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  • Estimation of rock Fe content based on hyperspectral indices

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:Information on the Fe content of bare rocks is needed for implementing geochemical processes and identifying mines. However, the influence of Fe content on the spectra of bare rocks has not been thoroughly analyzed in previous studies. The Saur Mountain region within the Hoboksar of the Russell Hill depression was selected as the study area. Specifically, we analyzed six hyperspectral indices related to rock Fe content based on laboratory measurements (Dataset I) and field measurements (Dataset II). In situ field measurements were acquired to verify the laboratory measurements. Fe content of the rock samples collected from different fresh and weathered rock surfaces were divided into six levels to reveal the spatial distributions of Fe content of these samples. In addition, we clearly displayed wavelengths with obvious characteristics by analyzing the spectra of these samples. The results of this work indicated that Fe content estimation models based on the fresh rock surface measurements in the laboratory can be applied to in situ field or satellite-based measurements of Fe content of the weathered rock surfaces. It is not the best way to use only the single wavelengths reflectance at all absorption wavelengths or the depth of these absorption features to estimate Fe content. Based on sample data analysis, the comparison with other indices revealed that the performance of the modified normalized difference index is the best indicator for estimating rock Fe content, with R2 values of 0.45 and 0.40 corresponding to datasets I and II, respectively. Hence, the modified normalized difference index (the wavelengths of 2220, 2290, and 2370 nm) identified in this study could contribute considerably to improve the identification accuracy of rock Fe content in the bare rock areas. The method proposed in this study can obviously provide an efficient solution for large-scale rock Fe content measurements in the field.

  • Land use/land cover change responses to ecological water conveyance in the lower reaches of Tarim River, China

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:The Tarim River is the longest inland river in China and is considered as an important river to protect the oasis economy and environment of the Tarim Basin. However, excessive exploitation and over-utilization of natural resources, particularly water resources, have triggered a series of ecological and environmental problems, such as the reduction in the volume of water in the main river, deterioration of water quality, drying up of downstream rivers, degradation of vegetation, and land desertification. In this study, the land use/land cover change (LUCC) responses to ecological water conveyance in the lower reaches of the Tarim River were investigated using ENVI (Environment for Visualizing Images) and GIS (Geographic Information System) data analysis software for the period of 1990–2018. Multi-temporal remote sensing images and ecological water conveyance data from 1990 to 2018 were used. The results indicate that LUCC covered an area of 2644.34 km2 during this period, accounting for 15.79% of the total study area. From 1990 to 2018, wetland, farmland, forestland, and artificial surfaces increased by 533.42 km2 (216.77%), 446.68 km2 (123.66%), 284.55 km2 (5.67%), and 57.51 km2 (217.96%), respectively, whereas areas covered by grassland and other land use/land cover types, such as Gobi, bare soil, and deserts, decreased by 103.34 km2 (14.31%) and 1218.83 km2 (11.75%), respectively. Vegetation area decreased first and then increased, with the order of 2010<2000<1990<2018. LUCC in the overflow and stagnant areas in the lower reaches of the Tarim River was mainly characterized by fragmentation, irregularity, and complexity. By analyzing the LUCC responses to 19 rounds of ecological water conveyance in the lower reaches of the Tarim River from 2000 to the end of 2018, we proposed guidelines for the rational development and utilization of water and soil resources and formulation of strategies for the sustainable development of the lower reaches of the Tarim River. This study provides scientific guidance for optimal scheduling of water resources in the region.

  • Mass balance of saline lakes considering inflow loads of rivers and groundwater: the case of Lake Issyk- Kul, Central Asia

