[ESAC Student Seminar] Divya Rea

“On the Termination of Heatwaves”

Terrestrial heatwaves can cause devastating effects both in terms of economic loss and human mortality. They have been extensively studied, primarily from the standpoint of heatwave formation. Studies have identified air subsidence, warm air advection, and diabatic heating as the primary mechanisms for heatwave formation, although the relative importance of each varies on a case-by-case basis. Less work has examined the mechanisms by which heatwaves end. A recent study showed that surface temperatures are limited by the stability of the atmospheric column, which suggests heatwaves will terminate once convection is triggered. Other studies have shown that the likelihood of extreme precipitation increases on the day after a heatwave, again indicating that heatwaves may end with convective precipitation. However, not all heatwaves terminate with precipitation, and some heatwaves persist even after a precipitation event, leaving open the question of how these events terminate.In this study, we examine the processes leading to the termination of heatwaves. We use a Lagrangian mass trajectory approach to calculate forward and backward trajectories of air parcels on the days leading up to and following the end of the heatwave. This facilitates comparison between the processes contributing to the maintenance versus dissipation of the surface temperature anomaly.  We examine the atmospheric stability and the convective initiation to test the hypothesis that convection terminates a heatwave. We present results for cases followed and not followed by precipitation, discussing the mechanisms for heatwave termination in each.

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