The Climatological Impact of Recurving North Atlantic Tropical Cyclones on Downstream Extreme Precipitation Events
The Climatological Impact of Recurving North Atlantic Tropical Cyclones on Downstream Extreme Precipitation Events
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北大西洋回归热带气旋对下游极端降水事件的气候影响
DOI：
10.1175/mwr-d-18-0195.1
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发表时间：
2019
影响因子：
3.2
通讯作者：
O. Martius
中科院分区：
文献类型：
--
作者：
Roman Pohorsky;M. Röthlisberger;C. Grams;J. Riboldi;O. Martius
这项研究首次对北大西洋热带气旋下沉对下游极端降水的影响进行了气候学评估。根据1979至2013年间146个下弯TC的滞后合成来评估响应，并通过相对于TC-JET相互作用位置移动的区域中的极端降水影响区域(PEA)来量化，TC-JET相互作用位置通常包括欧洲大部分地区。利用一种基于流动模拟的新的自举技术来确定PEA对TCS的响应的统计意义。在TC-JET相互作用后的+42小时和+90小时之间，PEA在统计上显著增加，与没有TCS复发的模拟病例相比，PEA增加了一倍。对热带气旋-急流相互作用点附近位涡[ln(Pv)]的自然对数进行K-均值聚类，揭示了北大西洋气旋-急流相互作用的四种主要流动形态。下弯的热带气旋可以在更远的下游形成降水极值的两个主要机制：1)“大气河状”机制，在下弯的气旋中心下游具有异常高的综合水汽输送(IVT)；和2)“下游发展”机制，在下游低谷之前具有异常高的IVT。因此，模拟自举技术将热带气旋和中纬度气流的自然演变对PEA形成的影响分开。这一分析表明，对于大气河流状的情况，热带气旋的影响是明确的，而对于下游发展的情况，在没有热带气旋的情况下，PEA也显著增加。
This study provides the first climatological assessment of the impact of recurving North Atlantic tropical cyclones (TCs) on downstream precipitation extremes. The response is evaluated based on time-lagged composites for 146 recurving TCs between 1979 and 2013 and quantified by the area affected by precipitation extremes (PEA) in a domain shifted relative to the TC–jet interaction location, which often encompasses major parts of Europe. The statistical significance of the PEA response to the TCs is determined using a novel bootstrapping technique based on flow analogs. A statistically significant increase in PEA is found between lags +42 and +90 h after the TC–jet interaction, with a doubling of the PEA compared to analog cases without recurving TCs. A K-means clustering applied to the natural logarithm of potential vorticity fields [ln(PV)] around the TC–jet interaction points reveals four main flow configurations of North Atlantic TC–jet interactions. Two main mechanisms by which recurving TCs can foster precipitation extremes farther downstream emerge: 1) an “atmospheric river–like” mechanism, with anomalously high integrated vapor transport (IVT) downstream of the recurving TCs and 2) a “downstream-development” mechanism, with anomalously high IVT ahead of a downstream trough. Hereby, the analog bootstrapping technique separates the impact of the TC from that of the midlatitude flow’s natural evolution on the PEA formation. This analysis reveals an unequivocal effect of the TCs for the atmospheric river–like cases, while for the downstream-development cases, a substantial increase in PEA is also found in the analogs without a TC.
影响因子：
8.9
作者：
C. Grams;H. Wernli;M. Böttcher;J. Čampa;U. Corsmeier;S. Jones;J. Keller;C. Lenz;L. Wiegand-
通讯作者：
C. Grams;H. Wernli;M. Böttcher;J. Čampa;U. Corsmeier;S. Jones;J. Keller;C. Lenz;L. Wiegand-