Increased amplitude of atmospheric rivers and associated extreme precipitation in ultra-high-resolution greenhouse warming simulations

Atmospheric rivers (ARs) play an integral role in the global water cycle. Despite great advances in understanding ARs over the last several decades, considerable uncertainties remain in estimating future AR changes, originating from large inter-model and inter-detection-method differences. Using ultra-high-resolution Community Earth System Model simulations and a novel AR detection algorithm based on geometric shape extraction, we quantify global changes in ARs and the associated precipitation events in response to atmospheric $CO_2$ doubling and quadrupling. On a global scale, ARs are projected to become more frequent and more likely to be associated with extreme precipitation events, resulting in a higher contribution of AR precipitation to global mean precipitation. The mean changes in AR frequency in a warmer climate are mainly driven by the underlying circulation systems while the AR properties like precipitation and water vapor transport follow the Clausius-Clapeyron relationship. The increased amplitude of ARs and associated mean and extreme precipitation has an important implication for future water management and adaptation policies