Changing seasonality of daily and monthly precipitation extremes for the contiguous USA and possible connections with large‐scale climate patterns
Changing seasonality of daily and monthly precipitation extremes for the contiguous USA and possible connections with large‐scale climate patterns
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DOI：
10.1002/joc.7994
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
N. Dhakal;Bhikhari Tharu;Ali Aljoda
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文献类型：
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作者：
N. Dhakal;Bhikhari Tharu;Ali Aljoda
极端降水季节性的时间变化，以及极端降水季节性与大尺度气候模式之间可能的遥相关还没有得到很好的理解。在本研究中，我们调查了1951-2014年期间美国本土1，108个站的年日最大（ADM）和月最大（MM）降水指数季节性的时间变化。我们还研究了极端降水的季节性在负和正阶段的三个主要振荡：厄尔尼诺-南方涛动，北方大西洋涛动，太平洋年代际振荡。我们的研究结果表明，许多气候区域内的连续美国表现出明显的季节性ADM和MM。两个历史记录的相等长度，即1981年之前和之后的季节性比较，显示出很大的空间变异性，在整个连续的美国。虽然在一个大面积的极端降水发生的平均日期的变化的空间一致性是不可见的，最近一段时间的季节性强度下降的一组站点集中在东部墨西哥湾沿岸和东北和西北地区的沿海站点。在三个气候指数的负和正阶段期间的极端降水季节性表明，大尺度气候变率对极端降水发生的平均日期有很大的影响，但对邻近美国的季节性强度的影响一般很弱。我们的研究结果可能有助于可持续的水资源管理，洪水风险缓解，并预测未来的降水季节性。
Temporal changes in the seasonality of extreme precipitation, and possible teleconnections between the seasonality of extreme precipitation and large‐scale climate patterns are not well understood. In this study, we investigated temporal changes in seasonality of annual daily maximum (ADM) and monthly maximum (MM) precipitation indices over the period 1951–2014 for 1,108 stations across the contiguous USA. We also examined seasonality of extreme precipitation during negative and positive phases of three major oscillations: the El Niño–Southern Oscillation, the Northern Atlantic Oscillation, and the Pacific Decadal Oscillation. Our results show that many climate regions within the contiguous USA display distinct seasonality for both ADM and MM. Comparison of seasonality between two historical records of equal length, that is, before and after 1981, shows great spatial variability across the contiguous USA. While a spatial coherence of change in the mean date of occurrence of extreme precipitation across a large area is not visible, a cluster of stations showing decrease in strength of seasonality for the recent period is concentrated in the eastern Gulf Coast and coastal sites of Northeast and Northwest regions. Extreme precipitation seasonality during negative and positive phases of three climate indices revealed that large‐scale climate variabilities have a strong influence on the mean date of occurrence of extreme precipitation but generally weak influence on the strength of seasonality in the contiguous USA. Results from our study might be helpful for sustainable water resource management, flood risk mitigation, and prediction of future precipitation seasonality.