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:This study aimed to elucidate the influence of inflow water on the salinity concentration process of a saline lake and the mass balance of Lake Issyk-Kul, a tectonic saltwater lake in Kyrgyzstan. Based on the survey results and meteorological data from 2012 to 2015, we analyzed the dissolved chemical composition loads due to water inflow. Then, we discussed the relationship between the increase in salinity and water inflow into the lake. Through the water quality analysis data, we used the tank model to estimate the river inflow and analyze the loads by the L-Q curve. The groundwater loads were then estimated from the average annual increase in salinity of the lake over a period of 30 a. The results suggest that Lake Issyk-Kul was temporarily freshened between about AD 1500 and 1800 when an outflowing river existed, and thereafter, it became a closed lake in AD 1800 and continued to remain a saline lake until present. The chemical components that cause salinization are supplied from the rivers and groundwater in the catchment area, and when they flow into the lake, Ca2+, HCO3− and Mg2+ precipitate as CaCO3 and MgCO3. These compounds were confirmed to have been left on the lakeshore as evaporite. The model analysis showed that 1.67 mg/L of Ca2+ and Mg2+ supplied from rivers and groundwater are precipitated as evaporite and in other forms per year. On the other hand, salinity continues to remain in the lake water at a rate of 27.5 mg/L per year. These are the main causes of increased salinity in Lake Issyk-Kul. Since Na+ and Cl– are considered to be derived from geothermal water, they will continue to flow in regardless of the effects of human activities. Therefore, as long as these components are accumulated in Lake Issyk-Kul as a closed lake, the salinity will continue to increase in the future.

  • Drought and flood characteristics in the farming- pastoral ecotone of northern China based on the Standardized Precipitation Index

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:The farming-pastoral ecotone of northern China (FPENC) provides an important ecological barrier which restrains the invasion of desert into Northwest China. Studying drought and flood characteristics in the FPENC can provide scientific support and practical basis for the protection of the FPENC. Based on monthly precipitation data from 115 meteorological stations, we determined the changes in climate and the temporal and spatial variations of drought and flood occurrence in the FPENC during 1960–2020 using the Standardized Precipitation Index (SPI), Morlet wavelet transform, and inverse distance weighted interpolation method. Annual precipitation in the FPENC showed a slightly increasing trend from 1960 to 2020, with an increasing rate of about 1.15 mm/a. The interannual SPI exhibited obvious fluctuations, showing an overall non-significant upward trend (increasing rate of 0.02/a). Therefore, the study area showed a wetting trend in recent years. Drought and flood disasters mainly occurred on an interannual change cycle of 2–6 and 9–17 a, respectively. In the future, a tendency towards drought can be expected in the FPENC. The temporal and spatial distribution of drought and flood differed in the northwestern, northern, and northeastern segments of the FPENC, and most of the drought and flood disasters occurred in local areas. Severe and extreme drought disasters were concentrated in the northwestern and northeastern segments, and severe and extreme flood disasters were mainly in the northeastern segment. Drought was most frequent in the northwestern segment, the central part of the northeastern segment, and the northern part of the northern segment. Flood was most frequent in the western part of the northwestern segment, the eastern part of the northeastern segment, and the eastern and western parts of the northern segment. The accurate evaluation of the degrees of drought and flood disasters in the FPENC will provide scientific basis for the regional climate study and critical information on which to base decisions regarding environmental protection and socio-economic development in this region.

  • Characterizing the spatiotemporal variations of evapotranspiration and aridity index in mid-western China from 2001 to 2016

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:Mid-western China is one of the most sensitive and fragile areas on the Earth. Evapotranspiration (ET) is a key part of hydrological cycle in these areas and is affected by both global climate change and human activities. The dynamic changes in ET and potential evapotranspiration (PET), which can reflect water consumption and demand, are still unclear, and there is a lack of predictive capacity on drought severity. In this study, we used global MODIS (moderate-resolution imaging spectroradiometer) terrestrial ET (MOD16) products, Morlet wavelet analysis, and simple linear regression to investigate the spatiotemporal variations of ET, PET, reference ET (ET0), and aridity index (AI) in mid-western pastoral regions of China (including Gansu Province, Qinghai Province, Ningxia Hui Autonomous Region, and part of Inner Mongolia Autonomous Region) from 2001 to 2016. The results showed that the overall ET gradually increased from east to southwest in the study area. Actual ET showed an increasing trend, whereas PET tended to decrease from 2001 to 2016. The change in ET was affected by vegetation types. During the study period, the average annual ET0 and AI tended to decrease. At the monthly scale within a year, AI value decreased from January to July and then increased. The interannual variations of ET0 and AI showed periodicity with a main period of 14 a, and two other periodicities of 11 and 5 a. This study showed that in recent years, drought in these pastoral regions of mid-western China has been alleviated. Therefore, it is foreseeable that the demand for irrigation water for agricultural production in these regions will decrease.

