Subjects: Geosciences >> Geography submitted time 2024-05-20 Cooperative journals: 《干旱区地理》
Abstract：黄土高原水蚀风蚀交错区作为中国北方典型的生态脆弱区，因其独特地形和气候条件，极端降雨事件对其环境和生态系统的影响更加突出。选取水蚀风蚀交错区28个气象站点，结合RClimDex模型计算11个极端降水指数，采用线性相关分析法、Mann-Kendall趋势检验法和小波交叉法，分析了1970—2020年黄土高原水蚀风蚀交错区极端降水事件时空分布特征，探讨了极端降水事件的驱动因素。结果表明：（1）1970—2020年水蚀风蚀交错区持续干燥日数（CDD）呈下降趋势，其余10个指数呈上升趋势，反映出近50 a研究区极端降水事件的频率、量级和强度不断增加。交错区年降水量增加和极端降水事件增加具有密切关系，且极端降水事件增加主要是由中雨日数（R10）和大雨日数（R20）引起。（2）1970—2020年极端降水事件在全区整体为增加趋势，交错区中部和西南部极端降水事件显著发生，陕西段极端降水量和强度呈显著增加趋势且极端化程度更显著。（3）湿日总降水量（PRCPTOT）、暴雨日数（R25）、5 d最大降水量（R5d）3个极端降水指数，与影响因子厄尔尼诺-南方涛动（ENSO）、东亚夏季风（EASM）和太阳黑子（SN）具有不同的功率，与SN的交叉小波变换功率最大，说明影响因子中SN和极端降水指数的相关性最高，SN对极端降水事件的影响最大。
Subjects: Geosciences >> Geography submitted time 2024-04-01 Cooperative journals: 《干旱区地理》
Abstract：夜间文旅消费集聚区是推进文旅融合高质量发展的典型示范，对引领文旅产业发展、释放夜间消费潜力具有重要意义。采用GIS空间分析、地理探测器等方法探究中国夜间文旅消费集聚区空间格局及影响机理。结果表明：（1）夜间文旅消费集聚区呈现“东密西疏、南多北少”的集聚型分布态势，“环城、亲水、傍景”布局特征明显，“一主、两副、多微核”的空间形态显著。（2）夜间文旅消费集聚区分布的空间正相关性明显，呈现“东热西冷”圈层式递减的空间分异格局。（3）类型结构上，遗址遗迹类分布在历史文化悠久地区，风土民俗类集聚在少数民族地区，产业主题类空间分布广泛，风景名胜类分布较为均衡，文旅商综合类主要分布在经济发达地区。（4）地形、河流和气候是影响夜间文旅消费集聚区分布的基础要素，人口素质、客运能力、产业发展和政策支持是影响其分布的关键因素。
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The probability distribution function (PDF) of the liftoff velocities of aeolian (wind- blown) sandparticles, an important parameter in sediment transport and dust emission models, remains poorly understood dueto the challenges in tracking particle dynamics during the liftoff process. To reliably describe this distributionfunction, measurements of the individual particle trajectories near the sand- bed during sediment transport arerequired. In this study, we address this issue by employing an improved particle tracking velocimetry technique,enabling us to capture the particle-bed collision process of many liftoff grains in consecutive images and, consequently,to obtain multiple liftoff particle trajectories with different liftoff modes during sand transport in a boundary layerwind tunnel. Subsequently, using the wind tunnel, we measured the trajectory of splash particles, reboundparticles that generated no splash particles, and rebound particles that generated only one splash particle near thesand bed. By analyzing the probability distribution of the liftoff velocities of these three liftoff modes, aprobability distribution model for the liftoff velocities of particles in a steady-state wind-sand flow was constructed.The results indicate the following: (1) The liftoff angles and speeds of the three liftoff modes all follow aLognormal probability distribution. (2) The PDF for the liftoff angle of the total liftoff particles is largelyunaffected by the liftoff mode. (3) The PDF for the liftoff velocity of the total liftoff particles is mainly controlledby the number of splash particles to that of rebound particles. This indicates that the development process of wind-sandflow or turbulence fluctuations impacts the PDF of liftoff velocity. The different shapes of the probabilitydistribution curve for liftoff velocities may only reflect the specific development of wind-sand flow. Our resultsoffer new insights into the aeolian sand saltation process near the bed surface and are crucial for simulatingparticle-bed interactions and improving geomorphic dynamics models in aeolian sand transport. Our study on theprobability distribution model of liftoff velocity opens a new avenue of investigation in the aeolian and soilsciences and aids the understanding of the dynamics of near- bed particle transport. This transport plays anessential role in aeolian research, as well as in the geomorphodynamics of Earth, Mars, and other celestial bodieswithin our solar system.
