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51.
昆仑山北麓地跨昆仑-阿尔金山与塔里木盆地两大地貌单元,毗邻塔克拉玛干沙漠,区内沙源物质丰富,东北风与西北风盛行,风沙活动强烈,沙漠化程度达0.62,是目前我国风沙危害最严重的区域.地貌过程与风沙危害发生的关系,主要表现为风沙地貌过程加强引起风沙危害发生,流水地貌过程减弱使风沙危害加重,人工地貌过程对风沙危害有加强与减弱两方面的作用.区内风沙危害严重与地貌结构,沙漠、砾漠(戈壁)和雅丹面积占73.5%,风沙地貌面积大,沙源物质丰富;气候干旱少雨,荒漠区植被稀疏,风力强劲,风蚀风积强烈;河流稀少,流水地貌过程弱;水资源不足且分布不均,绿洲面积仅占13.49%,绿洲区人工地貌过程对荒漠环境扰动破坏大等有关.针对地貌及其过程对风沙危害的影响及发展趋势,提出了6条防治地貌过程加剧引起风沙危害的措施.  相似文献   
52.
任杰  程嘉强  杨杰  程琳 《水科学进展》2018,29(4):597-606
潜流带是河流生态系统中活跃的生态群落交错区,是地表水和地下水相互作用的重要界面。研究潜流带内存在的潜流交换机制对评估水资源的开发利用以及维持和修复河流生态系统健康有着重要意义。系统介绍了温度示踪方法的一维垂向稳态和瞬态热运移解析模型,梳理归纳了基于温度示踪的时序数据采集方法、信号分析方法和数值方法的相关研究进展,最后对比论述了温度示踪方法的优势和存在的主要问题,同时指出了地下水的多维流动、温度测量的不确定性以及非理想条件对解析模型的影响仍是未来温度示踪方法需要进一步研究的重点。  相似文献   
53.
近年来,由中国地质调查局油气资源调查中心牵头组织实施的“新能源矿产调查工程”,按照工程总体部署,主要开展了黔西、川南、新疆准南、东北三江等地区煤层气地质调查,松辽盆地西斜坡、柴达木盆地北缘油砂、油页岩地质调查,全国液化、气化等特殊用煤资源潜力调查、综合评价与信息系统建设等工作,获取了大量基础数据,取得了川高参1井、杨煤参1井等一系列突破性成果和重要进展,初步掌握了我国煤层气、油页岩、油砂等非常规油气资源以及特殊用煤资源家底。该工程取得的成果在煤层气等行业领域产生重要影响,提振了煤层气勘探开发信心,推动了科技创新与地质调查深度融合,促进了非常规油气学科的发展。  相似文献   
54.
Heavy aeolian deposition is one of the most threatening natural hazards to oases in arid areas. How an oasis affects aeolian deposition is tightly related to the local ecological environments. To examine the effects of oasis on aeolian deposition under different weather conditions, monthly aeolian deposition from April 2008 to March 2009 and additional samples during dust storms in April and May 2008 were collected at four sites along the Qira oasis. The monthly ADRs (aeolian deposition rates) varied greatly with seasons and sites, ranging from 19.4 to 421.2 g/m2/month and averaging 198.8 g/m2/month. Aeolian deposition in the oasis was composed dominantly of sand and silt. Based on the variations of ADRs from the four sites, it can be found that the oasis exhibits two different effects on aeolian deposition under different weather conditions. During dust storms, the oasis demonstrates a significantly shielding effect due to the obstruction of the oasis-protection systems, resulting in most aeolian particles being deposited at the windward side of the oasis. While during non-dust storm periods with weak winds, the oasis exhibits an “attracting” effect on aeolian deposition, leading to a higher ADR inside the oasis. Owing to the annual ADR is dominated by the non-dust storm ADR in Qira, the oasis seems to become an important aeolian deposition area caused by the “attracting” effect of the oasis.  相似文献   
55.
以北票开发区为研究对象,通过对不同工业行业进行划分,建立不同行业工业用地土地集约利用水平评价指标体系,应用多因素综合评价模型对开发区内不同行业工业用地集约利用水平进行了测算,揭示其集约利用水平及其差异性,研究结果表明:北票开发区整体工业用地集约利用水平较高,其中纺织业、服装及其他纤维制品制造业和化学原料及化学制品制造业用地集约水平最高,而饮料制造业用地集约利用水平最低。  相似文献   
56.
