Interdecadal and interannual variations of annual and extreme precipitation over central‐northeastern Argentina
Interdecadal and interannual variations of annual and extreme precipitation over central‐northeastern Argentina
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DOI：
10.1002/joc.1069
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发表时间：
2004-10
期刊：
影响因子：
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通讯作者：
O. Penalba;W. Vargas
中科院分区：
文献类型：
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作者：
O. Penalba;W. Vargas
本文分析了阿根廷中部-东北部较长的年降水时间序列，特别关注年代际和年际变化。结果显示出高度非平稳的可变性。最显著的特征是50年代前后年降水量的差异。年代际变化在西部特别明显，在研究区存在明显的线性趋势。在1910年和1930年或1940年前后，所有地区的年面平均降水均出现负距平。西部地区在1950年和1970年前后有两个较明确的负期，东部地区从1950年代开始可以观察到逐渐增加。年代际和年际变化影响了该地区年尺度和最大降水月份的极端降水行为。为了支持这些结论，使用了不同的表示方法（运行均值、功率谱分析和小波变换）。应用调和分析方法，分析了不同条件下极端降水年周期的变化规律。最潮湿的年份以年和半年周期表示，而干旱年份则需要输入频率较低的周期。版权所有©2004英国皇家气象学会
Long, annual precipitation time series from central‐northeastern Argentina are analysed with special attention to interdecadal and interannual variations. The results show a variability that is highly nonstationary. The most outstanding feature is the difference in annual precipitation before and after the 1950s. The interdecadal variability is particularly well defined in the west, and there is a significant linear trend in the study area. Negative anomalies of the areal‐averaged annual precipitation can be observed in all the areas around 1910 and 1930 or 1940. In the western zone there are two better‐defined negative periods around 1950 and 1970, and a gradual increase can be observed in the eastern zones starting in the 1950s. The interdecadal and interannual variations affect the behaviour of extreme precipitation on the annual scale and during the months with maximum precipitation in the region. In support of these conclusions, different representation methods are used (running means, power spectrum analysis, and wavelet transforms). The variations in the annual cycle of extreme precipitation under different conditions are analysed by applying harmonic analysis. The wettest years are represented by an annual and semi‐annual cycle, whereas dry years need the input of lower frequency cycles. Copyright © 2004 Royal Meteorological Society