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  • Quantitative distinction of the relative actions of climate change and human activities on vegetation evolution in the Yellow River Basin of China during 1981–2019

    分类: 地球科学 >> 地理学 提交时间: 2023-02-07 合作期刊: 《干旱区科学》

    摘要:

    Under the combined influence of climate change and human activities, vegetation ecosystem has undergone profound changes. It can be seen that there are obvious differences in the evolution patterns and driving mechanisms of vegetation ecosystem in different historical periods. Therefore, it is urgent to identify and reveal the dominant factors and their contribution rates in the vegetation change cycle. Based on the data of climate elements (sunshine hours, precipitation and temperature), human activities (population intensity and GDP intensity) and other natural factors (altitude, slope and aspect), this study explored the spatial and temporal evolution patterns of vegetation NDVI in the Yellow River Basin of China from 1989 to 2019 through a residual method, a trend analysis, and a gravity center model, and quantitatively distinguished the relative actions of climate change and human activities on vegetation evolution based on Geodetector model. The results showed that the spatial distribution of vegetation NDVI in the Yellow River Basin showed a decreasing trend from southeast to northwest. During 1981–2019, the temporal variation of vegetation NDVI showed an overall increasing trend. The gravity centers of average vegetation NDVI during the study period was distributed in Zhenyuan County, Gansu Province, and the center moved northeastwards from 1981 to 2019. During 1981–2000 and 2001–2019, the proportion of vegetation restoration areas promoted by the combined action of climate change and human activities was the largest. During the study period (1981–2019), the dominant factors influencing vegetation NDVI shifted from natural factors to human activities. These results could provide decision support for the protection and restoration of vegetation ecosystem in the Yellow River Basin.

  • Biocrust-induced partitioning of soil water between grass and shrub in a desert steppe of Northwest China

    分类: 地球科学 >> 地理学 提交时间: 2023-02-07 合作期刊: 《干旱区科学》

    摘要:Maintaining the stability of exotic sand-binding shrub has become a large challenge in arid and semi-arid grassland ecosystems in northern China. We investigated two kinds of shrublands with different BSCs (biological soil crusts) cover in desert steppe in Northwest China to characterize the water sources of shrub (Caragana intermedia Kuang et H. C. Fu) and grass (Artemisia scoparia Waldst. et Kit.) by stable 18O isotopic. Our results showed that both shrublands were subject to persistent soil water deficiency from 2012 to 2017, the minimum soil depth with CV (coefficient of variation) <15% and SWC (soil water content) <6% was 1.4 m in shrubland with open areas lacking obvious BSC cover, and 0.8 m in shrubland covered by mature BSCs. For C. intermedia, a considerable proportion of water sources pointed to the surface soil. Water from BSCs contributed to averages 22.9% and 17.6% of the total for C. intermedia and A. scoparia, respectively. C. intermedia might use more water from BSCs in rainy season than dry season, in contrast to A. scoparia. The relationship between shrub (or grass) and soil water by δ18O shown significant differences in months, which partly verified the potential trends and relations covered by the high variability of the water source at seasonal scale. More fine roots at 0–5 cm soil layer could be found in the surface soil layer covered by BSCs (8000 cm/m3) than without BSCs (3200 cm/m3), which ensured the possibility of using the surface soil water by C. intermedia. The result implies that even under serious soil water deficiency, C. intermedia can use the surface soil water, leading to the coexistence between C. intermedia and A. scoparia. Different with the result from BSCs in desert areas, the natural withdrawal of artificial C. intermedia from desert steppe will be a long-term process, and the highly competitive relationship between shrubs and grasses also determines that its habitat will be maintained in serious drought state for a long time.

  • Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

    分类: 地球科学 >> 地理学 提交时间: 2023-02-07 合作期刊: 《干旱区科学》

    摘要:Soil water content is a key controlling factor for vegetation restoration in sand dunes. The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems. To determine the influence of vegetation on the hydrological regulation function of sand dunes, we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land, China. The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes. The accumulated deep seepage water of mobile dunes (vegetation coverage<5%) and dunes with vegetation coverage of 18.03%, 27.12%, and 50.65% accounted for 56.53%, 51.82%, 18.98%, and 0.26%, respectively, of the rainfall in the same period. The accumulated lateral migration of water in these dunes accounted for 12.39%, 6.33%, 2.23%, and 7.61% of the rainfall in the same period. The direction and position of the dune slope affected the soil water deep seepage and lateral migration process. The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope. The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope. According to the above results, during the construction of sand-control projects in sandy regions, we suggest that a certain area of mobile dunes (>13.75%) should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems. These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.

