Subjects: Geosciences >> Hydrology submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： Water shortage has become a major resource and environmental challenge worldwide. Climate and land use change have made the evolution of current hydrological factors complex and uncertain. Exploring the spatial distribution characteristics of hydrological factors under dynamic scenarios is of vital theoretical and practical significance for the sustainable development of regional economy and society. The meteorological and hydrological data of the Datong River source region from 1960 to 2019 were used in this study to quantitatively analyze the spatial distribution characteristics of hydrological elements under climate and land use change scenarios based on model simulation and scenario segmentation. The results showed that: (1) After calibration and verification of the SWAT model, the coefficient of determination, Nash coefficient, and percentage bias (PBIAS) all met the model requirements of 0.81%, 0.79%, and −0.8% in the rate period, and 0.81%, 0.75%, and 15.8% in the validation period, respectively, which indicated that the model had good applicability in the headwaters of the Chase River. (2) Obvious spatial heterogeneity of hydrological elements was detected in the headwater area of Datong River, and a single hydrological element could not represent the overall spatial distribution. Precipitation, potential evapotranspiration, and soil water content decreased with the increase in altitude, while surface runoff and water yield increased with the increase in altitude. (3) The spatial distribution of hydrological factors under the three scenarios were generally consistent, while the spatial distribution of water yield was greatly affected by the land use change. Under the climate change scenario, the actual evapotranspiration and soil water content showed a downward trend, while the surface runoff and water yield showed an upward trend. Under the land use change scenario, the changes of hydrological elements were contrary to these observations.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： Evapotranspiration (ET) is the total flux of water vapor transported by vegetation and the ground as a whole to the atmosphere. As an important part of energy balance and water cycle, ET affects the growth and development of plants and regulates climate by influencing atmospheric circulation. Using MODIS image data combined with digital elevation model data and meteorological data, this work applied ArcGIS spatial analysis and mathematical statistics to study the temporal and spatial characteristics of ET in the Shaliu River Basin of Qinghai Lake in the past 20 years from 2000 to 2019. The correlation between ET and meteorological factors such as air temperature, precipitation, and relative humidity and its topographic effect was also explored. Results show that: (1) the annual average ET in the Shaliu River Basin of Qinghai Lake is between 379.7 and 575.4 mm, and the average ET is 501.9 mm. The overall trend of fluctuation increases significantly with the number of years (P<0.05), and the linear slope is 5.9 mm·a-1. (2) From a spatial perspective, the average ET in the Shaliu River Basin of Qinghai Lake has significant spatial differences and shows a distribution pattern of“high in the middle and low at both ends,”that is, the ET in the source area and the downstream estuary delta area is lower than that in the middle reaches. The order is as follows: alpine meadow belt > alpine cold desert belt > alpine grassland belt. The areas with a relatively significant increase in ET are mainly distributed in the estuary delta area in the lower reaches of the basin, accounting for 9.7% of the basin area. Meanwhile, the areas with a relatively slight increase occupy the main body of the basin, accounting for 81.2%. (3) The annual ET is related to the annual average temperature, and the annual precipitation is significantly positively correlated with the annual average relative humidity. Warming is the fundamental driving force for the increase in ET. (4) The annual ET showed an “increase-decrease-increase”trend with the increase in the slope, but the overall difference between the slopes is not evident. Except for the smallest plane ET in different slope aspects, the differences in annual ET among the other slope aspects are small. The annual ET increases sharply at first and then gradually with the altitude. The above results show that in the past 20 years, the warming and humidification of the climate in the Shaliu River Basin of Qinghai Lake has led to an increase in ET. However, the band increase is small.
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：水体氢氧稳定同位素是表征水体运移和水分转化的重要指示剂，可为地区水文循环过程的研究提供判断依据。基于稳定同位素技术，分析祁连山南坡不同水体的氢氧同位素组成特征，探讨其影响因素。结果表明：（1）祁连山南坡不同水体的氢氧稳定同位素特征存在差异，降水的稳定同位素值波动范围大于河水、地下水及冰川融水；（2）河水与地下水稳定同位素关系点接近，两者水力联系较强；（3）研究区冰川融水蒸发线方程为y=6.331x+1.756（n=8，R2=0.98），河水蒸发线方程为y=4.467x-11.716（n=75，R2=0.80），地下水蒸发线方程为y=4.889x-7.481（n=19，R2=0.76），各水体氢氧稳定同位素值之间均具有较好的线性关系，河水与地下水补给源关系较复杂；（4）冰川融水、河水与地下水氢氧稳定同位素的环境效应均不显著，而降水则具有较明显的高程效应、纬度效应和大陆效应。
Subjects: Geosciences >> Hydrology submitted time 2020-06-12 Cooperative journals: 《干旱区地理》
Abstract： 地下水稳定同位素组成的时空变化特征可以反映不同时期、不同区域地下水补给来源的差异。本文研究了青海湖沙柳河流域浅层地下水氢氧稳定同位素组成的时空变化特征以及地下水、河水与降雨之间的补给关系，并得出如下结论：季风时期，地下水主要受降雨入渗和河流侧向补给为主，在补给过程中蒸发作用是影响地下水稳定同位素值的主要因素；非季风期，冰雪融水对低值区的地下水影响显著，同时降水的快速入渗则是该时期高值区地下水的主要补给方式之一。地下水同位素高值区，地下水与河水间补给作用较弱，补给时间超过5个月；地下水同位素低值区，地下水与河水补给关系较为密切，补给时间在1-4月间。本研究所得结论可初步反映干旱半干旱内陆流域地下水稳定同位素特征以及补给方式的基本规律，在一定程度上可为研究流域地下水及其他水体间的转换提供科学依据，并为地下水资源管理和水环境治理提供一定理论指导。
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