Increased Fall Precipitation in the Southeastern United States Driven by Higher‐Intensity, Frontal Precipitation
Increased Fall Precipitation in the Southeastern United States Driven by Higher‐Intensity, Frontal Precipitation
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DOI：
10.1029/2019gl083177
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发表时间：
2019-07
影响因子：
5.2
通讯作者：
D. Bishop;A. P. Williams;R. Seager
中科院分区：
文献类型：
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作者：
D. Bishop;A. P. Williams;R. Seager
1895 - 2018年期间，由于北大西洋副热带高压周围环流增加，加强了进入该地区的水汽输送，墨西哥湾以北的美国东南部降水增加了近40%。我们在这里发现，美国东南部秋季降水的增加几乎完全表现为降水强度的增加，而不是频率的增加。此外，水汽输送的增强对降水总量的增加在最高强度降水日的作用远大于在低强度降水日的作用，导致几乎所有的增加都发生在极端（强度前5%）降水日。秋季降水增加的87%是由非热带风暴（主要是锋面）驱动的，而不是热带气旋，尽管两种风暴类型的降水比例没有变化。需要进一步的研究来评估这些观测到的降水增加是否有可能继续、稳定或逆转。
During 1895‐2018, fall precipitation increased by nearly 40% in the southeastern United States north of the Gulf of Mexico due to increased circulation around the western North Atlantic Subtropical High, which enhanced moisture transports into the region. We find here that these increases in southeastern U.S. fall precipitation manifested almost entirely as increases in precipitation intensity, not frequency. Further, the enhanced moisture transports increased precipitation totals far more on the highest‐intensity precipitation days than on the lower‐intensity days, leading to nearly all of the increase to be delivered on extreme (top‐5% intensity) precipitation days. Eighty‐seven percent of the fall precipitation increase was driven by non‐tropical storms (mostly frontal), not tropical cyclones, though the proportion of precipitation falling as either storm type did not change. Further research is needed to evaluate whether these observed precipitation increases are likely to continue, stabilize, or reverse.