  • Check dam extraction from remote sensing images using deep learning and geospatial analysis: A case study in the Yanhe River Basin of the Loess Plateau, China

    分类: 地球科学 >> 地理学 提交时间: 2023-02-07 合作期刊: 《干旱区科学》

    摘要:

    Check dams are widely used on the Loess Plateau in China to control soil and water losses, develop agricultural land, and improve watershed ecology. Detailed information on the number and spatial distribution of check dams is critical for quantitatively evaluating hydrological and ecological effects and planning the construction of new dams. Thus, this study developed a check dam detection framework for broad areas from high-resolution remote sensing images using an ensemble approach of deep learning and geospatial analysis. First, we made a sample dataset of check dams using GaoFen-2 (GF-2) and Google Earth images. Next, we evaluated five popular deep-learning-based object detectors, including Faster R-CNN, You Only Look Once (version 3) (YOLOv3), Cascade R-CNN, YOLOX, and VarifocalNet (VFNet), to identify the best one for check dam detection. Finally, we analyzed the location characteristics of the check dams and used geographical constraints to optimize the detection results. Precision, recall, average precision at intersection over union (IoU) threshold of 0.50 (AP50), IoU threshold of 0.75 (AP75), and average value for 10 IoU thresholds ranging from 0.50–0.95 with a 0.05 step (AP50–95), and inference time were used to evaluate model performance. All the five deep learning networks could identify check dams quickly and accurately, with AP50–95, AP50, and AP75 values higher than 60.0%, 90.0%, and 70.0%, respectively, except for YOLOv3. The VFNet had the best performance, followed by YOLOX. The proposed framework was tested in the Yanhe River Basin and yielded promising results, with a recall rate of 87.0% for 521 check dams. Furthermore, the geographic analysis deleted about 50% of the false detection boxes, increasing the identification accuracy of check dams from 78.6% to 87.6%. Simultaneously, this framework recognized 568 recently constructed check dams and small check dams not recorded in the known check dam survey datasets. The extraction results will support efficient watershed management and guide future studies on soil erosion in the Loess Plateau.

  • Spatiotemporal evolution and prediction of habitat quality in Hohhot City of China based on the InVEST and CA-Markov models

    分类: 地球科学 >> 地理学 提交时间: 2023-02-07 合作期刊: 《干旱区科学》

    摘要:With the acceleration of urbanization, changes in the urban ecological environment and landscape pattern have led to a series of prominent ecological environmental problems. In order to better coordinate the balanced relationship between city and ecological environment, we selected land use change data to evaluate the habitat quality in Hohhot City of China, which is of great practical significance for regional urban and economic development. Thus, the integrated valuation of ecosystem services and tradeoffs (InVEST) and Cellular Automata-Markov (CA-Markov) models were used to analyze, predict, and explore the Spatiotemporal evolution path and characteristics of urban land use, and forecast the typical evolution pattern of land use in 2030. The results showed that the land use types in Hohhot City changed significantly from 2000 to 2020, and the biggest change took place in cultivated land, grassland, shrub, and artificial surface. The decrease of cultivated land area and the increase of artificial surface area were the main impact trend of land use change. The average value of habitat quality had been decreasing continuously from 2000 to 2020, and the values of habitat degradation were 0.2605, 0.2494, and 0.2934 in 2000, 2010, and 2020, respectively, showing a decreasing trend. The decrease of habitat quality was caused by the needs of economic development and urban construction, as well as the impact of land occupation. During this evolution, many cultivated land and urban grassland had been converted into construction land. The simulated land use changes in 2030 are basically the same as those during 2000–2020, and the habitat quality will still be declining. The regional changes are influenced by the urban rapid development and industrial layout. These results can provide decision-making reference for regional urban planning and management as well as habitat quality evaluation.

