Wavelet and scaling analysis of monthly precipitation extremes in Germany in the 20th century: Interannual to interdecadal oscillations and the North Atlantic Oscillation influence
Wavelet and scaling analysis of monthly precipitation extremes in Germany in the 20th century: Interannual to interdecadal oscillations and the North Atlantic Oscillation influence
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DOI：
10.1029/2004wr003843
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发表时间：
2005-09
影响因子：
5.4
通讯作者：
D. Markovic;M. Koch
中科院分区：
文献类型：
--
作者：
D. Markovic;M. Koch
使用连续小波工具对德国各地测量站的月降水极值进行了研究，以实现方差和频率-时间定位以及主要振荡的检测。除1年的高频振荡外，月降水极值在年际（7 - 8年）和/或年代际（11 - 14年）低频尺度上表现出增强的能量，特别是在世纪后半叶，这为德国的某些区域气候变化提供了证据。应用去趋势波动分析（DFA），通过计算Hurst参数确定降水时间序列的标度特性。很明显，具有低频分量的数据，无论是否显著，都显示出更高的Hurst参数值，也就是说，一定程度的持久性，而不是没有这些分量的数据。通过对尺度平均小波功率和交叉小波谱的分析，发现北大西洋涛动对降水模式的遥相关影响的证据，主要是在过去40年中，并且在德国的北方和南部地区有部分相反的影响。北大西洋涛动增强的年代际变率阶段被证明是低频降水分量的原因。
Monthly precipitation extremes from gauging stations across Germany were studied using continuous wavelet tools toward variance and frequency‐time localization and detection of dominant oscillations. Apart from the high‐frequency, 1 year oscillation, the monthly precipitation extremes show enhanced power at interannual (7‐8 years) and/or interdecadal (11‐14 years) low‐frequency scales, in particular in the second part of the 20th century, providing evidence for some regional climatic changes over Germany. Applying detrended fluctuation analysis (DFA), scaling properties of the precipitation time series through the computation of the Hurst parameter are determined. It is apparent that data with low‐frequency components, regardless of whether significant or not, show higher Hurst parameter values, that is, some amount of persistence, than data without such components. Through analyses of the scale‐averaged wavelet power and the cross‐wavelet spectra, evidence for a teleconnective influence of the North Atlantic Oscillation on the precipitation pattern, primarily over the last 40 years, and with partly opposite effects in the northern and southern parts of Germany, is found. As such, the North Atlantic Oscillation phase of enhanced decadal variability was shown to be responsible for the low‐frequency precipitation components.