Subjects: Geosciences >> Geography submitted time 2023-12-06 Cooperative journals: 《干旱区地理》
Abstract：巨型沙波纹条带（Megaripple stripes，MRS）是一种巨型沙波纹在来流方向上呈条带状分布的纵向风成地貌，包括巨型沙波纹尺寸较大的巨型沙波纹走廊（Megaripple corridor，MRC）和尺寸相对较小的微床面形态走廊（Smaller bedform corridor，SBC）。采集柴达木盆地MRS表层沉积物样品共112个，对其物理性质（粒度特征）和化学性质（常量元素和微量元素）进行分析。结果表明：（1） 柴达木盆地MRS表层沉积物中MRC的优势粒级为砾石（44.24%~50.19%）和极细沙（15.91%~20.42%），粒度分布呈双峰型；SBC的优势粒级为极粗沙（26.00%~35.90%）和细沙（14.80%~20.47%），粒度分布呈三峰型。（2） MRS分选很差，偏度以正偏为主，峰态为宽到很宽。（3） MRC和SBC各元素含量差异不大。常量元素以SiO2和Al2O3为主，含量分别在63%和10%左右；微量元素以Cr、Co、Mo和Ba为主。除Cr和Mo外其余元素均为迁移淋失的状态。（4） 柴达木盆地MRS为寒冷干燥环境下的低等化学风化，处于大陆风化初期，化学风化侵蚀相对稳定。
Subjects: Geosciences >> Geography submitted time 2023-11-13 Cooperative journals: 《干旱区地理》
Abstract：预测并分析老年人公园绿地资源可获取性对提高老年人生活品质、有效应对我国老龄化社会带来的有关挑战具有重要意义。为使城市公园绿地的分布更具适老性，基于西宁市带有年龄标识信息的手机位置数据，识别并预测老年人口的空间分布，运用高斯两步移动搜索法对老年人公园绿地可达性进行研究及预测。结果表明：（1） 20182028年老年人数显著增加，且老年人数变化量呈现中心城区及远郊区较低、近郊区高的环状分布特征。（2） 10 a间，老年人公园绿地可达性的空间分布总体格局未发生显著变化，但可达性水平总体下降。（3） 20182028年老年人公园绿地可达性相对变化量较大，步行和公交30 min条件下，约87%的空间单元的公园绿地可达性降低超过70%。研究结果补充了高空间精度下城市老年人公园绿地可达性研究的不足，提供了面向老龄化发展需求的城市未来公园绿地规划建议。
Subjects: Geosciences >> Geography submitted time 2023-09-19 Cooperative journals: 《干旱区地理》
Abstract： In the contexts of the national strategies for ecological protection and high-quality development in theYellow River Basin, as well as of the new era of development in western China, it is necessary to alter the ecological conditions and resource endowment of the“three water-related lines”area in northwest China (an area occupying two distinct basins of the Yellow River and the inland rivers) and to innovate a framework and paradigmsfor coordinated ecological-economic development specific to the area. Based on existing ecological-economicstheories, as well as on the developing philosophy of“a benign environment equal to wealth”and the concept ofthe“human-nature community”, we propose a conceptual ecological-economic framework for the“three waterrelated lines”area, in which we identify the interactions between subsystems and their mechanisms and suggestfour paradigms and four eco-economic hub areas. Further, we propose a layout for modern agriculture and indicate the pathway to coordinated urban and rural development in the four suggested eco-economic hub areas. Weconclude that the proposed“three water-related lines”ecological-economic framework represents a theoreticalfoundation on which to base decisions concerning the layout of socio-economic development and ecological-environmental protection, the construction of ecological-economic hubs, and the overall harmonious ecological-economic development of northwest China.
