Impacts of the North Atlantic SST on the compound extreme of south-rainstorm and north-heatwave in east of China during early summer 2022

Climate risks from compound extreme events are much greater than the sum of their sub-components. In early summer 2022, unprecedented rainstorm in South China and heatwave in North China were observed concurrently during 1979–2024 (referred to here as an SRNH event). However, most of seasonal predictions failed to capture this far-reaching SRNH event and the behind mechanisms are still unclear. The high-ranking dipole sea surface temperature anomalies in the North Atlantic (SST NA ) in February–March promoted the 2022 SRNH extreme, which was successfully verified by numerical experiments. The SST NA , highest in the recent decade, triggered the Rossby wave train, leading to record-breaking East Asian subtropical jet stream and high-level key mid-tropospheric atmospheric circulations. An anomalous anticyclonic circulation was strengthened over the Altai Mountains and North China, causing heatwave in North China. The enhanced northeast China cold vortex stabilized the western Pacific subtropical high around 20°N. The co-occurrence of the stronger Northeast cold vortex and stable western Pacific subtropical high jointly led to the rainstorm over South China in 2022. The significantly stronger dipole SST NA controlled wavier mid-latitude westerlies and southward west Pacific subtropical high, which jointly contributed to the 2022 SRNH extreme. • Record-breaking rainstorm and heatwave co-occurred in China in early summer 2022. • Wavier mid-latitude westerlies and stable subtropical high jointly caused the SRNH. • Preceding North Atlantic SST anomalies effectively stimulated SRNH compound extreme.