The role of eastern North Pacific tropical storms in the rainfall climatology of western Mexico
The role of eastern North Pacific tropical storms in the rainfall climatology of western Mexico
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DOI：
10.1002/joc.637
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发表时间：
2001-09-01
期刊：
影响因子：
--
通讯作者：
Douglas, AV
中科院分区：
文献类型：
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作者：
Englehart, PJ;Douglas, AV
本文探讨了北太平洋东部热带风暴（TS）在墨西哥西部降雨气候学中的作用。它使用了一个18个站点的降雨网格，以及一个1949-1997年的风暴路径数据库。TS降雨量由距离阈值定义，因此对于网格中的每个站点，当TS位于该站550公里范围内时记录的日降雨量被视为TS衍生；在没有TS信号的情况下，或风暴距离气象站超过550公里时所录得的雨量，默认为“非TS”雨量。提出了各种统计数据来证明TS活动与区域降雨模式之间存在静态关联。总之，他们清楚地表明，改进北太平洋东部TS活动的季节性预测对于推进墨西哥的季节性气候预测至关重要。本研究还讨论了TS和非TS降雨的年际变化。主成分分析用于确定该地区降雨变化的主要模式。考虑到降雨模式的时间行为，分析显示TS降雨在统计上没有显著的趋势。相反，非ts降雨模式表现出显著的趋势。这项研究支持了这样一种观点，即这些趋势部分与海洋-大气系统的长期波动有关。结果还表明，虽然TS降雨不受趋势行为的影响，但其逐年波动显然与厄尔尼诺-南方涛动（ENSO）和北太平洋海面温度（SSTs）等大规模过程有关。版权所有(C) 2001英国皇家气象学会。
This paper explores the role that tropical storms (TS) of the eastern North Pacific play in the rainfall climatology of western Mexico. It uses an 18-station rainfall grid, along with a data base of storm tracks (1949-1997). TS rainfall is defined by a distance threshold, so that for each station in the grid, daily rainfall recorded when a TS is located within 550 km of the station is considered as TS-derived; rainfall recorded in the absence of a TS or when a storm is beyond 550 km from a station is by default 'non-TS' rainfall. A variety of statistics are presented to demonstrate the static associations that exist between TS activity and regional rainfall patterns. In sum, they clearly suggest that improved seasonal forecasts of TS activity in the eastern North Pacific will be critical to advancing seasonal climate prediction for Mexico. This study also addresses the interannual variability in TS and non-TS rainfall. Principal component analysis is used to define the region's primary modes of rainfall variation. Considering the temporal behaviour of the rainfall modes, analyses reveal no statistically significant trends in TS rainfall. In contrast, non-TS rainfall modes exhibit significant trends. This study provides support for the idea that these trends are partly tied to long-period fluctuations in the ocean-atmosphere system. The results also indicate that while TS rainfall is not subject to trend behaviour, its year-to-year fluctuations, apparently, are linked to large-scale processes like El Nino-Southern Oscillation (ENSO) and the state of North Pacific sea-surface temperatures (SSTs). Copyright (C) 2001 Royal Meteorological Society.