[ESAC Seminar] Divya Rea

“On the Termination of Heatwaves”

Heatwaves, prolonged periods of above average surface temperatures, are potentially devastating extreme weather events with impacts on life, infrastructure, and ecosystems. Studies have shown that in a warming world, heatwaves are projected to become more frequent, more persistent, and more intense. Many studies have focused on the mechanisms of heatwave formation, finding that heatwaves typically form due to a combination air subsidence, warm air advection, and diabatic effects, although the relative importance of each can vary from case to case.

Fewer studies have considered the mechanisms by which heatwaves end. It has been shown that surface temperatures are limited by the stability of the atmosphere above it, which suggests that heatwaves will terminate once the atmospheric column becomes unstable and convection is triggered. It has also been shown that heatwaves may prime the atmosphere for extreme precipitation, making convection (and convective precipitation) more likely at the end of the heatwave. However, sometimes heatwaves end without precipitation, and sometimes precipitation doesn’t end a heatwave.

In this study, we consider the question of how heatwaves end. We present two case studies of record-breaking heatwaves, one of which ended with precipitation and the other without. Using a combination of Lagrangian and Eulerian approaches, we identify the sources and sinks of moist static energy to these two heatwaves, and determine the dominant processes responsible for the loss of MSE and decrease in surface temperatures for each case.

ESAC Student Seminar Series —

A forum for students and postdocs to share recent research, hone presentation skills, and build community among peers, sponsored by the EAPS Student Advisory Committee. Open to current EAPS graduate and undergraduate students and postdocs. Typically hosted on Thursdays during the semester, including pizza lunch.

Contact: esac.officers@gmail.com