西太平洋副高的年际变化及其对我国东部夏季降水的影响

利用国家气候中心给出各项西太平洋副高指数、我国东部地区108个测站逐月降水量和同期NCEP/NCAR再分析月平均高度场网格资料,分析了500 hPa西太平洋副高的年际变化特征,并通过SVD方法分析500 hPa西太平洋副高年际变化对我国东部地区降水的影响。结果表明,500 hPa西太平洋副高的面积指数和强度指数均具有准2年的周期。副高的年际变化对我国东部降水分布空间型有显著影响,第1对空间分布型的方差贡献达56%,可知副高北抬是导致我国东部夏季降水呈"-+-"的主要原因。

Interannual Variability of the Western Pacific Subtropical High and Its Impact on Summer Precipitation in Eastern China

Using the Western Pacific subtropical high index supplied by the National Climate Center,the monthly precipitation of the eastern China 108 stations and the monthly average height field grid data of NCEP/NCAR reanalysis in same period,the interannual variability of the 500 hPa west Pacific subtropical high was analyzed and the effect of 500 hPa west Pacific subtropical high on the precipitation in eastern China was analyzed by SVD method.The results showed that the area index and intensity index of the 500 hPa west Pacific subtropical high had quasi -2-year cycles.The interannual variation of the subtropical high had a significant effect on the spatial distribution of precipitation in eastern China.The first contribution to the spatial distribution of the variance was 56％.It could be seen that the north elevation of the subtropical high was the main reason for fluctuation change of the summer precipitation in eastern China.