Connecting convective storm initiation to orographic gravity waves to in the lee of the Andes Cordillera using high-resolution model simulations

Stephen Nesbitt, University of Illinois at Urbana-Champaign

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Convective storms in Southeastern South America are some of the deepest and most intense manifestations of atmospheric convection on Earth. These storms lead to severe flooding, large hail and tornadoes which have disastrous consequences for human lives and agriculture in the region. The key objective of our work is to identify mechanisms of convection initiation around the Andean foothills and the foothills of nearby Sierras de Cordoba range in Argentina. We are focused on the potential role of orographically generated gravity waves (GWs) and Kelvin-Helmholtz (KH) instability in initiating deep moist convection. Numerically simulating GW and especially KH waves which in the atmosphere are of the order of a couple of kilometers would require very high resolution modeling with grid spacing around 500 meters over a large region of the South American continent. We plan to perform these simulations using the Cloud Model 1 (CM1) and Weather and Research Forecasting model. A petascale computing facility like Blue Waters can accelerate and contribute to the project tremendously through its I/O-efficient computational resources. This work forms part of the international RELAMPAGO project which aims to study high impact weather in South America.