Variations in glacier volume and snow cover and their impact on lake storage in the Paiku Co Basin,in the Central Himalayas     

Xingxing Zhang  Rui Wang  Zhijun Yao  Zhaofei Liu 《水文研究》2020,34(8):1920-1933

Glaciers and snow cover are important constituents of the surface of the Tibetan Plateau. The responses of these phenomena to global environmental changes are sensitive, rapid and intensive due to the high altitudes and arid cold climate of the Tibetan Plateau. Based on multisource remote sensing data, including Landsat images, MOD10A2 snow product, ICESat, Cryosat-2 altimetry data and long-term ground climate observations, we analysed the dynamic changes of glaciers, snow melting and lake in the Paiku Co basin using extraction methods for glaciers and lake, the degree-day model and the ice and lake volume method. The interaction among the climate, ice-snow and the hydrological elements in Paiku Co is revealed. From 2000 to 2018, the basin tended to be drier, and rainfall decreased at a rate of −3.07 mm/a. The seasonal temperature difference in the basin increased, the maximum temperature increased at a rate of 0.02°C/a and the minimum temperature decreased at a rate of −0.06°C/a, which accelerated the melting from glaciers and snow at rates of 0.55 × 10⁷ m³/a and 0.29 × 10⁷ m³/a, respectively. The rate of contribution to the lake from rainfall, snow and glacier melted water was 55.6, 27.7 and 16.7%, respectively. In the past 18 years, the warmer and drier climate has caused the lake to shrink. The water level of the lake continued to decline at a rate of −0.02 m/a, and the lake water volume decreased by 4.85 × 10⁸ m³ at a rate of −0.27 × 10⁸ m³/a from 2000 to 2018. This evaluation is important for understanding how the snow and ice melting in the central Himalayas affect the regional water cycle.  相似文献   

南黄海物理-生物地球化学过程的时空异质性及内在关联和机制   总被引：2，自引：0，他引：2  

韦钦胜  王保栋  傅明珠  孙俊川  姚庆祯  辛明  于志刚 《海洋学报(英文版)》2020,39(10):11-26

研究多重物理过程控制下陆架边缘海生物地球化学过程的时空异质性及其生态响应，对于深入认识海洋生态系统具有重要的意义。基于相关历史观测资料和卫星遥感海表温度，本文综合分析了南黄海物理-生物地球化学过程的时空变化和空间异质性特征，探讨了该海域内部典型地理单元之间的内在关联和机制。结果显示，冷季沿岸流南向输送和暖季锋面上升流垂向输运的季节性交替是影响石岛外海与海州湾外侧海域生物地球化学和初级生产的重要物理过程。夏季苏北沿岸水的东北向扩展可形成浒苔离岸/跨区域输送的动力驱动。暖季水体层化显著影响着南黄海中部冷水团海域的生物地球化学过程，春至秋季冷水团海域底层水体中的营养盐逐渐累积，形成了营养盐的重要贮库；层化季节黄海冷水团边界锋区上升流系统的存在使得南黄海叶绿素a和初级生产力高值区位置同海表低温涌升流区总体相一致。冷季南黄海西部南下的冷水与中部北向入侵的暖水共同导致了“S”型锋面的形成；暖季黄海冷水团边界锋区的上升流系统是连接层化海域和近岸区的纽带，可实现对冷水团内部营养盐的提取，从而将冷水团内部和边界区的生物地球化学过程形成有机连接，并在成山角-石岛外海、海州湾外侧、苏北浅滩东部形成三个典型的物理-生物地球化学相互作用区。本研究细化和整合了南黄海区域海洋学研究，揭示了该海域物理-生物地球化学过程的空间异质性特征和不同地理单元之间的关联性及机制，获得了对南黄海水文-生物地球化学-生态过程的综合、系统认知。  相似文献   

