Precipitation Patterns During the "Dragon Boat Water" in South China for the Recent 49 Years
Precipitation Patterns During the "Dragon Boat Water" in South China for the Recent 49 Years
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发表时间：
2013
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通讯作者：
H. Yami
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作者：
H. Yami
利用旋转经验正交函数(REOF)方法，分析了1961-2009年“龙舟水”期间的降水形势，并采用线性趋势估计、经验模式分解(EMD)、Morlet小波分析和Mann-Kendall检验等方法对其时空特征进行了分析。结果表明，东南沿海、北部沿海和西南沿海分别存在3种偏好的降水型，且均表现出6~8年的周期振荡。近49年来，东南沿海降水量呈减少趋势，而北部和西南沿海呈增加趋势。结果表明，东南沿海降水量呈下降趋势，而北部和西南沿海呈增加趋势。20世纪90年代中期以来，降水“龙舟水”在北方地区出现频率较高，东南、西南沿海近几年降水呈正异常，东南沿海和北部地区分别在70年代中期和90年代初出现了两次突变，而西南沿海没有明显变化。最后，从西北太平洋副热带高压、阻塞高压、季风槽、低层切变、垂直速度和水汽输送总量等方面比较了不同的大气环流特征。
Based on the rotated empirical orthogonal function(REOF) method,the precipitation patterns during the "Dragon Boat Water" from 1961 to 2009 are analyzed.What's more,the spatial and temporal characteristics are discussed by adopting linear tendency estimation,experimental mode decomposition(EMD),Morlet wavelet analysis and Mann-Kendall test.The results show that there are three kinds preferred precipitation patterns in Southeast Coast,the North region and Southwest Coast,respectively,and all of them show 6 — 8 year periodic oscillations.Southeast Coast has decreasing trend in precipitation,while the North region and Southwest Coast share an increasing trend in the past 49 years.However,the precipitation "dragon boat water" has occurred more frequently in the North region since mid 1990s,and the rainfalls in Southeast and Southwest Coast have shown positive anomalies in recent several years.Two abrupt jumps occurred in mid 1970s and early 1990s in Southeast Coast and the North region,respectively,but there was no obvious change in Southwest Coast.Finally,the different atmospheric circulation features are compared from the aspects of Northwest Pacific subtropical high,blocking high,monsoontrough,low layer shear,vertical velocity speed and the total water vapor transport.