  • Contribution of underlying terrain to sand dunes: evidence from the Qaidam Basin, Northwest China

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:Underlying terrain strongly influences dune formation. However, the impacts of underlying terrain on the dune formation are poorly studied. In the present research, we focused on dunes that formed in the alluvial fans and dry salt flats in the Qaidam Basin, Northwest China. We quantified the dunes' sediment characteristics on different types of underlying terrain and the terrain' effects on the surface quartz grains by analyzing grain-size distribution, soluble salt contents and grain surface micro-textures. Results showed that barchan dunes were dominated by medium sands with a unimodal frequency distribution, whose peak corresponded to the saltation load. Linear dunes were mainly composed of fine sands with a bimodal frequency distribution, whose main peak represented the saltation load, and whose secondary peak represented the modified saltation or suspension load. Sand was transported from source area by running water (inland rivers) over short distances and by wind over relatively longer distances. Thus, quartz grains had poor roundness and were dominated by sub-angular and angular shapes. Surface micro-textures indicated that dune sands were successively transported by exogenic agents (glaciation, fluviation and wind). Soluble salt contents were low in dunes that developed in the alluvial fans, which represented a low-energy chemical environment, so the grain surface micro-textures mainly resulted from mechanical erosion, with weak micro-textures formed by SiO2 solution and precipitation. However, soluble salt contents were much higher in dunes that developed in the dry salt flats, which indicated a high-energy chemical environment. Therefore, in addition to micro-structures caused by mechanical erosion, micro-textures formed by SiO2 solution and precipitation also well developed. Our results improve understanding of the sediment characteristics of dune sands and the effects of underlying terrain on dune development in the Qaidam Basin, China.

  • Effects of restoration modes on the spatial distribu¬tion of soil physical properties after land consolida¬tion: a multifractal analysis

    分类: 地球科学 >> 地理学 提交时间: 2021-12-30 合作期刊: 《干旱区科学》

    摘要:soil physical properties (SPP) are considered to be important indices that reflect soil structure, hydrological conditions and soil quality. It is of substantial interest to study the spatial distribution of SPP owing to the high spatial variability caused by land consolidation under various land restoration modes in excavated farmland in the loess hilly area of China. In our study, three land restoration modes were selected including natural restoration land (NR), alfalfa land (AL) and maize land (ML). Soil texture composition, including the contents of clay, silt and sand, field capacity (FC), saturated conductivity (Ks) and bulk density (BD) were determined using a multifractal analysis. SPP were found to possess variable characteristics, although land consolidation destroyed the soil structure and decreased the spatial autocorrelation. Furthermore, SPP varied with land restoration and could be illustrated by the multifractal parameters of D1, ∆D, ∆α and ∆f in different modes of land restoration. Owing to multiple compaction from large machinery in the surface soil, soil particles were fine-grained and increased the spatial variability in soil texture composition under all the land restoration modes. Plough numbers and vegetative root characteristics had the most significant impacts on the improvement in SPP, which resulted in the best spatial distribution characteristics of SPP found in ML compared with those in AL and NR. In addition, compared with ML, ∆α values of NR and AL were 4.9- and 3.0-fold that of FC, respectively, and ∆α values of NR and AL were 2.3- and 1.5-fold higher than those of Ks, respectively. These results indicate that SPP can be rapidly improved by increasing plough numbers and planting vegetation types after land consolidation. Thus, we conclude that ML is an optimal land restoration mode that results in favorable conditions to rapidly improve SPP.