  • Spatiotemporal characteristics and influencing factors of ecosystem services in Central Asia

    分类: 地球科学 >> 地理学 提交时间: 2023-02-06 合作期刊: 《干旱区科学》

    摘要:Land use/land cover (LULC) change and climate change are two major factors affecting the provision of ecosystem services which are closely related to human well-being. However, a clear understanding of the relationships between these two factors and ecosystem services in Central Asia is still lacking. This study aimed to comprehensively assess ecosystem services in Central Asia and analyze how they are impacted by changes in LULC and climate. The spatiotemporal patterns of three ecosystem services during the period of 2000–2015, namely the net primary productivity (NPP), water yield, and soil retention, were quantified and mapped by the Carnegie-Ames-Stanford Approach (CASA) model, Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, and Revised Universal Soil Loss Equation (RUSLE). Scenarios were used to determine the relative importance and combined effect of LULC change and climate change on ecosystem services. Then, the relationships between climate factors (precipitation and temperature) and ecosystem services, as well as between LULC change and ecosystem services, were further discussed. The results showed that the high values of ecosystem services appeared in the southeast of Central Asia. Among the six biomes (alpine forest region (AFR), alpine meadow region (AMR), typical steppe region (TSR), desert steppe region (DSR), desert region (DR), and lake region (LR)), the values of ecosystem services followed the order of AFR>AMR>TSR>DSR> DR>LR. In addition, the values of ecosystem services fluctuated during the period of 2000–2015, with the most significant decreases observed in the southeast mountainous area and northwest of Central Asia. LULC change had a greater impact on the NPP, while climate change had a stronger influence on the water yield and soil retention. The combined LULC change and climate change exhibited a significant synergistic effect on ecosystem services in most of Central Asia. Moreover, ecosystem services were more strongly and positively correlated with precipitation than with temperature. The greening of desert areas and forest land expansion could improve ecosystem services, but unreasonable development of cropland and urbanization have had an adverse impact on ecosystem services. According to the results, ecological stability in Central Asia can be achieved through the natural vegetation protection, reasonable urbanization, and ecological agriculture development.

  • 内蒙古草地资源的生态足迹及其可持续利用分析

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:可持续性可通过区域生态足迹水平进行衡量。采用净初级生产力构建了内蒙古各盟(市)草地资源的均衡因子和产量因子。以每5 a为一期,测算了内蒙古草地1990—2020年的生态足迹,并结合人口分布数据刻画了生态足迹的空间分布状况;在此基础上应用土地可持续模型评价了内蒙古草地资源的可持续性。结果表明:(1)内蒙古各盟(市)草地的产量因子差异较大,整体呈东高西低的特点。(2)生态承载力在空间上也呈东高西低特点,30 a人均生态承载力整体呈小幅度下降趋势。(3)人均生态足迹逐期上升,2000—2005年由生态盈余转变为生态赤字。生态足迹较高的区域集中在通辽市、锡林浩特市、二连浩特市、乌兰察布市南部和鄂尔多斯市东部地区。(4)内蒙古草地资源可持续性逐期下降,由1990年的中度可持续性退化为2020年的弱不可持续性。可持续性退化严重的区域集中在呼和浩特市、包头市和乌海市。研究结果旨在为内蒙古草地资源的可持续利用提供可靠的理论基础。

  • 新疆区域经济联系网络时空格局演变

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:以新疆15个地州市为研究对象,运用区域流强度模型和引力模型,分析2010—2019年新疆辐射能力以及区域间的经济联系,采用社会网络分析方法探究经济联系网络结构演变特征,为优化新疆区域经济网络结构和区域经济一体化发展提出建议。结果表明:(1)区域流强度整体表现为北高南低的发展格局,10 a间平均提升率达60%,以乌鲁木齐市和喀什地区为首区域流强度相关指标增长最为显著,但中心区域的辐射带动能力总体较弱。(2)2019年新疆弱经济联系数量占比降
    至48.57%,低等级经济联系格局显著,逐步形成以乌鲁木齐市为中心、克拉玛依市和石河子市为次中心的放射状空间联系格局,10 a间经济联系整体略有增长,过程中虹吸效应远大于涓滴效应。(3)网络中心势2019年达63.61%,整体中心性水平以极化效应为主,区域经济发展不均衡,凝聚子群内部成员不断发生变化,空间分割现象显著。新疆整体经济联系时空网络格局“核心-边缘”现象显著,呈现出“东北强、西南弱”的空间分布格局。

