斜压环状模调控全球大气河与极端降水
Baroclinic Annular Mode Modulates Global Atmospheric Rivers and Extreme Precipitation
查看机构详情
- Purdue University（普渡大学）
- Boston College（波士顿学院）
机构由 AI 辅助整理，请以论文原文为准。
浏览论文内容
中文总结 AI 辅助
该研究揭示斜压环状模（BAM）通过重组大气河路径和极端降水分布，成为连接大尺度环流与全球水文极端事件的关键模态。
中文摘要 AI 辅助
斜压环状模（BAM）强烈影响中纬度环流，但其在全球水文循环中的作用仍不清楚。利用ERA5再分析资料和全球大气河（AR）数据库，我们表明BAM系统地重组了南北半球的大气河发生和极端降水。在高BAM状态下，大气河频率沿主要风暴路径的侧翼增加，而在其气候核心附近减少，从而重新分配了偏好的大气河走廊。相对大气河频率变化局部超过50%，其中南大洋上空的纬向一致型态最为显著。极端降水相应变化，第99百分位降水发生频率在广阔的向极风暴路径区域增加超过50%。这些极端事件中有很大一部分与大气河同时发生，且与大气河相关的极端降水表现出类似的BAM相关调制。低BAM状态大体呈现相反的异常。这些结果将BAM确定为连接大尺度环流与全球水分输送及水文极端事件的关键模态。
英文摘要
The Baroclinic Annular Mode (BAM) strongly influences extratropical circulation, yet its role in the global hydrological cycle remains unclear. Using ERA5 reanalysis and a global atmospheric river (AR) database, we show that BAM systematically reorganizes AR occurrence and extreme precipitation in both hemispheres. During high-BAM states, AR frequency increases along the flanks of major storm tracks and decreases near their climatological cores, redistributing preferred AR corridors. Relative AR-frequency changes locally exceed 50%, with the most zonally coherent patterns over the Southern Ocean. Extreme precipitation varies correspondingly, with 99th-percentile precipitation occurrence increasing by more than 50% across broad poleward storm-track regions. A large fraction of these extremes coincide with ARs, and AR-associated extreme precipitation shows similar BAM-related modulations. Low-BAM states show broadly opposite anomalies. These results identify BAM as a key mode linking large-scale circulation to global moisture transport and hydrological extremes.