Subjects: Geosciences >> Geography submitted time 2023-06-28 Cooperative journals: 《干旱区地理》
Abstract：黄河流域城市群绿色发展对于全流域生态保护与绿色高质量发展至关重要。采用超效率SBM模型测度黄河流域七大城市群所辖城市20072019年的绿色发展效率，对其时空演化特征进行刻画，并分别采用引力模型和均衡函数分析七大城市群间绿色发展的关联特征和城市群内部的均衡特征。结果表明：（1）从时序特征来看，城市群的绿色发展效率以2014年为界呈现先下降后上升的变化趋势。（2）从空间分布来看，城市群所辖城市的绿色发展效率在空间格局上呈现低效率空间集聚现象。（3）从关联特征来看，不同城市群间绿色发展的关联强度存在较大差异，其关联关系主要有单向溢出关联、双向溢出关联和无关联。（4）从均衡特征来看，城市群的绿色发展效率与其均衡度之间存在负相关关系，且各城市群在绿色发展效率和均衡度的关系上主要呈现低效率-高均衡度、低效率-低均衡度和高效率-低均衡度3种类型。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-04-07 Cooperative journals: 《干旱区地理》
Abstract： Flash drought is a type of drought characterized by rapid intensification. In the context of global warming, flash droughts are increasingly frequent, which has had a devastating impact on the agricultural ecosystem and public health of China. Understanding the spatiotemporal variation characteristics and influencing factors of flash drought events is of critical importance for monitoring, early warning, and loss prevention. On the basis of ERA5- Land data from 1981 to 2020, this study examined the spatiotemporal variation of two types of flash drought (heat wave and precipitation deficit flash drought) in the Loess Plateau using trend and correlation analyses. The relationship between the different atmosphere-ocean oscillation indices and the number of flash drought is also examined. The following results are presented. (1) The frequency of the two types of flash drought increased significantly from 1981 to 2020, with a higher increasing precipitation deficit rate [0.54 penta·(10a) − 1 ] than that of heat wave [0.46 penta·(10a)−1 ] flash drought. Particularly, the two types of flash drought had a similar pattern in decadal variation. Before 1998, the two types of flash drought primarily displayed low fluctuation. From 1998 to 2010, the number of flash droughts rapidly increased. The growth rate of flash droughts stalled and began to decline after 2010. (2) A spatially significant (P<0.05) upward trend for heat wave (precipitation deficit) flash drought was observed in 36.5% (37.5% ) of the Loess Plateau. The parts of the Loess Plateau with gullies and hills, as well as the eastern Hetao Plain and the Fenwei River Valley Plain, had a marked increase in the incidence of heat waves and precipitation deficit flash droughts. (3) Considering the influencing factors, the trend and interannual oscillations of flash drought in the Loess Plateau can be explained by the sea surface temperature (SST) anomaly in the NINO B region and the atmospheric pressure anomaly in the northern Qinghai-Tibet Plateau. The Loess Plateau had an increase in the probability of flash drought due to positive air pressure anomalies in the northern Qinghai-Tibet Plateau and large SST anomalies in the central equatorial India Ocean.
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 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： The ecological environment quality (based on the principles of space-time, ecology, integrity, and the dynamic changes) and water conservation in Fenhe River Basin in the past 20 years were analyzed by using the RSEI model and the InVEST model. The relationship between RSEI and water conservation was studied through the correlation analysis. The results showed that: (1) from 2000 to 2020, the area of a good grade RSEI increased by 23.6%, and the area of excellent grade (mainly distributed in the West and East of Fenhe River Basin) increased by 1.9% (2) In 2020, the total amount of water conservation would be 228.9 × 108 mm (an increase of 23 × 108 mm compared with 2000). High conservation capacity was mostly found in the upstream water supply, while the intermediate region of the middle and lower reaches had poor water conservation ability (3) The positive correlation between RSEI and water conservation was 78.42% . Conclusions: (1) The ecological environment of the Fenhe River Basin has been improving continuously for the past 20 years. The medium level shown a declining tendency after fluctuation, whereas the good and poor areas had both increased annually. (2) Over the past 20 years, the water conservation function of the Fenhe River Basin had been continuously improved. The water conservation capacity of the upstream water source areas had increased significantly, while the intermediate and lower reaches had less water conservation capacity. (3) The proportion of positive correlation between the ecological environment and water conservation in the Fenhe River Basin was the largest. The improvement of water conservation capacity could promote the improvement of ecological environment quality and vice versa. There are 21.58% of the regions with negative correlation, which was mainly related to the dominant factors of the two.
