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1. chinaXiv:202205.00165 [pdf]

Transport mechanism of eroded sediment particles under freeze-thaw and runoff conditions

Subjects: Geosciences >> Geography

Abstract: Hydraulic erosion associated with seasonal freeze-thaw cycles is one of the most predominant factors, which drives soil stripping and transportation. In this study, indoor simulated meltwater erosion experiments were used to investigate the sorting characteristics and transport mechanism of sediment particles under different freeze-thaw conditions (unfrozen, shallow-thawed, and frozen slopes) and runoff rates (1, 2, and 4 L/min). Results showed that the order of sediment particle contents was silt>sand>clay during erosion process on unfrozen, shallow-thawed, and frozen slopes. Compared with original soils, clay and silt were lost, and sand was deposited. On unfrozen and shallow-thawed slopes, the change of runoff rate had a significant impact on the enrichment of clay, silt, and sand particles. In this study, the sediment particles transported in the form of suspension/saltation were 83.58%–86.54% on unfrozen slopes, 69.24%–84.89% on shallow-thawed slopes, and 83.75%–87.44% on frozen slopes. Moreover, sediment particles smaller than 0.027 mm were preferentially transported. On shallow-thawed slope, relative contribution percentage of suspension/saltation sediment particles gradually increased with the increase in runoff rate, and an opposite trend occurred on unfrozen and frozen slopes. At the same runoff rate, freeze-thaw process had a significant impact on the relative contribution percentage of sediment particle transport via suspension/saltation and rolling during erosion process. The research results provide an improved transport mechanism under freeze-thaw condition for steep loessal slopes.

submitted time 2022-05-25 Cooperative journals:《Journal of Arid Land》 Hits3Downloads0 Comment 0

2. chinaXiv:202205.00166 [pdf]

Wind regimes and associated sand dune types in the hinterland of the Badain Jaran Desert, China

MENG Nan; WANG Nai'ang; ZHAO Liqiang; NIU Zhenmin
Subjects: Geosciences >> Geography

Abstract: Wind controls the formation and development of sand dunes. Therefore, understanding the wind regimes is necessary in sand dune research. In this study, we combined the wind data from 2017 to 2019 at four meteorological stations (Cherigele and Wuertabulage stations in the lake basins, and Yikeri and Sumujilin stations on the top of sand dunes) in the hinterland of the Badain Jaran Desert in China, with high resolution Google Earth images to analyze the correlation between the wind energy environments and dune morphology. The results of data analysis indicated that both the wind direction and sand drift intensity exhibited notable spatial and temporal variations. The highest level of wind activity was observed in spring. Northwesterly and northeasterly winds were the dominant in the Badain Jaran Desert. At the Cherigele, Wuertabulage, and Yikeri stations, the drift potential (DP) was below 200.00 vector units (VU). The wind energy environments in most areas could be classified as low-energy environments. The resultant drift direction differed at different stations and in different seasons, but the overall direction was mainly the southeast. The resultant drift potential (RDP)/DP ratio was greater than 0.30 in most parts of the study area, suggesting that the wind regimes mainly exhibited unimodal or bimodal characteristics. Differences between the thermodynamic properties and the unique landscape settings of lakes and sand dunes could alter the local circulation and intensify the complexity of the wind regimes. The wind regimes were weaker in the lake basins than on the top of sand dunes. Transverse dunes were the most dominant types of sand dunes in the study area, and the wind regimes at most stations were consistent with sand dune types. Wind was thus the main dynamic factor affecting the formation of sand dunes in the Badain Jaran Desert BJD. The results of this study are important for understanding the relationship between the wind regimes and aeolian landforms of the dune field in the deserts.

submitted time 2022-05-25 Cooperative journals:《Journal of Arid Land》 Hits2Downloads0 Comment 0

3. chinaXiv:202205.00017 [pdf]

Glacier mass balance and its impacts on streamflow in a typical inland river basin in the Tianshan Mountains, northwestern China

PENG Jiajia; LI Zhongqin; XU Liping; MA Yuqing; LI Hongliang; ZHAO Weibo; FAN Shuang
Subjects: Geosciences >> Geography

