Simulating Organized Convective Storms in Different Climate Zones with Kilometer-Scale Models

Abstract:

Organized convective storms produce the majority of precipitation in the tropics and during summer in the mid-latitudes. Realistically simulating these storms in climate models is essential for representing the global water and energy cycle and for flood and severe convective weather assessments. However, state-of-the-art climate models have substantial biases in simulating convective storms resulting in large uncertainties and errors in assessing climate change impacts on water availability and extreme events. Here we present that kilometer-scale models, which can represent deep convective processes explicitly, show a step improvement in simulating organized convective storms compared to coarser-resolution models. We demonstrate this by synthesizing simulation results from idealized and real case modeling covering tropical, mid-latitude, and arctic environments and by comparing these simulations with high-resolution observational datasets including data from the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facilities. Specifically, we will analyze the grid spacing dependence of simulated organized convective storm properties comparing kilometer-scale models with Large-Eddy simulations and assess the impact of large-scale environmental conditions on model skill in simulating storm characteristics. At the end, we will discuss how these results can inform future model development towards global kilometer-scale climate modeling.