Overview of the LASSO 2017 Large-Eddy Simulations of Continental Shallow Convection at the Southern Great Plains

Continental shallow convection is difficult for weather and climate models to parameterize accurately. The U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Research Facility has begun producing routine large-eddy simulations (LES) of this meteorological regime to supplement ARM’s large suite of observations with one of the primary goals being to improve process understanding and parameterization of shallow convection. This new datastream, called the LES ARM Symbiotic Simulation and Observation (LASSO) workflow, has transitioned from its pilot phase to ongoing, routine operations (https://www.arm.gov/capabilities/modeling/lasso). The set of data bundles for the 2017 shallow convection season are the first to be produced after this transition and reflect a stable datastream that will continue to be produced going forward. This first, full implementation of LASSO focuses on simulating continental shallow convection at ARM’s Southern Great Plains observatory in Oklahoma, which predominately occurs in spring and summer. Thirty-two days have been selected for the period April–October 2017, and an ensemble of forcing data sets are used to drive the LES for each of these days. The forcing ensemble, built from multiple input sources combined with multiple horizontal spatial scales, increases the likelihood of accurately representing the observed environment on each day. A statistical analysis of the simulations and how they compare with observations will be presented.