Exploring changes of precipitation extremes under climate change through global variable-resolution modeling

Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems. Here we take the record-breaking precipitation over China in 2021 as an example, and study its changes under three different climate scenarios through a developed pseudo-global-warming (PGW) experimental framework with 60–3 km variable-resolution global ensemble modeling. Compared to the present cli- mate, the precipitation extreme under a warmer (cooler) climate increased (decreased) in intensity, cov- erage, and total amount at a range of 24.3%–37.8% (18.7%–56.1%). With the help of the proposed PGW experimental framework, we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme. Under the warmer climate, large-scale water vapor transport con- verged from double typhoons and the subtropical high marched into central China, enhancing the con- vective energy and instability on the leading edge of the transport belt. As a result, the mesoscale convective system (MCS) that directly contributed to the precipitation extreme became stronger than that in the present climate. On the contrary, the cooler climate displayed opposite changing characteris- tics relative to the warmer climate, ranging from the large-scale systems to local environments and to the MCS. In summary, our study provides a promising approach to scientifically assess the response of pre- cipitation extremes to climate change, making it feasible to perform ensemble simulations while inves- tigating the multi-scale system interactions over the globe.