利用19812010年中国西南地区气象站点逐日降水资料以及NCEP/NCAR逐日再分析资料, 使用MTM-SVD方法分析了西南地区降水的季节内振荡特征, 结果表明: 西南地区降水存在显著的14.4候(70天左右)振荡周期, 该季节内振荡在1985年前后最强, 在整个研究时段内夏季更明显.典型循环重建表明, 西南地区降水的季节内振荡整体上有一个从南向北的推进过程, 对OLR的分析表明, 南海—西太平洋地区和孟加拉湾地区是影响西南地区降水的两个关键区.在季节内振荡尺度上影响西南地区降水的OLR异常信号首先出现在爪哇岛附近, 逐渐向东传播到马鲁古群岛地区, 然后北跳传播到北半球的南海—西太平洋地区和孟加拉湾地区, 最后两者先后向北推进影响西南地区降水.
Based on the daily precipitation data from the meteorology stations in southwest China and the NCEP/NCAR reanalysis daily data from 1981 to 2010, using the method of Multi Taper Method-Singular Value Decomposition (MTM-SVD), the characteristic of the precipitation interseasonal oscillation was analyzed. The results show that precipitation in southwest China have significant 14.4 pentads period (70 days). The Intraseasonal Oscillation(ISO) is the strongest around 1985, embodied in the summer of the entire study period. The typical revasculization pointed out that there is an advance from the south to the north of precipitation ISO in southwest China. The OLR analysis shows that the South China Sea—West Pacific and the Bay of Bengal are two key areas affecting precipitation in southwest China. Further analysis showed that the OLR abnormal signal first appeared near the island of Java, the anomaly gradually eastward propagation to the Maluku Islands, and abnormal spread to the South China Sea—West Pacific and the Bay of Bengal region, both next successively northward affect precipitation in Southwest China.
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