  • 生态移民区“三生”用地变化对生态系统服务的影响 ——以宁夏红寺堡区为例

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 土地系统运行以土地可持续利用与人类福祉为准绳。以全国最大的生态移民区红寺堡区 为例,基于不同计量方法和 GIS 空间分析法,对红寺堡区 2000—2018 年的“三生”用地转型及生态 服务变化进行定量研究。结果表明:(1)红寺堡区基本形成以中部灌区生活生产、生产生态空间为 主,周边为生态空间的“三生”格局,国土开发格局逐渐优化。(2)生产生态用地减少 3.42×104 hm2, 生态用地增加 1.24×104 hm2,生态生产用地增加 0.16×104 hm2,生活生产用地增加 2.02×104 hm2。(3) 生态系统服务价值共增加 11.18×108 元。植被恢复是生态系统服务价值增加的主因,而建设用地对 其他用地的侵占则是导致生态系统服务价值降低的主因。(4)协同推进山水林田湖草治理,做好已有生态用地的质量提升和绿地生态网络建设,通过优化生态系统服务结构提升区域生态系统的服务功能,从而实现生产空间的集约化发展、生态空间的提质增效及生活空间的优美宜居

  • 新疆县市“三生”功能时空变化及耦合协调性分析

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 基于“生产-生活-生态”功能视角构建评价体系并引入耦合协调模型,探究新疆县市土地 功能及功能间相互作用程度的时空演变规律,遴选影响区域发展的关键因子,为区域发展提供建议。研究结果表明:(1)新疆县市单元生产功能,生活功能,生态功能及“三生”功能综合评价的时空格局分布差异性显著,均呈现“北高南低”的空间分布特征,以天山北坡城市群为核心高值区。(2)新疆县市“三生”功能耦合协调性总体呈现“北高南低”空间分布态势,县市功能间的耦合协调 关系逐步向好,为区域后续的发展奠定了良好基础。(3)主导产业的选择对于新疆县市功能发展至关重要,同时宏观政策调控有助于功能间的耦合协调性提升,推动县市功能协调有序发展。

  • 乌兹别克斯坦灌溉农业发展及其对生态环境和经济发展的影响

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 乌兹别克斯坦作为中亚干旱区重要的农业大国,由于其独有的气候条件,灌溉是决定其农 业生产的主要控制因素,因此,研究其灌溉农业发展历程对于保障农业生产与自然环境安全具有 重要意义。通过查阅乌兹别克斯坦灌溉农业发展领域的相关文献,结合联合国粮食及农业组织、 联合国数据检索系统等官方网站提供的资料数据,总结灌溉农田面积、人口、主要作物产量及农业 产值等数据的变化规律,阐述了乌兹别克斯坦灌溉农业的发展历程,分析讨论由农业灌溉引起的一系列环境问题及其对社会经济的影响。结果表明:(1)由于气候干旱少雨,乌兹别克斯坦灌溉用水主要来自阿姆河及锡尔河,下游河道径流量及咸海蓄水量持续下降,暴露河床内大量松散沉积 物并导致频繁的沙尘天气。(2)乌兹别克斯坦整体农业灌溉技术较为落后,过度引水使得部分地表径流汇聚在灌区低洼地带,抬升地下水位,最终引发严重的区域土壤盐渍化,故全面推广先进灌排 技术,是该国未来灌溉农业与生态环境健康发展的主要方向。(3)农业生产是乌兹别克斯坦重要的经济来源,对国内生产总值有显著的正向影响。此研究可为干旱区农业发展及水资源管理提供借鉴。

  • 国家公园理念下区域生态旅游资源评价 ——以青海湖与祁连山毗邻区域为例

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 青海湖与祁连山毗邻区域生态旅游资源保护与保护性利用,已成为青海省以国家公园为主 体的自然保护地体系示范省建设的重要组成部分。选取青海湖与祁连山毗邻区域为研究对象,在实际调查的基础上,依据国家公园理念下的资源特性,采用 ArcGIS 空间叠加分析、德尔菲法、AHP (Analytic hierarchy process)层次分析法,对区域内生态旅游资源进行梳理与分类评价。经评价定 级,区域内生态旅游资源级别分为 5 级,游憩资源单体特品级即五级 1 处;优良级 30 处,其中四级 8 处、三级 22 处;普通级 48 处,其中二级 32 处、一级 16 处。研究表明:在国家公园理念下,生态旅游资源评价指标体系要素层权重前三名依次是旅游功能和价值、人文特色、生态环境,评价层选取了国家公园资源属性的因子。可以看出,国家公园首要功能原真性和完整性指标因子是评价指标因 子选取的关键点。旨在为拟建青海湖国家公园功能区划定提供数据支撑,为国土空间禁止开发区 域的生态旅游资源评价提供方法,其研究视角和路径对国家公园理念下游憩资源深度保护和利用 具有借鉴作用。

