Torrential rain associated with Typhoon Hagibis (2019) caused extensive destruction across Japan. To project future changes of the record-breaking rainfall, numerical experiments using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model were conducted in current (CNTL) and pseudo-global warming (PGW) climates. The water vapor mixing ratio in the lower troposphere increased by 23% in response to a 3.34 K increase in sea surface temperature (SST) in the PGW climate. The abundant moisture supply by the westward winds of the typhoon caused strong precipitation from its rainbands for a long period, resulting in 90% increase in total precipitation in eastern Japan before landfall. However, the strong PGW typhoon caused high SST-cooling. Mean precipitation in eastern Japan during the typhoon passage increased by 22% when the SST-cooling east of Kanto was strengthened from 0.11 K to 0.72 K from the CNTL to PGW simulations; the increase was above 29% when the SST-cooling was lowered.

Since Typhoon Hagibis accelerated as it traveled northward, the magnitude of the SST-cooling and weakening of the typhoon were suppressed. Consequently, strong precipitation in the inner-core of the strong PGW typhoon caused 30% increase in precipitation in the areas on the Pacific side of northern Japan.

与台风海贝思 (2019) 相关的暴雨在日本造成了广泛的破坏。为了预测破纪录降雨的未来变化，在当前（CNTL）和伪全球变暖（PGW）气候中使用区域 1 公里网格三维大气-海洋耦合模型进行了数值实验。在 PGW 气候中，对流层低层的水汽混合比增加了 23%，以响应海面温度 (SST) 增加 3.34 K。台风西风补给丰富的水分，导致其雨带长期强降水，登陆前日本东部降水总量增加90%。然而，强烈的PGW台风导致了高海温降温。当关东以东海温从 0.11 K 增强到 0.72 K 时，台风通过期间日本东部的平均降水量增加了 22%；当 SST 冷却降低时，增加超过 29%。

由于台风海贝思在向北移动时加速，因此台风的海温变冷和减弱的幅度受到抑制。因此，强PGW台风核心区的强降水导致日本北部太平洋一侧地区的降水量增加了30%。