Study On Computing Methods And Its Application Of Dynamic Carrying Capacity Of Water Resources Under The Climate Change

Climate change is recognized as one of the most global environmental problems at home and abroad. Climate change has changed the watershed hydrological processes and the distribution of water resources in time and space. Together with the profound influence of human activities on the hydrology and water resources system,climate change has caused the regional imbalance of supply and demand of water resources, frequent occurrence of flood and drought and the serious damage to the natural ecological system. Future climate variation will further change the distribution of water resources in time and space, increase or reduce water consumption, thus probably affecting the change of the watershed or regional water resources carrying capacity.Climate change, to some extent, will alter the hydrological cycle process, affect the formation and transformation of water resources and then influence its system function, thus causing much more uncertainty for the development and utilization of water resources and imposing a severe challenge. River flow is influenced by both meteorological factors such as the temperature, precipitation and human activities. As for the formation and geographical distribution of runoff, the dry and wet climate condition determined by the rainfall and temperature plays an important role. The hydrologic system in the arid and semi-arid region is more sensitive to response to climate change. The impact of climate change on river basin water resources is a hotspot of research on hydrology and water resources in the world. Therefore, a study on the influence mechanism and quantitative research of climate change on hydrology and water resources system and then on the dynamic water resources carrying capacity has very important theoretical and application value.This article first summarizes the related research achievements in the field of water resources carrying capacity made by the experts and scholars at home and abroad, then puts forward the concept of dynamic water resources carrying capacity under the climate change, and expounds its connotation based on the connection between the atmospheric system and the land water resources system; The paper puts forwards the theoretical framework of computing methods of water resources carrying capacity under the climate change and PSO-COIM calculation method(“prediction-simulation-optimization-based on control goal reversal model”). The model is based on the coupling system(simulation) mode which is established on “the interactive and parameter-shared water resources system, economic and social system and ecological system” and constrained by “established sustaining ecosystem benign cycle control equations or index threshold”. The mode, regarding “the biggest economic and social support scale supported by large complex system” as the optimized objective function, is the optimizing model of the large scale system. In this model, the input and output relationship sub-model between meteorological factors such as temperature, precipitation and land surface water resources system(river flow) is embedded in order to calculate the dynamic carrying capacity of water resources system in the form of real-time qualification.Taking the basin of Tarim River, China’s largest inland river, as a typical example, the paper, based on the scientific cognition of the characteristics of river basin water resources system,(1)makes an tendency and mutation point analysis of temperature, precipitation and runoff series data;(2) establishes the binary Copula functional equation based on the multivariate probability distribution theory of Copulas function through selecting the main meteorological factors of precipitation, temperature and evaporation together with mountain pass runoff binary copulas, identifies from the perspective of dependency structure the evolution driving forces of river basin water resources system, temperature and precipitation included, reveals the dual influences, the origin areas mainly affected by climate change while the main stream areas by climate change and human activities;(3) analyzes and calculates future dynamic bearing capacity of water resources in different level years in the three climate conditions of RCP8.5, RCP4.5 and RCP2.6 by means of constructing dynamic regression forecasting model of main meteorological factors such as temperature,precipitation and runoff. Calculation results can clearly reflect the water resources carrying scale under the different climate conditions, and can estimate the degree of water resources carrying capacity under the future economic and social development situation and provide the basis for supporting river basin sustainable development;(4) in accordance with the characteristics of water resources of Tarim River Basin and the calculation results of its dynamic carrying capacity under different climate changes and based on the human-water harmony theory, systematically presents the harmonious control strategy of basin water resources and adaptive regulation measures under the changing climate from the aspects of allocation, utilization, scheduling and management, thus providing scientific basis for actively tackling the negative effects of climate change and carrying out the most severe water resource management.