  • 返贫风险、生计抵御力与规避策略实践 ——祁连山国家级自然保护区内 8 县的调查与分析

    分类: 地球科学 >> 地球科学其他学科 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 农户生产生活中生计风险的识别与应对,一直都是农村经济发展与社会建设进程中需要重 点关注的核心问题。充盈而优质的生计资本决定了农户生计状况,也是农户有效降低其生计脆弱 性、持续增强其生计风险抵御力、快速提升生计恢复力的基础。特别是对于生态脆弱区内的脱贫 户,在脱贫后更容易因生计脆弱性、生计风险而返贫,提高其应对风险冲击的“抗逆力”,增强生计 风险抵御力,将成为生态脆弱区新时期扶贫工作的关键和重点。通过对祁连山国家自然保护区内 农户的生计资本与返贫风险进行调查,并梳理农户风险规避实践;在分析生计风险与生计抵御力 间关系的基础上,从生计抵御力的视角总结不同农户组群的生计特征与风险应对实践之间的对应 关系。研究表明:加强返贫风险抵御力的建设,特别是家庭或更广泛的生计系统(生计网)抵御力 建设,提升生计网的反应能力、适应能力、恢复能力,有助于提升农户规避策略的多样性与有效性, 有助于农户在脱贫摘帽后长期实现持续稳定脱贫。

  • 西北地区投入产出效率的综合测度与时空变化

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 在新时代背景下,提高西北地区社会经济和资源环境的投入产出效率,是推动生态文明建 设、促进高质量转型发展、保障国家长治久安的必然要求和重要途径。为此,构建了投入产出效率综合测度指标体系,并采用 ME-DEA 模型、Mann-Kendall 趋势检验、空间变异系数等方法,对西北地 区 2000—2017 年投入产出效率的时空变化特征进行了分析。结果表明:(1)西北地区投入产出总 体效率由 0.883 波动上升至 0.975,始终在低水平范围内徘徊,而且整体呈不显著提高态势,仅 43.33%的地级行政单元呈显著提高态势。(2)社会经济效率由 0.984 波动上升至 1.079,由低水平过 渡至中等水平,整体呈显著提高态势,但仅 40.00%的地级行政单元呈显著提高态势。(3)资源环境 效率由 0.807 波动上升至 0.897,始终属于低水平,整体呈不显著提高态势,仅 31.67%的地级行政单 元呈显著提高态势。(4)投入产出总体效率长期呈现低水平和中水平广泛分布而中高和高水平零星分布格局,社会经济效率由低水平广泛分布向各类型基本均衡分布的格局演变,资源环境效率 呈现低水平和中水平占绝对主导而中高水平和高水平偶有出现格局。因此,西北地区应建立社会 经济与资源环境的良性交互耦合机制,重点补足资源环境效率短板,同时因地制宜施策,促进投入 产出效率均衡提升。

