Variation Characteristics Assessment For Water Resources The Hotan River Basin In Xinjiang Under Climate Change

At the background of global extreme climate change,we can not ignore its huge impact on water resources,eco-environment and social development.However,the regional climate characteristic of scarce precipitation and strong evaporation challenges the management of water resources.Therefore,it's necessary to carry out the water resource management concept of“depending on water and measuring water”.In this paper,Hotan River Basin(HRB)is taken as the study area,HRB is a typical inland river basin in northwest China.The temporal and spatial characteristics of snow cover in the basin are analyzed.The applicability of snowmelt runoff model(SRM,snowmelt runoff model)in alpine area is verified,and studied the impact of climate change on snowmelt runoff.At the same time,based on the water and heat balance model,the multi scenario analysis of the scale of Hotan oasis,which is the key dissipative area of water resources in the basin,will provide direction for the future regional water resource management and green development.(1)Based on the National Meteorological Information Center(Hotan station)and China Meteorological Forcing Dataset(CMFD),this paper analyzed the air temperature and precipitation in HRB.The results show that from 1959 to 2018,precipitation and temperature showed an upward trend,and the temperature changed abruptly in 1999.From the periodic analysis,the main periods of precipitation and temperature are 24a and 28a,respectively.Hurst analysis shows that"warming+wetting"is the dominant direction of future climate change.Compared with Hotan station,CMFD data shows that the trend of temperature and precipitation is similar,and the overall estimation is relatively high.(2)Based on the MOD10A2 data from January 2004 to March 2018,the temporal and spatial changes of snow cover in HRB were analyzed.The results show that the snow cover fraction changes in different elevation zones are different.The altitude is 3500?5000m,which is represented by the secondary ablation process of the"W"curve.The snow cover in different elevation zones has a negative correlation with air temperature,wind speed and sunshine.The spatial distribution of snow change shows that,the high frequency of snow is in the northern foothills of Kunlun Mountain,showing a"northwest-southeast"band distribution.For many years,the average snow height has been on an upward trend,with a propensity rate of 147.32 m/10a.(3)This study constructed the SRM(Snowmelt Runoff Model)of the HRB to simulate snowmelt runoff under the different future climate change scenario.The results show that R~2and Dv is 0.93 and 11.01%,respectively.and the simulated annual average flow rate is53.03×10~8m~3,indicating that SRM has certain applicability in the HRB.Snowmelt runoff response studies have found that runoff is positively and negatively correlated with air temperature and snow line,respectively.Increased temperature will increase snowmelt runoff,and temperature will have a greater impact on runoff than snow line.When keeping the future snow line rising and the temperature rising by 1.5?and 2.0?,the thresholds of snowmelt runoff increase are 34.71%and 49.23%,respectively.(4)The water-heat balance model of Hotan Oasis was constructed to study the characteristics and scale of water resources dissipation in the oasis area of the HRB.The results show that the driving factors of water resources are mainly human activities,comprehensive climate change components and climate tendency components.Water consumption is mainly related to the increase in water consumption for agricultural irrigation and the intense evaporation of reservoirs and lakes.The current annual oasis scale is 3683.67km~2.In 2030,the appropriate oasis scale is 3183.26?3739.92 km~2,and the threshold of suitable cultivated land area is 1149.97 km~2.In the"standard scenario(S3)",the oasis area is 3528.30 km~2,which is overloaded.Under the"Vision Model(S2)",the oasis scale in 2030 is3739.92 km~2.To realize the green development of oasis,the eco-environmental safety network for constructing"one corridor,two screens and three belts"and related countermeasures for the restoration and protection of oasis water ecology are proposed.