Assessment of summer precipitation events through different convection-permitting WRF simulations in the Central Andes (30-35°S)

Modeling precipitation in complex terrains remains one of the most challenging issues in mesoscale meteorology. Summer precipitation events in the western central Andes (30-35°S) have not received much attention due to the low contribution to annual precipitation (< 10%); nevertheless, in the eastern Andes, these kinds of events are the primary source of rainfall. The precipitation mechanisms are also quite different on both sides of the Andes due to the moisture source, transport, and dynamics. In this study, we analyze different model configurations of the Advanced Weather Research and Forecasting model (WRF) using a convection-permitting scale (~4km) in the representation of two summer precipitation events associated with i) Cutoff Low and ii) Atmospheric River. We explore the WRF configuration sensitivities, including land surface and planetary boundary layer schemes, as well as vertical discretization in representing these events. In addition, we also include the High-Resolution simulations being carried out in South America by the NCAR and South American Affinity Group community for further assessments and comparisons.

Model evaluation and validation are carried out using surface observations (precipitation and temperature) at hourly and daily scales and the Integrated Multi-satellitE Retrievals for GPM (IMERG) to analyze the spatial patterns. In addition, sounding data are used to explore the representation of Boundary Layer height, instability, and vertical structure of the simulated events. Our results have the potential to improve the WRF configuration sensitivities in representing summer precipitation events in the Andes, aiming to contribute to mountain hydrometeorology research, weather forecasting, and climate change studies.