AGS-PRF: The Large Scale Impact of Wind Shear on Convection

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Intellectual merit:At the local scale, it is well known that wind shear influences convection by modulating convective mode and strength. However, how wind shear affects convection at the scales required for climate simulations is unknown. As a result, Global Climate Model (GCM) convective parameterizations do not consider wind shear. This simplification results in errors of unknown size and increased uncertainties for the GCM's estimate of the Earth's hydrologic and radiation budgets, harming future predictions of climate. To help answer this problem, this research will test the following hypothesis: In an equivalent thermodynamic environment, convection will be enhanced in the presence of wind shear at the resolution of a GCM.This hypothesis will be investigated by using a large number of convection resolving model runs. These Weather Research and Forecasting (WRF) simulations will be provided by collaborators at three institutions: National Center for Atmospheric Research, National Severe Storms Laboratory, and National Centers for Environmental Prediction. Convective statistics will be derived from these simulations at the resolution of GCMs to understand how convective properties vary with wind shear in similar thermodynamic environments.Broader impacts:This research will help fill the knowledge gaps that exist between the severe convection and climate modeling communities, and will improve the understanding of the Earth climate system and knowledge of current uncertainties within GCMs. The research results will aid future parameterization development for GCMs by determining whether wind shear and its effects on convection need to be included into future convective parameterizations or may be safely neglected. If this work supports the proposed hypothesis, the statistics derived from this study will serve as a starting place for parameterization developers. Regardless of whether the hypothesis is supported or rejected, policymakers and society will benefit from the increased understanding of the Earth's climate system.Results from this work will be disseminated to both the climate and severe storm communities. This will be accomplished by making results available on a public webpage, presenting results at relevant professional conferences, and publishing the results in refereed journals. There will be additional opportunities to present results at the collaborating institutions, which have provided model simulations for this work.