Abstract: Glaciers are known as natural ''solid reservoirs'', and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we used in situ observation data from Urumqi Glacier No. 1, Xinjiang Uygur Autonomous Region, in combination with meteorological data from stations and a digital elevation model, to develop a distributed degree-day model for glaciers in the Urumqi River Basin to simulate glacier mass balance processes and quantify their effect on streamflow during 19802020. The results indicate that the mass loss and the equilibrium line altitude (ELA) of glaciers in the last 41 years had an increasing trend, with the average mass balance and ELA being −0.85 (±0.32) m w.e./a (meter water-equivalent per year) and 4188 m a.s.l., respectively. The glacier mass loss has increased significantly during 19992020, mostly due to the increase in temperature and the extension of ablation season. During 19802011, the average annual glacier meltwater runoff in the Urumqi River Basin was 0.48×108 m3, accounting for 18.56% of the total streamflow. We found that the annual streamflow in different catchments in the Urumqi River Basin had a strong response to the changes in glacier mass balance, especially from July to August, and the glacier meltwater runoff increased significantly. In summary, it is quite possible that the results of this research can provide a reference for the study of glacier water resources in glacier-recharged basins in arid and semi-arid areas.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits2486Downloads147 Comment 0

4. chinaXiv:202205.00019 [pdf]

Application of the InVEST model for assessing water yield and its response to precipitation and land use in the Weihe River Basin, China

WU Changxue; QIU Dexun; GAO Peng; MU Xingmin; ZHAO Guangju
Subjects: Geosciences >> Hydrology

Abstract: With realizing the importance of ecosystem services to society, the efforts to evaluate the ecosystem services have increased. As the largest tributary of the Yellow River, the Weihe River has been endowed with many ecological service functions. Among which, water yield can be a measure of local availability of water and an index for evaluating the conservation function of the region. This study aimed to explore the temporal and spatial variation of water yield and its influencing factors in the Weihe River Basin (WRB), and provide basis for formulating reasonable water resources utilization schemes. Based on the InVEST (integrated valuation of ecosystem services and tradeoffs) model, this study simulated the water yield in the WRB from 1985 to 2019, and discussed the impacts of climatic factors and land use change on water yield by spatial autocorrelation analysis and scenario analysis methods. The results showed that there was a slight increasing trend in water yield in the WRB over the study period with the increasing rate of 4.84 mm/10a and an average depth of 83.14 mm. The main water-producing areas were concentrated along the mainstream of the Weihe River and in the southern basin. Changes in water yield were comprehensively affected by climate and underlying surface factors. Precipitation was the main factor affecting water yield, which was consistent with water yield in time. And there existed significant spatial agglomeration between water yield and precipitation. Land use had little impact on the amount of water yield, but had an impact on its spatial distribution. Water yield was higher in areas with wide distribution of construction land and grassland. Water yield of different land use types were different. Unused land showed the largest water yield capacity, whereas grassland and farmland contributed most to the total water yield. The increasing water yield in the basin indicates an enhanced water supply service function of the ecosystem. These results are of great significance to the water resources management of the WRB.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits2341Downloads141 Comment 0

5. chinaXiv:202205.00020 [pdf]

Study of the intensity and driving factors of land use/cover change in the Yarlung Zangbo River, Nyang Qu River, and Lhasa River region, Qinghai-Tibet Plateau of China

LUO Jing; XIN Liangjie; LIU Fenggui; CHEN Qiong; ZHOU Qiang; ZHANG Yili
Subjects: Geosciences >> Geography

Abstract: Land use/land cover (LULC) is an important part of exploring the interaction between natural environment and human activities and achieving regional sustainable development. Based on the data of LULC types (cropland, forest land, grassland, built-up land, and unused land) from 1990 to 2015, we analysed the intensity and driving factors of land use/cover change (LUCC) in the Yarlung Zangbo River, Nyang Qu River, and Lhasa River (YNL) region, Qinghai-Tibet Plateau of China, using intensity analysis method, cross-linking table method, and spatial econometric model. The results showed that LUCC in the YNL region was nonstationary from 1990 to 2015, showing a change pattern with "fast-slow-fast" and "U-shaped". Built-up land showed a steady increase pattern, while cropland showed a steady decrease pattern. The gain of built-up land mainly came from the loss of cropland. The transition pattern of LUCC in the YNL region was relatively single and stable during 1990–2015. The transition pattern from cropland and forest land to built-up land was a systematic change process of tendency and the transition pattern from grassland and unused land to cropland was a systematic change process of avoidance. The transition process of LUCC was the result of the combined effect of natural environment and social economic development in the YNL region. This study reveals the impact of ecological environment problems caused by human activities on the land resource system and provides scientific support for the study of ecological environment change and sustainable development of the Qinghai-Tibet Plateau.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits2456Downloads120 Comment 0