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2022-09-26 Cooperative journals: 《干旱区研究》
Abstract： Typical urban rivers in Xi’an (Ba River, Chan River, Feng River, and Hei River) were selected as the research object to understand the impact of different land-use types on the distribution of heavy metals in river sediments. The spatial distribution, environmental risks, and sources of heavy metals (Cr, Mn, Ni, Cu, Zn, Cd, and As) in river sediments were analyzed and evaluated using potential ecological risk (RI), pollution load index (PLI), correlation analysis, and principal component analysis. Results showed that the content of heavy metals in the sediments of the four rivers was presented in the following order: Chan River > Ba River > Hei River > Feng River. The RI results showed that Cd remarkably contributed to the pollution, and the four rivers were all at moderate potential ecological risk. The PLI results showed that the H1 sample site in Hei River was moderately polluted, which was the highest. The RI and PLI results showed that the sample sites in the Chan River were the most polluted, and they were concentrated in the middle and lower reaches where the proportion of artificial ground and intensity of human activities were high. In addition, the results of correlation analysis and principal component analysis showed that most heavy metals came from human activities such as emissions from industrial and agricultural production and traffic pollution. Therefore, attention should be paid to the prevention and control of Cd pollution, particularly in the middle reaches of Feng River and Hei River, to prevent further pollution.
Subjects: Geosciences >> Geography submitted time 2022-08-09 Cooperative journals: 《干旱区地理》
Abstract：旅游地感知是旅游地理学重要的研究领域之一，一带一路倡议背景下，游客空间感知与地方想象研究对推动边疆生态旅游地品牌化建设，促进边疆去边缘化和旅游发展具有重要的理论和现实意义。以额济纳绿洲为例，综合集成内容分析法、社会网络分析法、文本分析法与社会访谈法，探讨了边疆生态旅游地游客空间感知意象特征与地方想象建构过程。结果表明：（1）绿洲景观生态与自然风貌是生态旅游地空间感知中最主要的部分，其中，胡杨林在游客空间感知意象网 络中居于核心位置，胡杨符号成为游客审美和消费偏好。（2）K-核分析发现，胡杨要素贯穿所有凝聚子群层次变化过程，胡杨景观及其延伸的社会文化意义是游客重点关注的内容。随着K-核级数增加，游客由着重关注绿洲胡杨森林景观向绿洲森林、地貌、水体等综合自然景观过渡，绿洲人文景观除黑城遗址和策克口岸外，其他较少受到游客青睐。（3）基于边疆独特的景观符号、典型的地域符号和层累的文化符号，借助真实空间的具身体验和想象空间的文化建构，游客对额济纳绿洲展开丰富的生命想象、边塞想象与秘境想象，塑造出绿洲鲜明的地方意象。
Subjects: Geosciences >> Geography submitted time 2022-08-09 Cooperative journals: 《干旱区地理》
