A sequence of torrential rainstorms pounded Pakistan in the summer of 2022, shattering records by massive margins (7 sigma). The severe socioeconomic damages underscore the urgency of identifying its dynamic drivers and relationship with human-induced climate change. Here, we find that the downpours were primarily initiated by the synoptic low-pressure systems, whose intensity and longevity far exceeded their counterparts in history as fueled by a historically-high cross-equatorial moisture transport over the Arabian Sea. The moisture transport has been trending upward since the 1960s and, in 2022, along with the anomalous easterly moisture influx caused by the combination of La Niña and negative Indian Ocean Dipole events, created a corridor of heavy rainfall extending from central India toward southern Pakistan. While it is not yet established whether the observed trend of the cross-equatorial moisture transport has exceeded natural variability, model-based analysis confirms that it is consistent with the fingerprint of anthropogenic climate warming and will raise the likelihood of such rare events substantially in the coming decades.

2022 年夏天，一系列暴雨袭击了巴基斯坦，大幅打破了纪录（7 西格玛）。严重的社会经济损失凸显了确定其动态驱动因素及其与人为气候变化的关系的紧迫性。在这里，我们发现，倾盆大雨主要是由天气低压系统引发的，其强度和持续时间远远超过历史上的同类系统，这是由阿拉伯海上空历史最高的跨赤道水汽输送推动的。自 1960 年代以来，水汽输送一直呈上升趋势，2022 年，加上拉尼娜现象和印度洋偶极子负事件共同引起的异常东风水汽流入，形成了一条从印度中部延伸至巴基斯坦南部的强降雨走廊。虽然尚未确定观测到的跨赤道水汽输送趋势是否超过了自然变化，但基于模型的分析证实，它与人为气候变暖的指纹一致，并将大大增加在该地区发生此类罕见事件的可能性。未来几十年。