南海北部海域油气勘探保障建设选址适宜性研究     

武二亮  陈浩东  刘裕光  安永宁 《海岸工程》2020,39(4):256-262

为分析南海北部海域油气勘探保障建设选址的适宜性,在广泛研究备选区特征资料的基础上,基于层次分析法(Analytic Hierarchy Process, AHP)原理,以自然环境因素、开发环境因素、基础设施与投资情况以及其他因素作为一级评判准则,建立了包括12项二级评判准则的递进层次结构模型,并以永兴岛、赵述岛和晋卿岛作为3个假定备选区,来验证分析评价模型的有效性和可靠性。AHP评判结果显示,3个备选区的整体优劣指数依次为0.587 1, 0.212 1, 0.200 8;AHP模型的一致性比例CR值为0.020 3。通过分析和筛选影响远海油气勘探保障建设的选址因子,构建基于AHP原理的选址评价模型,可用于分析评价南海北部岛礁油气勘探保障建设选址的适宜性。  相似文献   

Ensemble modelling of ice cover for a reservoir affected by pumped‐storage operation and climate change     

Ulrike Gabriele Kobler  Martin Schmid 《水文研究》2019,33(20):2676-2690

Ensemble modelling was used to assess the robustness of projected impacts of pumped‐storage (PS) operation and climate change on reservoir ice cover. To this end, three one‐dimensional and a two‐dimensional laterally averaged hydrodynamic model were set up. For the latter, the strength of the impacts with increasing distance from the dam was also investigated. Climate change effects were simulated by forcing the models with 150 years of synthetic meteorological time series created with a weather generator based on available air temperature scenarios for Switzerland. Future climate by the end of the 21^st century was projected to shorten the ice‐covered period by ~2 months and decrease ice thicknesses by ~13 cm. Under current climate conditions, the ice cover would already be affected by extended PS operation. For example, the average probability of ice coverage on a specific day was projected to decrease by ~13% for current climate and could further be reduced from ~45% to ~10% for future climate. Overall, the results of all models were consistent. Although the number of winters without ice cover was projected to increase for all one‐dimensional models, studying individual segments of the two‐dimensional model showed that the impact was pronounced for segments close to the PS intake/outlet. In summary, the reservoir's ice cover is expected to partially vanish with higher probability of open water conditions closer to the PS intake/outlet.  相似文献   

2000年以来青藏高原湖泊面积变化与气候要素的响应关系   总被引：1，自引：0，他引：1  

闾利  张廷斌  易桂花  苗加庆  李景吉  别小娟  黄祥麟 《湖泊科学》2019,31(2):573-589

青藏高原星罗密布的湖泊对气候变化十分敏感，在自然界水循环和水平衡中发挥着重要作用.以MODIS MOD09A1和SRTM DEM为数据源，提取了2000-2016年青藏高原丰水期面积大于50 km²的湖泊边界，从内外流分区、湖泊主要补给来源和湖水矿化度三个方面对2000年以来湖泊面积变化进行分析，并结合青藏高原近36年气象数据，根据气象要素变化趋势分区，初步探讨青藏高原湖泊面积变化与气候要素的关系.结果表明：青藏高原面积大于50 km²的138个湖泊整体扩张趋势显著，总面积增加2340.67 km²，增长率为235.52 km²/a.其中，扩张型湖泊占67.39%，萎缩型湖泊占12.32%，稳定型湖泊占20.29%.内流湖扩张趋势显著，外流湖扩张趋势较明显；以冰雪融水为主要补给来源的湖泊整体扩张趋势明显，以地表径流和河流补给为主要补给源的湖泊也呈扩张趋势；盐湖和咸水湖以扩张为主，淡水湖的扩张、萎缩和稳定三种类型较均衡.在青藏高原气候暖湿化方向发展背景下，湖泊面积变化与气候要素具有显著的区域相关性.气温和降水变化趋势分区结果表明，气温增加、降水增加强趋势的高原Ⅰ区湖泊扩张程度（78.18%）依次大于气温降低、降水量呈增加趋势的Ⅴ区（66.67%），气温、降水量呈增加趋势的Ⅱ区（60.78%），气温呈降低、降水量呈增加强趋势的Ⅳ区（58.83%）和气温呈增加、降水量呈减少趋势的Ⅲ区（50.00%）.湖泊面积变化对气候变化响应研究表明，升温引起的冰雪融水补给对Ⅰ区、Ⅱ区和Ⅲ区湖泊面积扩张的影响显著，加之降水量的增加，湖泊扩张速率明显；Ⅳ区和Ⅴ区湖泊面积扩张主要受降水量增加影响显著.整体而言，气温主要影响以冰雪融水为主要补给来源的湖泊，降水量主要影响以降水和地表径流为主要补给来源的湖泊.  相似文献   

