de Vries Andries Jan, Armon Moshe, Klingmüller Klaus, Portmann Raphael, Röthlisberger Matthias, Domeisen Daniela I V
Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland.
Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland.
Commun Earth Environ. 2024;5(1):493. doi: 10.1038/s43247-024-01633-y. Epub 2024 Sep 20.
More than a third of the world's population lives in drylands and is disproportionately at risk from hydrometeorological hazards such as drought and flooding. While weather systems governing precipitation formation in humid regions have been widely explored, our understanding of the atmospheric processes generating precipitation in arid regions remains fragmented at best. Here we show, using a variety of precipitation datasets, that Rossby wave breaking is a key atmospheric driver of precipitation in arid regions worldwide. Rossby wave breaking contributes up to 90% of daily precipitation extremes and up to 80% of total precipitation amounts in arid regions equatorward and downstream of the midlatitude storm tracks. The relevance of Rossby wave breaking for precipitation increases with increasing land aridity. Contributions of wave breaking to precipitation dominate in the poleward and westward portions of arid subtropical regions during the cool season. Our findings imply that Rossby wave breaking plays a crucial role in projections and uncertainties of future precipitation changes in societally vulnerable regions that are exposed to both freshwater shortages and flood hazards.
世界上超过三分之一的人口生活在干旱地区，他们面临干旱和洪水等水文气象灾害的风险尤其高。虽然在湿润地区控制降水形成的天气系统已得到广泛研究，但我们对干旱地区产生降水的大气过程的了解充其量仍支离破碎。在此，我们利用各种降水数据集表明，罗斯贝波破碎是全球干旱地区降水的关键大气驱动因素。在中纬度风暴路径赤道一侧和下游的干旱地区，罗斯贝波破碎对每日极端降水量的贡献高达90%，对总降水量的贡献高达80%。罗斯贝波破碎对降水的相关性随着土地干旱程度的增加而增强。在凉爽季节，波破碎对降水的贡献在干旱亚热带地区的极地和西部部分占主导地位。我们的研究结果表明，罗斯贝波破碎在面临淡水短缺和洪水灾害的社会脆弱地区未来降水变化的预测和不确定性中起着关键作用。
