The Pacific Walker circulation and the closely connected El Niño/Southern Oscillation influence the climate and weather of the tropical Indo-Pacific region. They specifically exert a strong control on the regional occurrence of weather extremes, such as heatwaves, heavy precipitation and prolonged dry spells, which are becoming increasingly frequent and severe. However, climate models struggle to accurately simulate large-scale circulation changes in the tropics and thus their consequences for regional weather and future climate. Here we use high-resolution ERA5 reanalysis data from 1940 to 2022 to study the occurrence trends of weather patterns in the tropical Indo-Pacific region. We find that new large-scale synoptic situations that were rarely present before the 1990s have emerged in the Indo-Pacific, while some others that were prominent have disappeared. Those new synoptic situations are associated with an unusual proportion of heatwaves and extreme precipitation in the region. These weather patterns are physically consistent with a trend towards a stronger Pacific Walker circulation, wetter and warmer conditions in Southeast Asia and drier conditions in the equatorial Pacific. These changes cannot be fully explained by El Niño/Southern Oscillation and other relevant modes of interannual variability, and other factors such as global warming, aerosol forcing, external forcing mechanisms and nonlinear mode interactions may be contributing.

太平洋沃克环流和密切相关的厄尔尼诺/南方涛动影响热带印太地区的气候和天气。它们特别对极端天气的区域性发生施加了强有力的控制，例如热浪、强降水和长时间干旱，这些天气变得越来越频繁和严重。然而，气候模型难以准确模拟热带地区的大尺度环流变化，从而模拟它们对区域天气和未来气候的影响。在这里，我们使用 1940 年至 2022 年的高分辨率 ERA5 再分析数据来研究热带印太地区天气模式的发生趋势。我们发现，在 1990 年代之前很少出现的新的大规模天气情况在印太地区出现，而其他一些突出的情况已经消失。这些新的天气情况与该地区不寻常比例的热浪和极端降水有关。这些天气模式在物理上与太平洋沃克环流更强、东南亚更潮湿和更温暖的条件以及赤道太平洋更干燥的条件的趋势一致。这些变化不能完全用厄尔尼诺/南方涛动和其他相关的年际变率模式来解释，其他因素如全球变暖、气溶胶强迫、外部强迫机制和非线性模式相互作用也可能是其中的原因。