Benchmarking Simulated Precipitation in Earth System Models

Abstract:

We describe an effort to advance the objective benchmarking of precipitation as simulated by Earth System Models (ESMs). A diverse suite of precipitation characteristics identified at a recent DOE workshop dedicated to the topic (Pendergrass et al., 2020; https://doi.org/10.1175/BAMS-D-19-0318.1) provides a set of baseline metrics. These include the spatial distribution of mean state precipitation (including snow), seasonal cycle, variability on time scales from diurnal to decadal, intensity and frequency distributions, extremes, and drought. In this presentation we briefly summarize our application of these objective comparisons between models and observations to five generations of atmospheric and coupled models dating back to the early 1990s, with a particular emphasis on the most recent set of models contributed to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). An impetus for this work is to accelerate efforts to improve ESMs by providing a capability to comprehensively evaluate simulated precipitation in ESMs that can assist model developers by providing quantitative targets for demonstrating model improvements and better understanding their models.