城市湖泊春季绿藻水华特征及其影响因素——以宁波月湖为例     

周卢茜  裘钱玲琳  唐剑锋  徐耀阳  潘军标  王小德 《湖泊科学》2019,31(4):1023-1034

城市湖泊富营养化问题日趋严峻，以往对水华的研究多集中于大型自然淡水湖库，而对小型城市浅水湖泊的水华动态相对较少.以宁波月湖为研究对象，探讨水华暴发期间浮游植物变化特征及与影响因子之间的关系，以期判别影响城市湖泊水华的主控因子.月湖水华期间营养盐水平处于中富营养至极端富营养之间，此次共检出浮游植物8门61属，藻种组成以绿藻门（51.79%）和硅藻门（21.43%）为主，各点位浮游植物生长主要受水温、光照驱动，经历了隐藻门→硅藻门→绿藻门→蓝藻门的演替.水华种为雷氏衣藻（Chlamydomonas reinhardtii），总藻密度最高达到1.55×10⁸ cells/L，水华暴发后各点位衣藻属比例升高（最高达到81.10%），群落结构呈现单一化特征.通过Pearson相关性分析和RDA分析发现衣藻属生长与水温、pH、总磷浓度均呈显著正相关，春季气温回升、天气持续晴好，城市浅水湖泊高营养盐负荷、水体流动性差等特点为带鞭毛的衣藻属提供了适宜的生存条件，在环境条件均适宜的情况下拥有最大生长潜力的衣藻属在营养盐、光照等竞争中生长速率明显优于其他藻种，从而发生绿藻水华.  相似文献   

帕隆藏布流域冰湖变化及危险性评估     

刘娟  姚晓军  高永鹏  祁苗苗  段红玉  张大弘 《湖泊科学》2019,31(4):1132-1143

冰湖作为区域气候变化的灵敏指示器和主要冰川灾害的启动器，认识其空间分布及变化特征对探讨冰湖对气候变化的响应规律及冰湖溃决危险性评估具有重要意义.基于1968-1980年地形图数据和1994-2016年Landsat TM/OLI遥感影像资料，综合利用RS、GIS技术和数理统计方法分析帕隆藏布流域面积≥ 0.01 km²冰湖时空分布及其动态变化，并对潜在危险性冰湖进行判别和评估.结果表明：2016年帕隆藏布流域共有冰湖351个，面积50.48 km²，且面积和数量分别以面积>1 km²和面积<0.1 km²的冰湖为主，这些冰湖主要分布于海拔2800~5400 m之间.近50年来帕隆藏布流域冰湖总体呈数量增多、面积增加态势；海拔<3000 m的冰湖相对稳定，而海拔>4500 m的冰湖数量和面积增加则相对迅速.近50年间帕隆藏布流域冰川面积减少591.34 km²，气候变暖导致的冰川末端退缩和冰川融水增加为冰湖形成和扩张提供了发育空间和物质来源.切毛措、光谢错等9个冰湖为潜在危险性冰湖，预计未来一段时间内帕隆藏布流域冰湖溃决可能处于活跃阶段，其形成和暴发也将更加频繁.  相似文献   

