. To gain insight into the TC formation process, an idealized aquaplanet configuration is run for many weeks to achieve a statistical steady state in a simplified atmosphere. Tropical cyclone formation events are identified and a composite analysis is performed. The analysis supports many aspects of theory and observations of conditions leading to TC formation, including the process of vertical alignment of pre-TC disturbances, the maintenance of a deep column of near-saturation, and the rapid increase of surface latent heat fluxes.

Bio

Chris Davis received his B. S. in physics from the University of Massachusetts, Amherst in 1985, and his Ph. D. in meteorology from MIT in 1990. His thesis advisor at MIT was Prof. Kerry Emanuel, and the thesis entitled "Cyclogenesis Diagnosed with Potential Vorticity". In the fall of 1990, Dr. Davis began post-doctoral study in the Advanced Studies Program at NCAR. In January, 1992, he became a Scientist I with a joint appointment with the Mesoscale Microscale Division and Research Applications Program.

Chris’s work has concentrated on mesoscale and synoptic-scale phenomena such as extratropical cyclones, tropical cyclones, mesoscale convective systems and cold surges and terrain-induced flows. Work on extratropical cyclones has interpreted observed cyclone development in terms of theoretical models using potential vorticity as a diagnostic tool. Work on mesoscale convective systems has focused on mesoscale vortices produced by long-lived systems, and the possible role such vortices might have in causing subsequent heavy rainfall. Davis was co-science coordinator for the recent Bow-echo and MCV Experiment (BAMEX), a major component of which was to obtain unprecedented observations within and near mesoscale convective systems and remnant mesoscale convective vortices (MCVs) to understand their evolution and the subsequent redevelopment of rainfall.

In recent years, Davis has sought new methods of evaluating short-range numerical forecasts that are objective, yet feature-based. He has also contributed to new verification methods for tropical cyclone forecasts.  These forecasts have been generated by the real-time Advanced Hurricane WRF system that represents an NCAR-University at Albany collaboration.  Chris’s other research on tropical cyclones has focused on mechanisms of mesoscale vorticity organization in the early stages of these storms and on influences of disturbances from the extratropics on this organization.  He was a co-organizer of the PREDICT field campaign in 2010 to study hurricane formation in the Atlantic Ocean.

In much of his work, Davis has consistently bridged theoretical and applied research through a combination of numerical simulation and observational analysis. He has published more than 90 refereed scientific articles and is currently an NCAR Senior Scientist.