Abstract：主要运用历史文献分析法和GIS空间分析法，总结宁夏地区汉代丝绸之路沿线98个村落遗址空间分布特征。结果表明：该区域村落遗址空间上已呈现1个集聚中心和4个次集聚中心，且在今固原市辖域内形成一处西北东南空间集聚分布区。古遗址具有较为明显的濒水特征，距水源1 km以内者占总数的54.08%，且多集中于坡度2~6的丘陵、台地阳坡上。为更加准确地探求自然环境和人文社会各影响因子对研究区域内村落遗址空间格局的影响作用，故引入地理探测器予以分析。可知除以水源为典型代表的自然环境等要素制约村落的形成与发展外，中心聚落和交通区位共同构成主要影响因素，前者更是主导因素。至迟于汉代，已出现人文社会诸要素对村落选址分布的决定程度远超自然环境各要素这一变化趋势。
Subjects: Geosciences >> Geography submitted time 2022-08-09 Cooperative journals: 《干旱区地理》
Abstract：城市高速发展引起了区域土地利用格局的改变，不仅影响生态环境质量，而且还对生态系统服务的空间格局产生影响，在此基础上优化生态系统服务显得至关重要。在泾河流域20002020年净初级生产力（Net primary productivity, NPP）、农业生产力、土壤保持和产水服务空间评估的基础上，将贝叶斯网络和生态系统服务相结合，在关键变量子集和可视化的最优状态子集的基础上，评估了4种生态系统服务需要优化的区域，为区域经济和生态和谐发展提供参考。结果表明：（1）水文评价模型（Soil and water assessment tool, SWAT）模型能较准确地模拟区域的径流量。通过模拟值和观测值对比分析，该模型具有较高的决定性系数（R2>0.6）和纳什效率系数（NSE>0.5），可为进一步评估产水服务提供保障。（2）20002020年泾河流域4种生态系统服务的时空差异性较为显著。在时间尺度上，4种生态系统服务均呈现波动中上升的趋势，在空间尺度上呈现较为稳定的变化趋势。（3）通过对4种生态系统服务优化区域进行叠加分析，发现综合优化区域集中在彭阳县的中部和西南部以及环县的零星区域。研究结果对指导优化区域进行生态系统的可持续管理以及改善生态系统的退化状况具有重要意义。
Subjects: Geosciences >> Geography submitted time 2022-04-16 Cooperative journals: 《干旱区地理》
Abstract：村庄是最能直接体现乡村经济社会活动规律的单元，落实到村级层面的功能类型划分是分类推进乡村振兴的关键。以行政村为基本单元，采用熵权法、泰尔指数及优势功能模型，构建适用于村庄发展功能识别与类型划分的研究思路，并以西北干旱绿洲农业区临泽县为例进行实证研究。结果表明：干旱绿洲农业区总体形成以农产品生产和生态保育为主的国土空间格局，村庄形成农业种植、畜牧养殖、工业加工、商贸旅游、劳务输出、生活保障等多功能地域综合体，其中农品生产和生活保障功能总体空间差异较小，而非农生产功能空间差异较大。村庄因资源禀赋、规划引导、政策驱动和社会需求差异形成不同的优势功能类型，空间上呈现外围生态、沿河种植、中部农牧、临城劳务，文旅、商旅、生活保障以政府驻地及附近村庄为主的分布规律，并形成非农生产功能镶嵌于农业生产功能之中、生产生活功能被生态保育功能包围的分布格局。通过自上而下 主体功能统筹与自下而上经济社会需求相结合的方法进行村庄发展功能识别和类型划分具有较强的适用性和实践指导价值，在巩固国家主体功能定位、保障国家粮食和生态安全的同时，可以调整优化县域资源要素配置，实现村庄发展功能互补与功能协调。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2022-01-21 Cooperative journals: 《干旱区地理》
Abstract：采用随机重排去趋势波动分析（MF-DFA）和极点对称模态分解法（ESMD），对19552019年西安市昼夜复合高温事件变化特征进行分析。结果表明：（1）气象站点迁移，造成对西安市极端高温变化趋势低估。其中，最高温原始数据与订正序列阈值相同；订正后，最低温阈值相对偏低0.2~0.5 ℃。（2）MF-DFA、90.0%和95.0%阈值方案识别高温事件年代变化具有相似性，而99.0%阈值和相对阈值方案是结论不确定性的主要来源。（3）在变化特征上，西安市昼夜复合高温事件兼顾3.3~3.8 a年际波动和趋势变化，20世纪80年代中期，昼夜复合高温天数呈现显著增多。（4）赤道西太平洋海温异常，可作为西安市昼夜复合高温预警的关键海区。即赤道西太平洋海温异常偏高时，往往对应西安市昼夜复合高温多发期，并指出南亚高压偏北、西太平洋副热带高压西伸，是影响西安市持续昼夜复合高温的环流机制。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-12-14 Cooperative journals: 《干旱区地理》
