Characteristics of African Sahel Precipitation in global storm-resolving Climate Models

The simulation of precipitation in the African Sahel region is challenging for current global climate models. These models conventionally work with grids with horizontal resolution larger than 100 km and therefore must use parametrization schemes to simulate deep convection. The nextGEMS project, on the other hand, performs global simulations with two new climate models (adapted versions of ICON and IFS) with fine resolutions of a few kilometers. At such high resolution, deep convection is resolved, which allows for a much more realistic representation of precipitation. This is particularly promising for simulating convection in the African Sahel, where most precipitation originates from mesoscale convective systems resolved at these simulation scales. 

We present a preliminary analysis of the cycle two nextGEMS simulations focusing on Sahel precipitation and the West African monsoon. We show that some characteristics of precipitation, such as low autocorrelation with one day lag, are much closer to measurements compared to conventional climate models. We also discuss some of the problems that still persist in the simulations and compare the two models depending on different features of Sahel precipitation.