| Precipitation is a main part of water circulation and also the source of surface discharges. It’s spatial and temporal variation of inequality will cause flood/drought events. Runoff is the most active factor in the geographical environment, which plays an important role in flood monitoring, irrigation, navigation and power generation, etc. Since1950s, many hydraulic engineering have carried out in Min River Basin, which led to heavy changes in Luce (Land use and land cover change). So it’s necessary to analyze variation characteristics of meteorological and hydrological elements, and which will benefit to water resources development and water conservation projects in the future.In this study, based on precipitation (1960-2006a) and runoff (1950-2010a) data of Min River Basin and the modified Mann-Kendall, standardized precipitation index (SPI), empirical orthogonal function (EOF), Pearson correlation analysis were used to study the runoff trends characteristics in different time scales, spatial and temporal variation of dry/wet, and explore? the potential usefulness of SPI in Min River Basin flood/drought events monitoring. Results indicate that:(1) the annual precipitation and runoff showed positive skewness in Min River Basin;(2) due to the autocorrelation sequence widespread, TFPW-MK method is the most suitable method for runoff trend detection in Min River Basin;(3) the annual runoff trend is on the decrease between1950and2010, and the trend of flood season and spring is also ascend for most of the time, while the runoff in non-flood, summer, autumn and winter is on the increase;(4) from the time point of view, it can be seen that annual SPI has a trend towards wetter in Min River Basin, and there are mainly seven drought and eight wet events during the last47years. Except for autumn, spring, summer, winter climate dry/wet changes have trend towards wetter;(5) from the space point of view, region consistent type is the main spatial distribution of Min River Basin and the first eigenvector field of spring, summer and winter is similar to the annual distribution;(6) there are high Pearson correlations between the SPI and discharges at shorter time scales (1-3months) and the maximum correlation is found on the time scales of2months. Besides, there are important seasonal differences in the response of the river discharges to shorter time scales of Spain the correlations of spring and summer (R>0.75) are found higher than that in fall and winter (R<0.70);(7)2-month SPI can better reveal the top five ranking floods basin, especially for the two larger floods. What’s more, it also can identify major drought events and its process, which are consistent with historical data in Min River Basin. |
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