  • 基于地理探测器的乌鲁木齐市城区扩展及影响因素分析

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 以西北干旱区城市新疆乌鲁木齐市为例,利用 2000、2010 年和 2020 年 3 期 Landsat TM 及 OLI 遥感影像数据,采用随机森林分类方法,基于 250 m×250 m 网格单元,计算每个网格单元中各 类用地面积比率,对 2000—2020 年乌鲁木齐市土地覆被/土地利用(LUCC)空间特征进行分析,运 用地理探测器模型进一步揭示其驱动因素,定量分析评价了 2000—2020 年乌鲁木齐市土地覆被/ 土地利用时空变化特征及响应因素。结果表明:(1)近 20 a 乌鲁木齐市城市化发展迅速,建设用地 面积大幅增加,在 2000 年建成区基础上向北、东北、西北以及东南方向不断蔓延发展,主要以向外 扩张式发展,也存在向城市内部填充式集约增长的趋势。(2)近 20 a 绿地虽出现一定程度的波动, 但总体表现为增长趋势;裸地始终在朝向持续减少的趋势发展。(3)影响乌鲁木齐市土地覆被/土 地利用时空变化分异的主导影响因子是归一化植被指数(NDVI),其贡献率最高;在交互因子探测 结果中,NDVI 与高程共同作用时,呈现双因子增强,解释力最大。监测近 20 a 乌鲁木齐市土地利用的动态变化,可更好地为当前乌鲁木齐城市发展提供借鉴,同时还可对城市未来规划方向进行借鉴。

  • 基于深度学习的寒旱区多时序影像土地利用及变化监测 ——以新疆莫索湾垦区为例

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 针对生态环境脆弱的寒旱区开展地物要素提取以及土地覆盖变化监测研究,对农业规划、 城乡建设、生态环境监测与保护等具有重要意义。借助 2015—2019 年新疆莫索湾垦区 Landsat-8 影像构建数据集,对比 3 种传统方法:最大似然分类(Maximum likelihood classification,MLC)、支持 向量机(Support vector machine,SVM)和随机森林(Random forest,RF)及 5 种语义分割模型:Deep⁃ Labv3+(Xception)、DeepLabv3+(MobileNet)、SegNet(ResNet50)、U-Net(MobileNet)和 PSPNet(Mo⁃ bileNet),选取最优自动化地物提取模型对研究区 1998—2020 年农用地、建筑用地、水体和荒漠 4 种 地物要素进行分类,并运用土地利用转移矩阵和动态度进行定量动态变化分析。结果表明:Deep⁃ Labv3+(Xception)模型可以实现更准确、更高效的地物提取,总体精确度(OA)、Kappa 系数和 F1 值 分别为 96.06%、0.96 和 0.86,其中所选模型的平均交并比(MIoU)较其他模型提升 0.03~0.39。近 23 a,莫索湾垦区的荒漠、农用地和建筑用地三者的土地结构转化较为明显,荒漠总面积减少 15.00%, 农用地总面积增加 12.68%,建筑用地总面积增加 2.53%,水体面积变化较为平稳。地物类型总体转变方向为荒漠向农用地转化、农用地向建筑用地转化。该研究可为深度学习技术应用于中分辨率遥感卫星影像领域中实现土地利用及变化动态监测提供参考。

  • 基于 WRF 模拟的 2017 年帕米尔高原降水特征分析

    分类: 地球科学 >> 大气科学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 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。

  • 基于时频分析的 LSTM 组合模型径流预测

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 针对变化环境下径流时间序列复杂的非线性、非平稳性特征,为提高中长期径流预测的准 确性,运用多种时频分析方法构建组合预报模型以探究适用性。以干旱区典型内陆河玛纳斯河为例,利用经验模态分解(EMD)、变分模态分解(VMD)、离散小波变换(DWT)时频分析方法对径流时间序列进行多尺度分解,得到不同频率和特征的子序列。以前期径流、降水量、气温、大气环流因 子等作为长短期记忆神经网络模型(LSTM)的输入变量,采用随机森林法和 Pearson 相关系数法确 定各子序列的最佳预报因子,基于时频分析方法分别构建 EMD-LSTM、VMD-LSTM、DWT-LSTM 组 合预报模型,通过 LSTM 模型对各子序列进行预测,加和重构获得最终预测结果,并与单一的误差 反向传播神经网络(BP)、极限学习(ELM)、LSTM 模型的预测结果进行对比分析。结果表明:组 合模型 VMD-LSTM 预报误差最小、精度最高,纳什系数保持在 0.9 以上,有效避免了过拟合等问题, 其径流极值预测误差在 15%以内,对径流总体趋势预测和极值的追踪均有良好效果。研究结果可为流域水资源规划与调度提供参考。

