The Hydrologic Cycle and Atmospheric Rivers in CESM2 Simulations of the Last Glacial Maximum

• Published in: Geophysical Research Letters
• Main Authors: J. M. Lora, C. B. Skinner, W. D. Rush, S. H. Baek
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: atmospheric rivers; hydroclimate; Last Glacial Maximum; paleoclimate; Geophysics. Cosmic physics; QC801-809; Patagonia; North Atlantic
• Online Access: https://doi.org/10.1029/2023GL104805; https://doaj.org/article/ce6ae8efec3d40c1975b0799f27a4157

Abstract Proxy reconstructions and model simulations of precipitation during Earth's glacial periods suggest that the locations and mechanisms of atmospheric moisture transport have changed considerably during Earth's past. We investigate the hydroclimate of the Last Glacial Maximum (LGM) using simulations with the Community Earth System Model, with a focus on the extratropics and the influence of atmospheric rivers (ARs), a key driver of modern‐day moisture transport globally. Mean and extreme precipitation increase significantly over southwestern Patagonia, Iberia, and southwestern North America—mid‐latitude regions affected by ARs in the modern climate—despite overall decreases elsewhere. In each, the associated moisture transport changes are different, with increased transport and AR activity mainly occurring in the North Atlantic. The overall LGM response is dominated by the response to ice sheets, with other forcings causing additional cooling and drying over the extratropics and a strong decrease of moisture transport over the subpolar North Atlantic.