  • 新疆非物质文化遗产分布特征及旅游活化机制研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:以新疆非物质文化遗产资源为研究对象,基于实地调研与文献史料,系统分析了新疆非遗旅游活化发展现状、模式及存在的问题,并运用GIS空间分析技术探索新疆非遗的空间分布特征,借助SPSS软件探析了非遗与旅游发展之间的相关关系,进而归纳了非遗旅游活化发展的机制与模式。结果表明:(1)新疆非遗资源类型结构、数量分布具有较为显著的差异化特征。新疆非遗旅游活化发展态势良好,且活化模式逐渐多元化。(2)国家级非遗与自治区级非遗在省域空间层面以极核区、高度密集区、次级密集区和面状区域为主要分布特征,呈现出不均衡的集聚特征格局。(3)不同地区的非遗资源丰裕度对旅游业发展有显著的正向影响,非遗资源密集地区的旅游业发展水平相对较好,而非遗资源稀缺地区的旅游发展相对缓慢。依据上述分析结果,提出新疆非遗旅游活化发展机制,以旅游为载体对文化遗产进行活化,推动非遗与旅游的良性互动发展。

  • 新疆城市规模分布与自然地理相关性分析

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:如何实现人口、城市规模和自然地理系统的协调及可持续发展,是城市化中人地关系面临的难题。以新疆91个县域单元为研究对象,基于研究区全域、六大地貌类型和七大水系分区3个空间维度,运用位序-规模法和人口Lorenz曲线法,对城市规模体系和人口分布格局量化分析,探究了新疆城市规模分布与地貌、水系空间分布的相关性。结果表明:(1)地貌类型区系统规模分布相关系数为0.897,水系分区系统规模分布相关系数为0.951,表明城镇规模格局与水系地理因子关系更紧密。(2)准噶尔盆地与天山北麓诸河区是2个突出的人口分布聚集单元,同时是地理类型高度叠加区,呈现出城市规模与自然地理结合的空间极化区。(3)新疆各自然地理单元城市人口分布的异质性表现突出,地貌类型单元内人口集疏格局鲜明,水系分区单元内人口分布相对均衡,其中天山北麓诸河区人口集聚程度较高。总体来看,新疆城市人口规模区域差异特征显著,城市规模等级结构存在断层现象,城市体系发育不成熟,建议加强中等城市规模的发展,完善新疆全域的城市格局。

  • 中国资源型城市生态系统服务价值评价 ——基于Meta模型视角

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:资源型城市是基础能源和重要原材料的供应地,但由于资源衰减和缺乏统筹规划等原因,
    这些城市面临经济结构失衡、生态环境破坏严重等较大压力。因此,将资源型城市自然环境经济价值进行成本效益分析,对于改善资源型城市的人居环境,解决生态环境问题具有一定的指导意义。应用Meta模型,以城市居民户均支付意愿为视角,对资源型城市生态系统服务价值进行评价,并运用价值转移函数对公园价值进行评估。结果表明:(1)以生态系统服务特征变量得到的价值较高,对资源型城市生态系统服务具有显著影响。(2)除森林外,其他自然类型特征变量的环境资源得到的生态系统服务价值较低。(3)城市居民收入越高支付能力越强,在支付工具的选择上,人们更倾向于利用捐款和入门费的方式进行支付。(4)公园生态系统服务价值在1790.26×104~31016.00×104元,并且按照东部、中部、西部次序排列。根据研究结论,提出进一步增加资源型城市的森林面积,强化生态效益产出,提升生态系统服务功能,提高居民可支配收入,增加捐赠和入门费等自愿性支付工具使用,以此不断提高城市生态系统服务价值。

