Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： In the context of new urbanization development, the coordinated development of economy and ecology in Gonghe County, Qinghai Province, which is a key node in the construction of the Lanxi urban agglomeration and a typical desert area that is ecologically fragile. It is of great significance to China in accelerating the construction a new development pattern and the implementation of the Innovation Demonstration Zone of Sustainable Development Agenda in Hainan Prefecture . Based on the land use data of 2000, 2010 and 2020, this study utilizes the InVEST model to explore the spatial and temporal distribution and effect change characteristics of habitat quality in Republican County from 2000 to 2020, and further investigate the influencing factors and their effects on habitat quality using geographic probes and geographical weighted regression (GWR). The results show that: (1) The overall habitat quality in Republican County from 2000 to 2020 showed an upward trend, and the mean values of habitat quality were 0.612, 0.626, and 0.627, respectively, and there were obvious regional differences in the spatial distribution of habitat quality, and the spatial pattern showed a trend of high in the north and low in the south. (2) The main driving factors affecting habitat quality in Gonghe County were the mean annual temperature (TEM) and normalized vegetation index (NDVI), and the interaction between the factors has a greater influence on the spatial differentiation of habitat quality than a single factor, with TEM interacting strongly with Shannon's evenness index (SHEI) and Shannon's diversity index (SHDI). (3) The GWR model quantified the different driving characteristics and strengths of each driver on habitat quality at the spatial level, with TEM having a negative effect on habitat quality, with the negative effect mainly concentrated in the northern and eastern parts of the republic. The positive effect of gross domestic product (GDP) on habitat quality increased by 30% compared to 2000, and the photovoltaic in Tala Shoal promoted the synergistic development of eco-industry in Gonghe County. The results of the study can provide a scientific basis for decision-making to promote local economic construction and ecological protection in arid areas.The results of the study can provide scientific decision-making basis for promoting local economic construction and ecological environmental protection in arid areas.
Subjects: Biology >> Botany submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： Forest biomass is the basis for studying forest primary productivity, and its carbon density is a crucial indicator for evaluating the structure and function of forest ecosystem. To study changes in the stand density of Qinghai spruce with altitude in Amidongsoe small watershed on the southern slope of Qilian Mountains, a biomass model was used to calculate the carbon density of arbor and soil layers along an altitude gradient of 2900-3200 m at different altitudes. The aim of this study was to gather basic data for estimating carbon storage in spruce forests in the Qilian Mountains and Qinghai Province. The results demonstrated that the average value of total biomass in the study area was 135.59 t·hm−2 and the total biomass decreased as the altitude increased. The average carbon density of tree layer was 70.51 t·hm−2, and the average organic carbon density of the 0-50 cm soil layer was 154.01 t ·hm− 2. As the altitude increased, the carbon density of the tree layer exhibited a decreasing trend, and the soil organic carbon density of the tree layer initially decreased and then increased. At different elevations, the carbon density of spruce forest ecosystem was 224.51 t·hm− 2, with the carbon density of the tree and soil layers accounting for 30.5% and 69.5% of the total carbon density, respectively. The layers showed a decreasing trend as the altitude increased. Protecting forest soil is crucial for maintaining ecological balance, as the forest soil carbon pool represents a considerable proportion of the total carbon density.
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 2022-03-28 Cooperative journals: 《干旱区研究》
Abstract：土壤湿度作为生态环境的关键因子，是土壤监测和生态环境变化的重要指标。本研究基于MOD11A2LST和MOD13A2 NDVI数据，通过温度干旱植被指数TVDI（Temperature Vegetation Dryness Index）、相关性分析和区域统计分析等数理统计分析方法对香日德-柴达木河流域植被生长季的土壤湿度时空分布特征及其影响因素进行分析。结果表明：（1）香日德-柴达木河流域2005年、2010年、2015年和2020年植被生长季TVDI平均值为0.61，最大值为2015年（0.64），最小值为2020年（0.58），年际TVDI值缓慢下降，但在2015年出现上升现象，研究区旱情不稳定且长期处于干旱等级。（2）不同等级土壤湿度的面积从大到小依次为干旱>极干旱>正常>湿润>极湿润，分别占研究区总面积的30.63%、25.77%、22.16%、16.44%、5.01%。（3）TVDI在空间分布上呈现出由西北向东南逐渐递减的趋势，具有明显的区域差异性。（4）TVDI值与海拔呈负相关关系，海拔每升高500 m，TVDI值减少0.11，TVDI值与平均气温呈正相关关系，与坡度和降水量之间不存在明显的相关性关系。
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2021-03-02 Cooperative journals: 《干旱区研究》
Abstract：地表温度是区域气候、农业生产及土壤养分的重要影响因素，分析地表温度的变化规律对深入了解气候变化的原因及农业生产的布局具有重要意义。基于青海省35个气象基站1980—2017年逐日地表温度、气温和风速数据，采用线性趋势分析、Mann-Kendall非参数检验、小波分析等数理统计方法对青海省地表温度的时空变化特征及其与气温、风速、海拔等因子的关系进行了研究。结果表明：（1）青海省年均地表温度呈波动上升的趋势，增温速率达0.68 ℃·(10a)-1（P＜0.01），2001年发生突变；地表温度变化存在明显的季节差异，冬季地温变化速率最明显，为0.77 ℃·(10a)-1（P＜0.01），其他季节差异不大；青海省年均地表温度具有4~7 a和11~16 a两种周期变化；（2）全年地表平均温度分别在青南高原和祁连山区形成2个低温区，在柴达木盆地和东部农业区形成2个高温区，且低温区的增温速率较大；（3）全年及各季地表平均温度与平均气温呈显著正相关，与风速、海拔呈显著负相关关系；（4）地表平均温度呈现出明显的垂直递减规律且海拔高的地区变暖趋势更加明显。
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。
Hits
Hits
Downloads
Comment