6. chinaXiv:202205.00021 [pdf]

Scenario simulation of water retention services under land use/cover and climate changes: a case study of the Loess Plateau, China

SUN Dingzhao; LIANG Youjia; PENG Shouzhang
Subjects: Geosciences >> Hydrology

Abstract: Comprehensive assessments of ecosystem services in environments under the influences of human activities and climate change are critical for sustainable regional ecosystem management. Therefore, integrated interdisciplinary modelling has become a major focus of ecosystem service assessment. In this study, we established a model that integrates land use/cover change (LUCC), climate change, and water retention services to evaluate the spatial and temporal variations of water retention services in the Loess Plateau of China in the historical period (2000–2015) and in the future (2020–2050). An improved Markov-Cellular Automata (Markov-CA) model was used to simulate land use/land cover patterns, and ArcGIS 10.2 software was used to simulate and assess water retention services from 2000 to 2050 under six combined scenarios, including three land use/land cover scenarios (historical scenario (HS), ecological protection scenario (EPS), and urban expansion scenario (UES)) and two climate change scenarios (RCP4.5 and RCP8.5, where RCP is the representative concentration pathway). LUCCs in the historical period (2000–2015) and in the future (2020–2050) are dominated by transformations among agricultural land, urban land and grassland. Urban land under UES increased significantly by 0.63×103 km2/a, which was higher than the increase of urban land under HS and EPS. In the Loess Plateau, water yield decreased by 17.20×106 mm and water retention increased by 0.09×106 mm in the historical period (2000–2015), especially in the Interior drainage zone and its surrounding areas. In the future (2020–2050), the pixel means of water yield is higher under RCP4.5 scenario (96.63 mm) than under RCP8.5 scenario (95.46 mm), and the pixel means of water retention is higher under RCP4.5 scenario (1.95 mm) than under RCP8.5 scenario (1.38 mm). RCP4.5-EPS shows the highest total water retention capacity on the plateau scale among the six combined scenarios, with the value of 1.27×106 mm. Ecological restoration projects in the Loess Plateau have enhanced soil and water retention. However, more attention needs to be paid not only to the simultaneous increase in water retention services and evapotranspiration but also to the type and layout of restored vegetation. Furthermore, urbanization needs to be controlled to prevent uncontrollable LUCCs and climate change. Our findings provide reference data for the regional water and land resources management and the sustainable development of socio-ecological systems in the Loess Plateau under LUCC and climate change scenarios.

submitted time 2022-05-09 Cooperative journals:《Journal of Arid Land》 Hits2671Downloads137 Comment 0

7. chinaXiv:202204.00123 [pdf]


Subjects: Geosciences >> Geography

基于第五和第六次全国人口普查数据,运用区域人力资源测算方法、多元线性回归、地理探测器研究方法,分析了新疆县域人力资源时空分布差异及影响因素。结果表明:(12000—2010新疆人力资源总量增加 54.89%,具有分散分布、空间差异增大的特征;人均人力资源水平提升 30.71%,地域差异主要体现为南、北疆差异,呈低值集聚-高值分散的特点。(2)剔除人力资源教育投入的积累性,2000—2010年新疆人力资源总量增加的县(市、区)主要集中在南疆,北疆、东疆以 减少为主,人均人力资源提升程度南疆明显高于北疆、东疆。(3)新疆人均人力资源时空分布差异受多种因素的综合影响,除教育因素外,二三产业从业人员,人均国民生产总值(GDP)、地方财政收入及从事卫生、社会保障人数因子的驱动较为显著。本研究结果可为新时期缩小新疆区域人力资 源发展差异提供参考。

submitted time 2022-04-16 Cooperative journals:《干旱区地理》 Hits2827Downloads210 Comment 0

8. chinaXiv:202204.00130 [pdf]