  • 基于不同尺度的中国运动健身场所空间差异及 影响因素研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:运动健身场所是开展全民健身运动的重要推手,探明运动健身场所的区域差异及影响因素对推动运动健身场所的建设、推进“健康中国”战略有重要作用。从省级、城市群以及地级市3个尺度出发,运用总体分异测度指数(Global differentiation index,GDI)、Moran’s I 指数、热点分析探讨运动健身场所的空间差异,采用Pearson相关系数、灰色关联度以及地理探测器等方法分析运动健身场所分布的影响因素。结果表明:(1)运动健身场所数量与每万人拥有运动健身场所数量主要集中分布于东部地区,而西部地区除成都、重庆外,其余省区均分布较少。(2)运动健身场所数量与每万人拥有运动健身场所数量的GDI随着尺度的缩小而扩大,城市群尺度中,优化提升类差异最大,而发展壮大类差异最小。(3)经济总量和人口数量是运动健身场所集中的重要驱动因素,人口数量与城镇人口占比的交互作用最强。在城市群尺度上,受教育程度和城市规模大小是运动场所的重要影响因素。而在地级市尺度上,建成区面积占辖区面积比重对运动健身场所的影响更为显著。

  • 红色旅游高质量发展评价指标体系与培育路径研究 ——以红色旅游城市为例

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:基于五大发展理念构建了红色旅游高质量发展评价体系,选取12个重点红色旅游城市为研究案例,探究了其红色旅游高质量演化特征,并运用多案例的定性比较法和典型案例的网络文本分析提出了高质量发展的培育路径。结果表明:(1)案例地红色旅游高质量发展水平整体不高,地区差异显著,六大子系统中增长动力、增长结构和增长方式上升水平尤为显著。(2)案例地红色旅游高质量发展存在极差化特征。具体引致各发展类型失配的障碍系统存在差异,且其主导障碍
    因素呈现由内部资源优势向外部环境协调转化的过程。(3)多案例地驱动机制分析可知,红色旅游高质量发展是六大子系统共同作用的结果,其中增长动力是核心因子,增长结构是共生因子,增长方式是非敏感因子,增长形态是敏感因子,增长成果是外部性因子,增长基础是支撑因子。(4)典型个案的内容分析提炼出了全方位扩大红色旅游的正外部性效应、优化数字经济格局下的红色旅游共生环境、激发红色研学的大众旅游市场需求共三大关键培育路径。

  • 草甸草原降水特征与土壤水分对降水脉动响应 ——以呼伦贝尔草原额尔古纳市为例

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:利用额尔古纳牧业气象试验站降水量与土壤水分数据,通过降水与土壤水分动态变化及转化过程分析,确定土壤水分响应的降水临界值与不同降水级别引起土壤水分响应的概率,构建了降水过程量与土壤水分增量函数关系。结果表明:(1)研究区降水量呈“先降后升”变化趋势,年内降水量呈单峰型分布。(2)研究区以无降水天气为主,降水又以小降水事件占主导,大降水事件发生频次低、过程降水量大,小降水事件则相反。(3)可以引起研究区0~50 cm各层土壤水分响应的降水临界值分别为8.1 mm、10.1 mm、19.0 mm、27.9 mm和31.6 mm,小雨仅能引起0~10 cm土壤水分响应的概率为28.6%,中雨不能引起40~50 cm土壤水分的响应。(4)降水量与0~10 cm和10~20 cm土壤水分达到最大值时的滞后时间呈现出极显著负相关关系,与20~30 cm呈显著负相关关系,0~30 cm各层土壤水分达到最大值时的滞后时间与降水量符合幂函数关系。(5)降水量和0~50 cm土壤水分增量均呈现出极显著正相关关系,降水量与0~10 cm和10~20 cm土壤水分增量符合线性关系,与20~30 cm、30~40 cm和40~50 cm土壤水分增量符合多项式关系。检验结果表明,构建的函数模型可以较好地模拟研究区0~30 cm各层水分增量。研究结果为地方政府抗旱减灾提供了科学依据。

  • 喜马拉雅地区叶如藏布流域冰川和冰湖 变化遥感监测研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:叶如藏布流域冰川和冰湖众多,冰川融水是当地重要的淡水资源,是冰湖扩张的重要补给,冰湖溃决是当地潜在的自然灾害,因此分析该区域冰川和冰湖的现状与变化特征具有重要的现实意义。基于Landsat系列遥感影像,分析1990—2020年叶如藏布流域冰川和冰湖的分布与变化特征。结果表明:(1)近30 a来叶如藏布流域冰川面积整体呈退缩趋势,由1990年167.80 km2退缩到2020 年128.92 km2,共退缩38.88 km2,年均退缩率为0.77%·a-1,且研究区冰川主要分布在海拔
    5800~6400 m之间,集中分布在5°~20°的坡度上。(2)与冰川变化趋势相反,研究时段冰湖整体表现为扩张趋势,由1990年5.72 km2增加到2020年8.81 km2,30 a共增加3.09 km2,年均增长率为1.80%·a-1。(3)冰湖主要分布在海拔5000~5600 m范围内,坡度在0~10°分布面积较多,表碛覆盖型冰川与非表碛覆盖型冰川对冰湖有着不同程度的影响。(4)1990—2017年叶如藏布流域温度与降水波动较大,温度整体呈上升趋势,降水量则波动下降,导致叶如藏布流域的冰川消融,冰湖扩张。通过上述研究以期为叶如藏布流域地区提供详细的冰川和冰湖面积分布与变化特征基础数据,为防灾减灾提供一定的支撑。

