兰江流域降雨量与气候指数的相关性研究

Three climate indexes, including Pacific Decal Oscillation (PDO), Southern Oscillation Index (SOI) and East Asian Summer Monsoon Index (EASMI), interpolated to daily values using spline interpolation method, were analyzed with daily precipitation from 28 meteorological stations over Lanjiang River Basin from 1963 to 2000 in order to investigate the correlation of precipitation and climate indexes. Both linear regression and multiple regression were adopted. The PDO index was investigated for the long-term relationship and the SOI index was investigated for both long and short term. The EASMI was only investigated for short term relationship. Results show that there is significant long-term positive correlation between precipitation and PDO, and the correlation in Jinhua subbasin was more significant than that in Qu subbasin. On long-term correlation, SOI is negatively correlated to precipitation with a correlation coefficient greater than 0.2. For short-term correlation, SOI and EASMI are negatively related to precipitation, and the correlation is more significant for EASMI since it is a regional-based index. Especially for Qu subbasin, a correlation coefficient up to 0.5 is found for EASMI when PDO is in warm phase. According to investigation at different subperiods defined by PDO phases, SOI and EASMI exhibite more significant correlation with PDO in warm phase. Furthermore, multiple regression results show that index combination of SOI, PDO and EASMI can significantly increase the correlation with precipitation, especially the PDO-SOI combination with correlation coefficient up to 0.39 for Jinhua subbasin and 0.28 for Qu subbasin, respectively.