不同地理环境下“空间贫困陷阱”分异机制比较 ——基于大别山与黄土高原的实证

Subjects: Geosciences >> Geography

脱贫攻坚战的打赢使贫困治理的目光转向缓解相对贫困,脱贫人口与相对贫困人口的重合性决定了集中连片特困地区仍将是我国解决贫困问题的主战场。以大别山区的新县和黄土高原地区的延长县为例,以贫困发生率为因变量,从“人”、“业”、“地”3个维度选取自变量,综合运用空间自相关和地理探测器等方法,解析不同地理环境下贫困空间分异模式与作用机制。结果表明: 大别山区贫困空间集聚为点状和团块状相间分布为主,黄土高原地区则以团块状为主。大别山区 “地”和“业”2个维度对空间贫困作用显著,黄土高原地区则“人”、“业”、“地”
3个维度相对均衡。承载空间“地”的资源丰度带来的生存压力不同两地贫困形成机制的差异所在,黄土高原地区基于足 够的生存资源,在相对封闭的空间中形成3个维度的负向循环累积,而大别山区在资源匮乏作用 下,个体生存理性抉择下选择外出务工,从而打破贫困累积的循环。

submitted time 2022-04-16 Cooperative journals:《干旱区地理》 Hits1945Downloads175 Comment 0

9. chinaXiv:202204.00131 [pdf]

黄河流域旅游经济与生态环境协调发展时空演变及 影响因素探究

Subjects: Geosciences >> Geography

基于黄河流域66个中心城市(市、地区、州、盟)旅游经济系统和生态环境系统的面板数据, 运用耦合协调模型、空间自相关分析及地理探测器等方法,以200820132018年为时间节点,对黄 河流域旅游经济系统与生态环境系统耦合协调水平的时空演变特征以及影响因素进行探析。结果表明:(12008年黄河流域95%的中心城市旅游经济系统与生态环境系统耦合协调水平均处于中度协调及以上等级;2013年黄河流域60%以上的中心城市2个系统耦合协调水平调整为高度协调等级,流域整体呈现“东高西低”的非均匀分布规律;2018年黄河流域88%以上的中心城市2个系统耦合协调水平处于高度协调及以上等级。(2)黄河流域旅游经济系统与生态环境系统协调发展的空间聚类情况逐年调整,流域内上游省(区)冷点显著区不断缩聚,呈组团分布在青海省东部、甘肃省中部等地区;中下游省(区)热点显著区持续向河南省中部、山东省西部等地区移动并聚拢。 3)政府对于旅游业扶持和对生态环境的保护与整治力度及近3 a节能环保支出年均增长率依次 是影响黄河流域2个系统协调发展最重要的驱动力,每万人发明专利拥有量、出租车保有量等驱动 因子的影响效应呈现先缓升后减弱的态势,以科学研究与试验发展经费(Research and develop? mentR&D)支出占国内生产总值(GDP)比重为表征的科技素质教育要素对黄河流域2个系统协调

submitted time 2022-04-16 Cooperative journals:《干旱区地理》 Hits2220Downloads158 Comment 0

10. chinaXiv:202204.00132 [pdf]

干旱区生态移民空间迁移特征与生态影响 ——以甘肃省古浪县为例

张 伟
Subjects: Geosciences >> Geography

生态移民是西部乡村振兴及区域生态保护与修复的有效途径之一,探究生态移民空间迁移 特征与生态影响,有助于区域减贫和生态文明建设以典型的西北干旱生态移民搬迁区域为例, 从县域空间视角出发,通过计算土地利用转移矩阵、动态度、利用归一化植被指数(Normalized dif?
ference vegetation indexNDVI)和植被恢复度(Vegetation restoration degreeVRD)等方法,系统分析 2010—2018年古浪县生态移民空间迁移和植被恢复的时空变化特征。结果表明:(12010—2018 年生态移民空间迁移特征表现为地势由高到低、坡度由陡到缓,交通导向和空间聚集,共计移民 6.24×104人,占全县常住人口的20.20%。(22010—2018年研究区NDVI在时空上呈现南部迁出地持续增长,北部迁入地先降后升的“V”型趋势。整体移民区 NDVI 最小值从 0.10 增至 0.15,增加50.00%NDVI最大值从0.52增至0.72,增加38.46%;移民安置区NDVI最小值从0.10减至0.09,减 10.00%NDVI最大值从0.66增至0.72,增加9.09%。(3)研究区NDVI平均值和VRD呈现持续快 速上升趋势,生态移民对生态环境保护效果显著。其中,南部整体移民区保护效果最为明显,其 NDVI平均值从0.19增至0.42,增加121.05%VRD0.26增至0.75,增加188.46%

submitted time 2022-04-16 Cooperative journals:《干旱区地理》 Hits2332Downloads163 Comment 0

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