Abstract： 帕米尔高原是中亚最重要的水源地，但因其较高的海拔导致降水数据极其缺乏，限制了对 帕米尔高原大气降水和水文过程的认识。为认知帕米尔高原降水的空间分布，使用 WRF（Weather research and forecasting）模式，以 6 km 的高分辨率模拟了 2016 年 12 月至 2017 年 11 月帕米尔高原大气降水的时空分布，模拟结果揭示了帕米尔高原高大地形对水汽输送的阻滞作用，造成帕米尔高原各季节降水主要分布在迎风坡上。在冬季和春季，降水主要发生在帕米尔高原西侧迎风坡，降 水整体上随海拔的升高而增大，降水区集中在海拔3000~5000 m 处，高海拔地区降水量高出平原地区数倍之多。而夏季降水主要出现在帕米尔高原的南麓，因高原的阻挡，夏季风不能深入到高原 内陆，造成夏季高原顶部降水量不足 100 mm。
Subjects: Geosciences >> Geography submitted time 2021-10-10 Cooperative journals: 《干旱区地理》
Abstract： 维持城市生态系统服务供需平衡是建设宜居城市、提高城市居民福祉的基础，同时对区域 经济与可持续发展具有重要意义。以西安市建成区为例，基于 2018 年遥感数据、统计数据和实地 调研等多源数据，构建粮食需求、水资源需求、固碳释氧、空气净化、高温调节、减弱噪声和休闲娱 乐服务需求测算模型，并应用 ArcGIS 等分析工具，对研究区城市绿色基础设施（Urban green infra⁃ structure，UGI）服务供需空间匹配关系进行评估和分析，最后运用最小累积阻力模型识别生态源地 和生态廊道，对西安市 UGI 空间格局进行优化。结果表明：（1）西安市建成区 UGI 分布不均匀，破 碎化程度高，连通性较差。UGI 提供的生态系统服务总价值小于居民对服务需求总价值，在空间上 表现为显著不匹配性。（2）不同生态系统服务供需匹配状况存在差异，高温调节服务、空气净化服 务和休闲娱乐服务供大于求，匹配状况较好；粮食供给、固碳释氧、水源涵养和减弱噪声服务供小 于求，供需赤字。（3）研究区生态系统服务供需具有显著空间异质性，随着人口集聚程度的提高，大 部分生态系统服务（如高温调节、减弱噪声等）供需的空间匹配程度显著下降，在空间上表现为由 城市中心的严重失调向边缘的良好匹配渐变。（4）研究区生态源地斑块面积较小，破碎化程度高， 连接度低，UGI 网络缺乏主干生态廊道。通过构建由沿渭河、秦岭北麓 2 个生态走廊，沣河、潏河、 灞河等 7 个生态保育区及沿道路绿化带等组成的 UGI 网络，可使生态系统服务供需空间关系更趋 协调。
Subjects: Geosciences >> Geography submitted time 2021-10-10 Cooperative journals: 《干旱区地理》
Abstract： 绿洲是干旱内陆区的精华部分，也是生态文明建设的难点地区，加强绿洲生态治理研究对 推进区域生态文明建设具有重要的理论和现实意义。长期以来，绿洲生态治理研究强调通过技术 手段、经济措施促进绿洲生态系统恢复，对行动主体在生态治理中的作用重视不够，影响了绿洲生 态治理成效和可持续性。以额济纳绿洲为案例，在深入调研基础上，援引空间生产理论和区域治 理理论，通过政策工具组合分析，探究纵向嵌入治理下绿洲生态空间生产过程。结果表明：（1）中 央政府的机构嵌入打破了传统“以粮为纲”的水资源配置导向，流域用水制度从“粮食生产偏好”向 “生态保护偏好”转变，绿洲被建构为国家生态保育空间，成为中国北疆重要的生态安全屏障。（2） 中央政府的行政嵌入重塑了流域用水关系和水权秩序，促成了黑河干流水量调度，实现了绿洲来 水增多化，干涸多年的东居延海出现稳定水面被开辟为生态旅游景区，由戈壁沙漠湖泊湿地转变 为生态观光旅游胜地，重构了黑河尾闾生态空间。（3）中央政府的规则嵌入解决了绿洲工程建设中 资金短缺问题，通过对绿洲灌溉的人工化控制和绿洲生态保护区化治理，实现了绿洲河网渠系化 与绿洲空间功能化，绿洲由边境牧业生产生活空间转变为国家重点生态功能空间。
Subjects: Geosciences >> Geology submitted time 2021-10-10 Cooperative journals: 《干旱区地理》
Abstract： 受气候振荡的影响，沙漠边界多次往复摆动，在地层中留下了黄土、古土壤与古风成沙的迭 覆沉积。通过传统粒度参数和端元分析模型方法对陕西横山 HS 剖面 L2 以来风成沙—沙质黄土— 沙质古土壤所蕴含的粒度成分、相应的沉积信息和沙地进退进行探讨。结果表明：HS 剖面粒度组 成不同于黄土区，以极细砂（31.07%）、细砂（30.20%）和粗粉砂（23.38%）为主，具有大小混杂的宽粒 级范围的明显特征。因此在黄土区具有全球古环境意义的粒度指标未必适合本区，运用参数化端 元分析模型对本区粒度指标进行分离，以期得到适宜本区的气候环境指标。其中，端元 1（EM1）的 众数粒径为 8.93 μm，反映了西风环流的信息；端元 2（EM2）的平均粒径为 32.82 μm，很大程度上间 接指示东亚冬季风强度的变化；端元 5（EM5）的平均粒径为 235.46 μm，是极强冬季风或强风暴的 替代性指标，其含量反馈当时冬季风的强烈程度。由此，研究认为陕西横山自 L2 以来发生了 5 次沙 地扩张和 3 次沙地后退事件，其中风成沙层为强烈冬季风环境引发毛乌素沙地扩张时堆积的；而冬 季风强度大为减弱时，沙丘迁移被沙尘堆积所取代，形成沙质黄土层；古土壤层是在冬季风相对萎 缩时发育的。冰期形成的风成沙层对目前区域沙漠化存在不可忽视的潜在威胁，保护全新世形成 的土壤层是防治区域沙漠化的重要措施。
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