CWEX

Convective Windsonde Entrainment Experiment

1 July 2025 - 1 August 2026

Lead Scientist: Kathleen Schiro

Observatory: AMF (ARM Mobile Facility 3)

Preliminary results from Windsond radiosonde launches during summer, 2021, at the University of Virginia (Charlottesville, Virginia) suggest that frequent sampling of deep convective events from a single site permits sampling of the surrounding environmental conditions supporting convection as well as sampling within updrafts and downdrafts.

A growing body of evidence suggests that significant entrainment occurs in deep convection, despite very little being understood about the process itself, given how difficult it is to infer characteristics of entrainment from observational platforms. Given the slow ascent and lightweight nature of Windsonds, recent work by the proposal team suggests that Windsonds will occasionally enter deep convective updrafts and downdrafts. With data from a pre-convective sounding hours before (or a Windsond launched simultaneously that remains outside the system), it becomes possible to estimate entrainment rates and infer other characteristics of entrainment (e.g., profiles) within updrafts and downdrafts. This novel application of Windsonds to study a process that is critical to deep convection presents an opportunity to make significant scientific progress.

We aim to gather enough samples from Windsond launches over a single summer season during which Windsonds get entrained into convective updrafts and/or sample the immediate surroundings of convection, to glean insight into the process of entrainment and the role of lower free tropospheric humidity in supporting different types of convective systems at the Third ARM Mobile Facility (AMF3) site in Alabama’s Bankhead National Forest. Windsondes would be launched at or near the main AMF3 instrument site in warm months, ideally coincidentally with an intensive operational period.