The Climate Program Office supported a new study published in Earth’s Future that advances efforts to improve projections of how extreme rainfall will increase as global temperatures rise. Extreme rainfall events have significant environmental and societal impacts such as floods or water shortages. The general circulation models scientists use to predict extreme rainfall trends typically have low spatial resolution, representing large areas with just one data point and often missing critical details about precipitation patterns. In the new study, researchers explored whether higher-resolution models could more accurately simulate large storms across the western United States. They found that higher resolution models did not consistently improve accuracy, highlighting the need for a balanced approach that considers both resolution and model intricacies.
The researchers compared historical simulations from high- and low-resolution models against observed precipitation data from thousands of weather stations and several detailed data maps of rainfall patterns. They found that while low-resolution models consistently underestimated the dominance of large storms, higher-resolution models did not consistently improve accuracy. Some high-resolution models showed significant improvements, reducing biases by up to 62 percent, while others showed little change or even amplified errors. This inconsistency suggests that factors beyond just spatial resolution, such as the overall model design and how it simulates precipitation processes, are crucial for accurate predictions. These findings offer valuable insights for future climate modeling and better preparation for extreme weather events in regions with complex landscapes.
Two authors pursued this work with the support of grants from NOAA’s Climate Program Office (CPO). Ben Livneh of the University of Colorado, Boulder received support from the Modeling, Analysis, Predictions, and Projections (MAPP) program and National Integrated Drought Information System (NIDIS) through grants aimed at improving drought and hydrologic predictions. He also leads the Western Water Assessment team with a grant from the Climate Adaptation Partnerships (CAP) program. Angeline Pendergrass of Cornell University received support from the Climate Observations and Monitoring (COM) program through an initiative to develop precipitation datasets and analyses. This study builds on a growing body of cross-CPO-funded research to address important water security and climate issues in the western US and better prepare for future challenges.
For more information, contact Clara Deck.
Image credit: Pixabay