基于马尔科夫链模型的鄱阳湖流域水文气象干旱研究

Changing properties of meteor-hydrological droughts of the Lake Poyang Basin using the Markov model

基于气象和水文干旱的二维变量干旱状态基础上,通过一阶马尔科夫链模型对二维变量干旱状态进行频率、重现期和历时分析,建立水文气象干旱指数,从干旱灾害形成、演变和持续3方面对干旱灾害进行研究,同时预测未来6个月非水文干旱到水文干旱的概率.结果表明:(1)修河流域在干旱形成中危害大,抚河流域和修河流域在干旱演变中危害大,赣江流域和饶河流域在干旱持续中危害大;(2)鄱阳湖流域状态4(气象、水文干旱)发生的频率最高,为0.30,连续湿润或者干旱的概率最大,湿润状态(状态2)与水文干旱(状态4、状态5(气象湿润、水文干旱))的相互转移概率最低;(3)在长期干旱预测中,鄱阳湖流域从状态2转到状态4和状态5的平均概率为0.11,属最低,而状态1(气象、水文无旱)和状态3(气象干旱、水文湿润)到达状态4的概率为0.23,发生概率最大.修河流域在非水文干旱状态下未来发生气象、水文干旱状态的平均概率为0.28,是"五河"中最高的,而赣江流域在正常或者湿润状态下未来发生气象、水文干旱的概率最低,为0.18,该研究对于鄱阳湖流域水文气象干旱的抗旱减灾具有重要理论与现实意义.

Combined analysis of precipitation and water scarcity was done with using SPI and SRI indices. Time series of the hydro-meteorological conditions were investigated as discrete state, discrete-time Markov chain with aim to explore transition be- tween drought conditions in terms of frequency, residence time, and interim period from one drought condition to another. Besides, prediction of drought conditions were also conducted. The results indicate that ： （ 1 ） The drought hazards do have its massive nega- tive impacts during its initial conditions in the Xiuhe River basin ; and manifest its negative impacts during its developing conditions of the droughts in the Fuhe and Xiuhe River basins; in the Ganjiang and Raohe River basins, however, the droughts have its grea- test impacts during lasting time intervals ; （ 2 ） The occurrence probability of meteor-hydrological droughts of the Poyang Lake is characterized by continuing wet or dry conditions. Transition between meteorological wetness to hydrological drought is subject to lower probability in the Lake Poyang Basin ; （ 3 ） The prediction of droughts indicates that the transitional probability from the 2nd condition to hydrological drought is the lowest and the transitional probability from the 1st （ or 3rd） condition to the 4th condition is the largest. The transitional probability from the 1 st, 2nd and 3rd condition to hydrological drought is the lowest in Xiuhe River Basin. However, The transitional probability from the 1 st and 2nd condition to hydrological drought is the largest in Ganjiang River Basin The results of this study will be of great merits in terms of human mitigation to droughts in a changing environment.