Allison Wing - The role of radiative-convective feedbacks in tropical cyclone formation in numerical simulations

Event type: 
Seminar
Date: 
8 March 2018
Time: 
2.00 - 3.00pm
Location: 

Climate Change Research Centre, Seminar Room, Mathews Building 4th floor, UNSW, Sydney

Presenter: 
Allison Wing
Department of Earth, Ocean and Atmospheric Science, Florida State University, USA
Host: 
Climate Change Research Centre, UNSW, Australia

Interactions between convection, moisture, clouds, and radiation can cause tropical convection to “self-aggregate" in idealized numerical simulations. Here, we explore the role of these processes in tropical cyclone formation. First, we perform idealized numerical simulations of rotating radiative-convective equilibrium with a cloud-resolving model, in which, rather than using a weak vortex or moist bubble to initialize the circulation, we allow a circulation to form spontaneously in a homogeneous environment. We compare the resulting tropical cyclogenesis to non-rotating self-aggregation. We find that in the initial development of a broad circulation, the feedback processes leading to cyclogenesis are similar to the initial phase of non-rotating aggregation. Sensitivity tests in which the degree of interactive radiation is modified are also performed to determine the extent to which the radiative feedbacks that are essential to non-rotating self-aggregation are important for tropical cyclogenesis. Radiative feedbacks are found to accelerate cyclogenesis but are not strictly necessary for it to occur.

We then explore the tropical cyclogenesis and intensification processes in realistic historical simulations of tropical cyclones with five high-resolution global climate models. We track the formation and evolution of tropical cyclones in the climate model simulations and apply a moist static energy budget analysis both along the individual tracks and composited over many tropical cyclones. We find that the genesis processes, in terms of the contributions to the moist static energy variance budget, are qualitatively similar across all models and to the cloud-resolving model simulations. 

 

Brief Biography: Allison is an Assistant Professor in the Department of Earth, Ocean and Atmospheric Science (EOAS) at Florida State University (FSU). Her focus is in atmospheric science/meteorology. Prior to arriving at FSU, she was a National Science Foundation (NSF) Postdoctoral Research Fellow at Columbia University's Lamont-Doherty Earth Observatory, in the Divison of Ocean and Climate Physics. She completed my Ph.D. in Atmospheric Science in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology (MIT) in 2014, under the advisement of Professor Kerry Emanuel. Prior to her tenure as a graduate student at MIT, she attended Cornell University where she graduated in 2008 with a Bachelor of Science in Atmospheric Science.

Broadly, she studies atmospheric dynamics and climate, with specific interests in tropical convection and tropical cyclones. Her research interests include the organization of tropical convection and how this modulates tropical and global climate and climate sensitivity, the process of tropical cyclone formation, variability of tropical cyclone intensity, and extreme weather and climate. She uses theory, idealized numerical modeling, and analysis of observations and comprehensive climate models to tackle these problems.