| The analysis of hydrometeorological elements has always been a major issue in natural sciences.However,how to implement hydrometeorological research into land resource assessment,optimal use of water resources,and future hydrological pattern prediction is a practical and critical scientific issue.Ninety percent of southern Xinjiang is covered with desert or high mountain uninhabited area,and the remaining10%of the area is residential area due to the existence of rivers and oasis.How to realize the sustainable development of the southern Xinjiang watershed and oasis under the premise of ensuring local ecological security is one of the most urgent problems to be explored in the hydrometeorological element analysis studies.In this context,this article starts with the analysis of hydrometeorological elements,taking the Hetian River Basin as the research area.Carry out regional hydrometeorological element analysis,and conduct change process analysis and periodic analysis of hydrometeorological elements and processes in the basin.After that,the amount of land resources in the oasis in the basin is divided,and the ecological land and agricultural production land are separated and quantified,so as to obtain the local water and land resource utilization pattern to determine the degree of matching and balance between the local water and land resource carrying capacity and utilization.Finally,predict the runoff of the Hetian River Basin under the future climate model,and give an optimized irrigation model.The main research conclusions of this paper are as follows:(1)From 1962 to 2013,the runoff,temperature and precipitation in the Hotan River Basin all showed an upward trend;the sand content fluctuated,while the evaporation showed a linear decrease.Among them,the rate of change of runoff is about 0.27 m~3/s·a.The rate of change of precipitation is 1.01mm/a,and it has been reduced and increased many times in the 1960s.The temperature change rate is about0.05?/a.The sand content change rate of Hetian River showed different trends under different hydrological stations,and the change rates were 0.03 kg/m~3·a and-0.02 kg/m~3·a,respectively.The rate of change of evaporation in the Hotan River Basin is about 25 mm/a.It shows that the temperature rises and the Kunlun Mountain glaciers are melting and increasing,which intensifies the river runoff.At the same time,the increase in temperature causes the actual evapotranspiration to increase,but the regional air humidity increases,which reduces the evaporation of the evaporating pan.(2)From 1962 to 2013,the cycle characteristics of each hydrometeorological element in the Hotan River basin varied.The runoff has mainly varied cycles of 5-10a and 10-15a.Sand content varies in strength of periodicity on different time scales,with stronger variations on 3-5a and 6-10a time scales.The periodicity of precipitation and temperature is mainly distributed in the 5-10a time scale.The periodicity of evapotranspiration is mainly concentrated in the 12-16a time scale.The wavelet coherence of runoff and sand content has a significant period of 0-6a and belongs to positive correlation during this period.The wavelet coherence between runoff and precipitation has a significant period of 0-7a and is negatively correlated in this period.The wavelet coherence between runoff and air temperature has a significant period of 0-6a,mainly from the mid-1980s to the mid-1990s,and is positively correlated,but the change in air temperature is faster than the change in runoff.The wavelet coherence of runoff and sand content has a significant period of 0-5a,but the distribution time is intermittent,and the flow and sand content have positive correlation in this period.(3)The SWAT model model has good utility in the Hotan River basin.Although the hydrological observations are missing in the time series,the model has NS of 0.500 and R2 of 0.699 in the calibration period(1956-1984)and NS and R~2of 0.641 and 0.721,respectively,in the validation period(1985-2013).the Wada River under the actual climate scenario,r2.6?r4.6?and r8.5 for three future climate models The runoff volumes during the dry water period are 37.13×10~8m~3,42.76×10~8m~3,43.40×10~8m~3,44.53×10~8m~3;during the flat water period are 43.4×10~8m~3,48.52×10~8m~3,49.07×10~8m~3,50.6×10~8m~3;during the rich water period are 50.36×10~8m~3,55.52×10~8m~3,56.24×10~8m~3,58.37×10~8m~3.The proportion of water delivery to ensure downstream ecological security in flat,abundant and dry water years is 23.80%,29.80%and18.20%,respectively.For Hotan Oasis,agricultural irrigation water is the item with the largest proportion of local water resources use,with 43.71%.The suitable arable land area of Hotan Oasis is 3,498,700 mu after double evaluation and assessment based on this,which is slightly smaller than the actual arable land area within Hotan Oasis(3,652,500 mu);thus,it can be seen that there is a certain degree of mismatch in water and soil resource utilization in Hotan Oasis area.By simulating the irrigation water storage in the Hotan Oasis irrigation area under different irrigation methods,it is found that the above-mentioned mismatch in water and soil resource utilization can be solved to a certain extent by reducing the area of diffuse irrigated land and vigorously promoting sprinkler and drip irrigation technologies. |
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