太湖不同生态型湖区枝角类组成和丰度长期变化的差异性     

程龙娟  姚书春  薛滨  李玲玲  刘金亮 《湖泊科学》2019,31(6):1670-1684

枝角类作为淡水湖泊生态系统中的初级消费者之一,对生存环境的改变极为敏感.本文分析了太湖西、中和东部等湖区的钻孔沉积物、表层沉积物以及春夏秋季活体枝角类的组成与丰度.结果表明:活体枝角类组成以象鼻溞(Bosmina spp.)为优势种,秋季枝角类属种数量最多.太湖不同生态型湖区表层沉积物枝角类组成均以象鼻溞为优势种,其中西部与中心湖区的枝角类组成与丰度较为相似,种类单一,枝角类绝对丰度高;东部湖区枝角类属种较为丰富,绝对丰度低,优势种由浮游种象鼻溞以及沿岸种圆形盘肠溞(Chydorus sphaericus sl)和西方笔纹溞(Graptoleberis testudinaria)等种属构成.百年以来,太湖枝角类组成与丰度随着营养水平增加而改变,富营养指示种(Bosmina longirostris)丰度的增加与贫营养指示种(Bosmina longispina)丰度的下降,响应了湖区生态环境的演变过程.1970s末期,太湖西部与中心湖区在进入富营养化阶段,枝角类组成单一,象鼻溞占有绝对优势,与东部湖区相比,沿岸种、底栖种稀少.东部湖区在1960s以后,枝角类属种数量增加,但丰度下降,响应了1960s以来该区域营养水平提高、沉水植被生物量增加以及沼泽化加剧的环境过程.  相似文献   

A method for evaluating the longitudinal functional connectivity of a river–lake–marsh system and its application in China     

Yeling Liu  Baoshan Cui  Jizeng Du  Qing Wang  Shuling Yu  Wei Yang 《水文研究》2020,34(26):5278-5297

The longitudinal functional connectivity of a river–lake–marsh system (RLMS) refers to the actual water-mediated transport of material from upstream to downstream areas along a spatial gradient and is fundamental to understand hydrological and biogeochemical cycles. However, due to a lack of consensus on appropriate data and methods, the quantification of connectivity is still a challenge, especially at the catchment scale. We developed a new method to evaluate longitudinal functional connectivity based on fluxes of materials (water, sediment, and chemicals) along a RLMS. The calculation of fluxes is based on the longitudinal pattern of terrain gradient, which influences transport efficiency, and on contributions from hillslopes, which set the initial spatial template of material loading to the RLMS. We evaluate the contributions from hillslopes to RLMS based on a new modified version of the index of sediment connectivity (IC) proposed by Borselli et al. (2008) and revised by Chartin et al. (2017).We applied this method to the Baiyangdian Basin covering an area of 3.4 × 10⁴ km² in China and quantified longitudinal functional connectivity during normal, wet, and dry periods(April, July and December) in year 2016. We found that areas with good structural connectivity exhibited poor functional connectivity during the normal and dry periods. Modelling testing with discharge data from hydrological stations and measured chemicals from Baiyangdian Lake was satisfactory in test periods. We conclude that public data and Digital Elevation Model-derived information can be used to reliably map the longitudinal functional connectivity of RLMSs. The proposed method provides a useful tool for monitoring and restoring the longitudinal functional connectivity of RLMSs and our results indicate that efforts aimed at restoring functional connectivity in RLMSs should take into account landscape patterns that can greatly influence fluxes in the watershed.  相似文献   

汶川M_W7.9地震起始破裂断层几何结构          下载免费PDF全文

宫猛  徐锡伟  李康 《地球物理学报》2020,63(3):1224-1234

本文收集使用紫坪铺水库台网记录到的汶川地震主震P波波形资料,利用P波反投影叠加法获取了2008年5月12日汶川M_W7.9地震起始破裂的时空演化过程.通过分析本次大地震起始破裂阶段(0～1s)破裂点在三维空间内的分布特征,确定了本次大地震起始破裂位置及起始破裂断层几何结构模型.得到以下结果:汶川地震起始破裂点位于31.013±0.002°N、103.392±0.002°E,震源深度为8.2±0.4km,发震时刻为2008年5月12日14∶27∶58.80±0.4.汶川地震起始破裂的最佳断层面走向为NE48°,倾向NW35°,起始阶段破裂的深度范围为地下7.5～9km.  相似文献