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The evaluation of fronts and frontal precipitation in high-resolution climate models

Presentation Date
Wednesday, December 14, 2022 at 9:00am - Wednesday, December 14, 2022 at 12:30pm
McCormick Place - Poster Hall, Hall - A



Extratropical cyclones and associated fronts are core to day-to-day midlatitude weather variability. A method to objectively identify and track frontal objects is developed using reanalysis data. Frontal objects are co-located with precipitation and extreme precipitation (defined as 95th percentile precipitation) objects to determine how much precipitation and extreme precipitation can be attributed to fronts using ECMWF reanalysis 5 (ERA5) data and Integrated Multi-satellitE Retrievals for GPM (IMERG) precipitation data. Sensitivity analysis techniques are performed to determined how changes in input parameters for identifying and tracking fronts and frontal precipitation influences output metrics. From this sensitivity analysis, input parameters are optimized to ERA5 and IMERG data. The objective tracking methods are applied to the Energy Exascale Earth System Model (E3SM) under a variety of prototype high resolution configurations. The model configurations—high resolution (HR), with a horizontal resolution of ~25 km, and multi-scale modeling framework (MMF), which uses embedded cloud-resolving models—have been shown to improve precipitation frequency and intensity biases in some cases as compared to conventional low resolution (LR) configurations. Particularly, both E3SMv1-MMF and E3SMv1-HR demonstrate better general extratropical cyclone precipitation across the United States. To understand the role of fronts in this improvement of extratropical cyclone precipitation, fronts and frontal precipitation will be tracked globally in all 3 simulations to determine how well the model captures frontal precipitation compared to observations, and evaluate improvements in both high resolution model configurations relative to observations compared to E3SMv1-LR. This work will inform which configuration of E3SM is best suited for simulations that explore changes in frontal precipitation in future climate.

Funding Program Area(s)