  • 喜马拉雅地区叶如藏布流域冰川和冰湖 变化遥感监测研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:叶如藏布流域冰川和冰湖众多,冰川融水是当地重要的淡水资源,是冰湖扩张的重要补给,冰湖溃决是当地潜在的自然灾害,因此分析该区域冰川和冰湖的现状与变化特征具有重要的现实意义。基于Landsat系列遥感影像,分析1990—2020年叶如藏布流域冰川和冰湖的分布与变化特征。结果表明:(1)近30 a来叶如藏布流域冰川面积整体呈退缩趋势,由1990年167.80 km2退缩到2020 年128.92 km2,共退缩38.88 km2,年均退缩率为0.77%·a-1,且研究区冰川主要分布在海拔
    5800~6400 m之间,集中分布在5°~20°的坡度上。(2)与冰川变化趋势相反,研究时段冰湖整体表现为扩张趋势,由1990年5.72 km2增加到2020年8.81 km2,30 a共增加3.09 km2,年均增长率为1.80%·a-1。(3)冰湖主要分布在海拔5000~5600 m范围内,坡度在0~10°分布面积较多,表碛覆盖型冰川与非表碛覆盖型冰川对冰湖有着不同程度的影响。(4)1990—2017年叶如藏布流域温度与降水波动较大,温度整体呈上升趋势,降水量则波动下降,导致叶如藏布流域的冰川消融,冰湖扩张。通过上述研究以期为叶如藏布流域地区提供详细的冰川和冰湖面积分布与变化特征基础数据,为防灾减灾提供一定的支撑。

  • 基于探地雷达的土体构型无损探测方法研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:土体构型对土壤水分、溶质运移过程和作物成长等有显著影响,常规测量采用人工挖土壤剖面取样、实验室化验分析等方法,其周期长效率低。针对以上问题,以探地雷达波形及其图像为研究对象,从检测土体构型的属性(层次、层厚、土质)入手,提出了一种使用探地雷达快速测量土壤土体构型的无损探测方法。基于探地雷达波形图像的纵向梯度信息能够反应土壤分层,采用包络检波法从探地雷达回波中提取包络信号,利用Hilbert分析其瞬时相位来确定分层位置;鉴于土
    壤介电常数与雷达回波振幅的关系,采用探地雷达回波振幅反演各层介电常数,由介电常数推算雷达波在土壤中的传播速度,以此得到土壤剖面各层厚度;根据探地雷达波形图的图像噪声与土壤砂壤比之间存在定量关系,提出采用主成分分析方法对每一层土质的图像进行噪声估计求得各层土壤的含砂量,结合支持向量机进而辨识各层土壤土质。建立涵盖地域信息、土壤指标、探测信息、图像多特征融合信息的土体构型知识库,并编制快速识别土壤土体构型的信息系统,在内蒙古
    自治区呼和浩特市周边2个试验基地、6个采样点、4类土壤土体构型使用该方法进行野外探测验证。研究表明:在上述地区地表以下1 m范围内的土体构型识别正确率达到94%以上;探测的每层土壤厚度相对测量误差小于10%。该研究方法为土体构型快速检测应用提供了一种新的中观探测思路。

