Collaborative Research: Convective Upscale Growth Processes during RELAMPAGO

Colorado State University, Fort Collins CO

Investigators

Abstract

Storms spanning hundreds of kilometers and lasting for hours into days have an important role in our global water cycle. In subtropical South America east of the Andes, 95% of rainfall during the warmer months are attributed to these large systems, which also can produce flash floods, devastating hail, and frequent lightning. In late 2018 into early 2019, an international team of scientists conducted the Remote sensing of Electrification, Lightning, and Mesoscale/microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign near the Sierras de Cordoba mountains in central Argentina to study these frequent, impactful storms with observations at higher temporal and spatial resolution. Initial results from this campaign have provided valuable insight into conditions supporting the initiation and rapid growth of these storms, yet many questions remain regarding the specific evolution of the storms and the hazardous weather they produce. Therefore, this project builds off the initial RELAMPAGO findings to further understand the processes occurring within storms as they rapidly grow large and how the conditions that support these processes compare with those in other mountainous regions of the world that experience similarly hazardous conditions. This research also permits continued education and outreach opportunities through training of graduate students, international collaborations, and representation through a diverse team. Prediction of mesoscale convective systems (MCSs) is challenged in part by limitations in understanding and representation of the convective lifecycle. A region in central Argentina near the Sierras de Córdoba mountain range is a global hotspot for deep and intense severe convection that also grows rapidly upscale to MCSs producing flooding, hail, and frequent lightning. This area was a focal point for RELAMPAGO field campaign, for which initial results from the datasets supported previous satellite-based inferences of convective lifecycle and contributed new findings related to the role of mid-level vertical wind shear, the South American Low-Level Jet, and terrain interactions in the upscale growth process. This research builds off those results to address the following overarching science questions: 1) How do microphysics and kinematics within convective systems evolve as they grow upscale? 2) Which synoptic and mesoscale factors support rapid upscale growth of convection and how does terrain modify those factors? A combination of RELAMPAGO data analysis, high-resolution model simulations, and reanalysis data provides the means to address these questions and gain a better understanding of convective upscale growth to MCSs, the environmental controls on these upscale growth processes, and the production of high lightning flash rates and hail during upscale growth. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.