China's Top Ten Rivers In Precipitation And Temperature Long-term Change In Trend

Water resource is the source of life. It is the basic condition to the development of the economy and society. With the increase of the population and the improvement of the economy, the whole world need more and more water. For this reason, it has much important meaning to analysis the water resource's long term change of rule and to predict its trend in the future.Ten river basins include Songhuajiang River Basin, Liaohe River Basin, Haihe River Basin, Yellow River Basin, Huaihe River Basin, Yangtse Rive Basin, South-East Area, Zhujiang River Basin, South-west Area and North-west Area of China. In this paper, in order to analysis the water resource's long term change of rule we have studied the monthly and seasonal precipitation data from 1881 to 2002 and monthly temperature data from 1951 to 2002 of ten river basins of China by using the historical trending chart, the power spectrum analysis method and the wavelet analysis method. The results indicate that the precipitation distribution of ten river basins is quite different from place to place since the middle and late of 1990s. There is less rain in Songhuajiang River Basin, Liaohe River Basin, Haihe River Basin, Yellow River Basin and Huaihe River Basin in the north of China and there is more rain in the south of China and the north-west area of China. The results also indicate that there is obvious inter-decadal precipitation variation in each area. The rainfalls period of Songhuajiang River Basin, Liaohe River Basin, Yangtse Rvier Basin and Zhujiang River Basin is about 27~38 years. By analyzing the cause of precipitation in Haihe River Basin and Yellow River Basin, we have found that precipitation in Haihe River Basin and Yellow River Basin is influenced by some factors including atmosphericinternal dynamic processes and thermodynamic processes and external forcing. The results reveal that the precipitation in Haihe River Basin and Yellow River Basin has a very good relationship with the SST in Equatorial Pacific, the snow cover over Qinghai-Tibet Plateau from winter to spring, the intensity and position of the subtropical high in the Western Pacific and the large-scale circulation in the northern hemisphere. Therefore, we consider that the precipitation abrupt change in Haihe River Basin and Yellow River Basin occurring in the middle of 1970s was caused by these reasons.From above discussion, we make a preliminary prediction that the precipitation distribution which is more in the south China and less in the north China will still maintain for a period of time. During 2010~2020 probably there is a transition of ten river basins precipitation distribution. The time of each basin's transition is decided by its influence factors.According to the long term change of rule of temperature in ten basins, it can be classified into three types: "cold-warm", "warm-cold-warm" and "warm-cold". The result reveals that during the next 10-20 years the temperature in south-west area of China will change from cold period into warm period and other basins will still maintain warm period and probably enter into cold period in the late of period.