  • 基于Sentinel-2 时间序列数据及物候特征的 棉花种植区提取

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:棉花是中国重要的经济作物,在新疆大面积种植。及时、准确获取棉花种植面积,对农业政策制定与农业经济发展有重要意义。以渭干河—库车河三角洲绿洲棉花为主要研究对象,利用2018—2020年(1景/1月)36景哨兵2号(Sentinel-2)数据,构建归一化植被指数(Normalize differ⁃ence vegetation index,NDVI)和红边归一化植被指数(Red edge normalize difference vegetation index,RENDVI783)时序数据;采用Savitzky-Golay(S-G)滤波法对时序数据进行平滑、重构并提取11个物候特征;利用袋外误差法对11个物候特征进行特征优选;在此基础上利用重构后的时序数据(NDVI Fit)、(RENDVI783 Fit)、物候特征(RENDVI783 Ph)、物候特征优选组合构建6种不同的特征数据集,利
    用随机森林分类(RFC)方法分别进行分类和提取,并采用最大似然分类方法和支持向量机分类方法对分类效果进行验证。结果表明:(1)NDVI和RENDVI783时序数据变化趋势较为一致,棉花在5月(苗期)到8月初(开花盛期)有明显的上升趋势,在8月末至9月(花铃期)达到峰值。相比NDVI,红边波段构成的RENDVI783时序曲线峰值从0.7提高到0.9,棉花区分效果更佳。(2)11个物候特征中拟合函数最大值、生长季长度、生长季振幅、生长季结束、生长季大积分和生长季小积分对分类的贡献性最大,重要性得分分别为1.43、1.40、1.23、1.16、1.02和1.01。(3)RFC方法对特征数据集(RENDVI783 Fit+物候特征优选组合)分类精度最佳。总体精度和Kappa 系数分别为92.20%和0.92。(4)研究区内棉花分类精度达到了91.02%,种植面积约为3424 km2,占研究区总面积的24.67%。

  • 基于GRACE数据的黄河流域地下水储量变化 与人口暴露研究

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:近年来黄河流域人与水资源矛盾愈发突出,尤其是地下水储量的过度消耗已成为限制该区域人与自然和谐发展的主要矛盾之一。基于重力反演与气候实验卫星数据和全球陆面数据同化系数数据,根据流域水循环与水量平衡原理,测算2003—2016年黄河流域地下水储量的变化情况,在探究其时空变化特征的基础上,识别了地下水储量下降明显区域的人口暴露度。结果表明:(1)空间分布上,黄河流域地下水储量西多东少,由西向东下降程度不断加剧,且下降区域呈现由下游
    向中上游扩散的态势。下降区域主要集中在中东部地区,变化等级以较剧烈减少和剧烈减少为主。(2)时间变化上,2003—2016年黄河流域地下水储量整体呈下降趋势,年均降幅为5.93 mm·a-1。其中,2004—2016年为连续下降,2015—2016年的下降幅度最大;另外,地下水储量时间变化存在季节效应,地下水储量下降幅度春季最大、冬季次之、秋季再次之、夏季最小。(3)地下水暴露风险状态下的地级市人口密度在空间上呈东高西低、中部交错分布的状态,暴露风险人口密度最大地级市共16个;地下水储量下降人口累积百分比呈现明显上升的趋势,在2016年达到最大值。研究
    结果以期为黄河流域地下水资源可持续利用提供科学参考。

  • 2013—2020 年塔里木河流域胡杨林生态恢复成效评估

    分类: 地球科学 >> 地理学 提交时间: 2023-02-02 合作期刊: 《干旱区地理》

    摘要:生态输水是塔里木河流域退化胡杨林生态恢复的主要措施,及时监测和准确评估其恢复成效是优化输水策略、完善胡杨林修复体系的关键。以2013年以来8个胡杨林区为研究对象,基于中高分辨率遥感数据监测不同胡杨林区生态输水前后植被面积、长势及植被覆盖度的时序变化,探讨胡杨林恢复与生态输水的关系。结果表明:(1)2016 年以来整个流域累计漫溢水面为2172.96 km2,占林区总面积的4.39%,主要分布在输水通道两侧及末端10 km范围内。(2)输水前后林区植被整体呈现由退化到恢复的转变,林区生态恢复水平与年最大漫溢面积显著正相关。(3)生态恢复成效评估表明,生态恢复最显著的区域是塔里木河中上游和叶尔羌河下游的夏马勒林场,但整个流域远离输水通道的胡杨林仍有退化趋势。合理规划输水通道建设,扩大胡杨林区的受水范围是退化胡杨林生态恢复的关键。