Abstract:

According to the temperature and precipitation data of 21 meteorological stations which lie in Henan province during 1960-2013, by using the trend line, Mann-Kendall mutation test, Z index, markov model, empirical orthogonal function, we analyzed the climate change and its influence on drought/flood in Henan province. It turned out that: (1) The temperature presented a trend of increasing in Henan province, and the temperature mutation point is 1997. The annual precipitation showed a trend of weak decreasing. The temperature reduced gradually from south to north, and the central region presented a trend of increasing significantly. The annual precipitation reduced gradually from southeast to northwest, and the central-eastern region presented a trend of increasing, but north, west and south showed a trend of decreasing. (2) The trend of drought was increasing in Henan province. The climate change and drought and flood occurred with synchronicity. After the temperature mutations, the frequency of extreme flood reduced significantly, but the frequency of extreme drought increased significantly. Using markov model, we predict the trend of drought and flood change over time, the probability of normal is the largest, and the probability of drought is greater than the flood. (3) The main spatial distribution of drought and flood is the same phase of all, the reverse phase of north and south, the reverse phase of east and west. The interannual tendency of the drought/flood and the precipitation were almost the same. In spring, the trend of drying was gradually serious from north to south; in summer, the trend of humidifying reduced gradually from Xihua-Nanyang toward southeast and northwest respectively; in autumn, the whole area presented a trend of dry; in winter, the trend of humidifying was gradually serious from southwest to northeast.

Key words: climate change, drought/flood, Z index, markov model, empirical orthogonal function