  • 山西煤田生态系统服务热(冷)点时空格局

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 基于山西煤田 1986 年和 2015 年的遥感、气象等数据,利用 InVEST(Integrated valuation of ecosystem services and trade offs)模型估算其土壤保持和产水量服务、CASA(Carnegie-Ames-Stanford approach)模型估算植被生产服务、RWEQ(Revised wind erosion equation)模型估算防风固沙服务、 热点分析模拟生态系统服务热(冷)点空间分布格局。结果表明:(1)1986—2015 年,土壤保持服务热点区空间分布整体未发生大变化,冷点区主要从沁水煤田和霍西煤田向河东煤田转移;产水服务热点区在沁水煤田东部增加较明显,冷点区主要在河东煤田南部增多;植被生产服务热点区整 体由沁水煤田南部向东北部移动,冷点区主要从西山煤田和沁水煤田向河东煤田和大同煤田移 动;防风固沙服务热点区整体由西北部向东南部转移,冷点区主要从沁水煤田向霍西煤田和河东煤田转移。(2)1986—2015 年研究区东南部的沁水煤田为多重生态系统服务热点区集中地,属于重 点生态系统服务功能供给区;河东煤田和霍西煤田为多重生态系统服务冷点区变化集中区域。(3)耕地产水量和植被生产服务热点面积占比相对较高,其服务水平强于其他服务;林地和草地的土壤保持服务热点面积最大,属于土壤保持服务高功能区;建设用地的产水服务水平较高。

  • 吉林省西部生态安全格局构建

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 构建生态安全格局能有效保障区域生态安全,尤其是对生态脆弱区环境改善极为重要。以 吉林省西部为研究区,通过生物多样性服务价值、水资源安全、土壤保持、生态需求等 4 项指标识别 生态源地;利用电路理论,结合 Linkage Mapper 工具和 Circuitscape 软件识别生态廊道、夹点区、改善 区,构建吉林省西部的生态安全格局。结果表明:(1)识别 18 块生态源地,占研究区面积 8.57%,主 要分布在现有保护区周边的湿地。(2)构建 38 条关键廊道和 7 条潜在廊道,主要分布在中部和东部 地区,夹点区相对集中于西南部和东部,改善区中建筑用地和盐碱地相对较多。(3)在构建生态源地、廊道、夹点、改善区综合生态安全格局基础上,提出了“一带、两轴、五区、五组团”生态安全格局保护策略。对保障吉林省西部区域安全及经济与生态协调发展提供决策参考。

  • 新疆南疆地区太阳能资源时空分布特征及区划研究

    分类: 地球科学 >> 地理学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 研究基于 1980—2015 年中国区域高时空分辨率地面气象要素驱动数据集(ITPCAS)和 30 个气象观测站点逐月日照资料,运用趋势分析、重标极差分析、小波分析及光热资源评价指标评估方法,对 1980—2015 年新疆南疆地区太阳总辐射时空分布变化规律与太阳能资源做出分析评价;并结合风沙天气频次、人口丰富度、陆路交通可达性等因素构建区域太阳能资源区划分级指标体系,探索南疆地区太阳能资源利用区划。结果表明:新疆南疆地区太阳总辐射有明显的年际变化 特征,总体呈现增长趋势,且每 10~15 a 出现一次波动。太阳能资源南多北少,同纬度相比山区多、 平原少;其中,昆仑山系一带太阳能资源最丰富且较稳定。将全区太阳能资源分为 3 个区:阿克苏、 喀什、和田等地区太阳能资源丰富,利用价值较高且沙尘天气相对较少,为Ⅰ级可利用区,是光电与光生物质能综合利用的最佳区域;塔里木盆地及边缘地带,沙尘天气多且陆路交通可达性一般, 为Ⅱ级可利用区,可在该区域推广应用农业温室、太阳能采暖等;若羌地区为Ⅲ级可利用区,该区受沙尘天气影响较大且人口、基础交通设施条件较差,可大力推进分布式光伏电站和独立微网建设。