土地退化对减缓和适应气候变化有重要影响,并威胁到全世界的可持续发展,造成一系列社会、经济和生态问题,是目前全球面临的最大环境挑战之一。基于2001—2020年埃塞俄比亚的归一化植被指数(NDVI)、气象数据及土地覆盖数据,通过CASA模型计算获得植被净初级生产力(NPP)和水分利用效率(WUE),并使用Sen+MK趋势分析方法得到土地退化及其恢复趋势,同时采用多元逐步回归方法分析了土地退化及恢复的驱动因素。结果表明:2001—2020年,埃塞俄比亚土地退化整体呈现恢复趋势,恢复区域占全国面积的34.51%,主要分布在埃塞俄比亚西部以及索马里州;退化区域仅占全国面积的1.63%,主要分布在首都亚的斯亚贝巴。土地退化及恢复的主要驱动因素是人为与气候共同因素和人为单因素。土地退化的主要因素为人口的快速增长以及城市的扩张,土地恢复则与20年来实施的森林景观恢复以及可持续土地管理措施和政策有关。  相似文献   
57.
58.
In terms of the research on groundwater–surface water heat-tracing methods, investigation of the interactions within the compound system of the groundwater–surface water–hyporheic zone can effectively reveal the relevant physicochemical processes and microbial properties. The evaluation of these properties represents a key component in qualitative and quantitative research on groundwater–surface water interactions. Therefore, this paper reviews the research results on groundwater–surface water interactions achieved by related researchers using heat as a natural tracer over the last decade. In connection with the application of heat-tracing theory to the basic principles of hyporheic exchange between groundwater and surface water, research on groundwater–surface water interaction through one-dimensional steady-state and transient-state heat transport analytical models, techniques to collect and analyze temperature time series data, and numerical simulation technology is reviewed. In addition, directions for future research using groundwater–surface water heat-tracing methods are suggested. First, hypothetical, difficult temperature boundary and hydrogeological conditions require further research. Second, hydrodynamic exchange capacity and the processes of heat exchange and solute concentration exchange in the hyporheic zone alongside riverbeds should be appropriately and accurately measured under multi-scale influences. Third, the overall study of the heat transport process inside the hyporheic zone induced by complex riverbed forms should be performed, and the response mechanism of riverbed hyporheic exchanges driven by riverbed form, the hydrodynamic force of surface water, and sediment permeability should be revealed. The objectives and goals of this paper are to encourage scholars interested in analyzing groundwater–surface water interactions using heat as a tracer to creatively solve practical problems and to improve the ecological functions of river aquatic habitats through new research results.  相似文献   
59.
Landscape characteristics influence meteorological factors, thus affect the occurrence and nature of dust storm events. The present study investigates the spatiotemporal characteristics of six meteorological factors (wind velocity, wind direction, air temperature, relative humidity (RH), photo synthetically active radiation (PAR), and solar radiation) over different landscape types (shifting-sand frontier, semi-fixed sandy land, fixed sandy land, and the inner region of an oasis) before and after dust storms during four typical dust storm events in an oasis-desert ecotone in Cele, Xinjiang, China. The results show that the average wind velocity decreased significantly from the shifting-sand frontier to the inner oasis, which was mainly attributable to the vegetation coverage. Before the dust storm events, there were obvious differences in air temperature and RH either in the horizontal or vertical direction over the different landscape types. However, these factors were very similar during and following the dust storm events. PAR and solar radiation were significantly reduced during the dust storm events and the subsequent sand-blowing and floating-dust conditions. This effect was much stronger than during similar weather conditions without dust storm events such as sand-blowing and overcast and/or rainy days. Additionally, the variation in the meteorological factors among the different landscapes was also affected by the prevailing wind direction during the dust storm events. However, the landscape type slightly changed the prevailing wind direction, with the greatest dispersion distribution of wind direction in the inner oasis. The findings of this study are helpful for understanding the function of landscape types in the occurrence of dust storms, as well as for providing a theoretical basis for prevention of dust storms.  相似文献   
60.
南京地区雷暴活动强度潜势预报   总被引:2,自引:0,他引:2  
利用江苏省2008、2009和2010年6 8月闪电定位资料对雷暴活动的强度进行了分级,并使用同一时段的探空资料计算了47个代表南京地区 环境层结特征的对流参数,利用其与雷暴活动强度的相关性选取预报因子.在此基础上,采用Bayes分类法和Logistic 回川归分析法,结合逐步选择法进一步筛选预报因子,分别建立了两种雷暴强度的预报模型.通过检验独立样本对比分析两种模型的预报效果,结果表明,Logistic回归分析法的Hedike技巧评分为0.396,并能识别出30%的强雷暴,而Bayes分类法的Hedike技巧评分为0.370,只能识别出5%的强雷暴.Logistic回归分析法对雷暴强度的潜势预报具有较好的指示意义.进一步分析进入预报模型的9个对流参数,表明雷暴活动越强时,低层空气越暖湿,中层空气越干冷,高低层的风切变越大.  相似文献   
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