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1.
基于三江源典型区(索加-曲麻河自然保护区)1977—2007年的遥感影像解译数据和统计资料,采用偏相关分析筛选与湿地变化显著相关的因子,通过主成分分析、灰色关联度分析驱动因子对湿地变化的贡献率大小。结果表明:近30年来湿地变化的驱动因素主要为气候因素,其中以年平均气温、年蒸发量和年平均相对湿度为重要影响因子。通过计算主要影响因子对湿地变化的灰色关联度,认为年平均相对湿度和年蒸发量对河流湿地变化的贡献率最大,年平均温度与湖泊湿地、沼泽湿地和河滩地动态变化的关联程度最高。  相似文献   

2.
乔治  贺曈  卢应爽  孙宗耀  徐新良  杨俊 《地理研究》2022,41(7):1932-1947
近年来全球气候变化已经影响到人类生活的所有地区,气候系统变化的规模和现状是数千年来前所未有的。与此同时,中国城镇化进程显著加快,尤其以城市建设用地扩张主导的土地城镇化最为突出,导致城市热环境脆弱性加剧。已有研究探索了特定类型土地利用变化对于城市热环境的影响,但忽视了全球气候变化背景下自然气候和人类活动共同作用城市热环境变化的双重过程。因此,本研究提出一种基于土地利用类型的城市热环境变化贡献度算法,旨在厘清自然气候(表征为土地利用平均温度变化)和人类活动(表征为土地利用类型转变)对于区域热环境变化的单独贡献。本研究使用中分辨率成像光谱仪(Moderate-Resolution Imaging Spectroradiometer,MODIS)地表温度及发射率数据,定量计算2005—2020年四季和昼夜京津冀城市群各城市土地利用类型平均温度和面积变化对于城市热环境变化的分别贡献。该算法计算各城市四季和昼夜地表温度变化与MODIS LST产品误差在1 K以内。2005—2020年各城市地表平均温度大多数呈增长态势,其中冬季白天增温幅度最高。耕地、城市建设用地和农村居民点对城市热环境变化的贡献度较其他土地利用类型突出。京津冀城市群中各城市人类活动对城市热环境变化的单位贡献强度远高于自然气候(4.03~648.07倍),而人类活动的贡献总量(-0.25~0.92 K)低于自然气候(-2.40~6.50 K)。研究结果对于京津冀城市群空间协同发展和适应及减缓气候变化等具有重要的科学意义和实践价值。  相似文献   

3.
回顾过去2000年中国气候变化的研究历史,总结了本领域在最近10年的新成果,并对未来研究动向进行了展望。主要内容包括:代用证据采集、过去2000年温度序列重建与冷暖期辨识、降水及干湿序列重建与变化特征分析、过去千年气候变化模拟与机制诊断、历史气候变化影响分析等。主要进展体现在:加密了中国气候变化代用资料的空间覆盖度,提升了2000年气候变化序列重建、资料分析和影响辨识等研究的定量化程度,深化了对中国过去2000年气候在年代—百年尺度的变化特征及其形成机制与影响的认识。为进一步揭示地球系统的变化规律,特别是更深入认识中国气候的时空变化规律提供了更好的基础。  相似文献   

4.
Benito Giordano 《Area》2001,33(1):27-37
The Lega Nord (Northern League) regionalist party, which has risen to prominence in Italy in recent years, has a specific geographical focus to its political project. This is premised essentially upon the protection of Northern Italian economic (and cultural) interests, however, this geographical focus has been modified during the Lega Nord's relatively short political history. This paper explores the reasons why there have been various shifts in geographical emphasis in the party's political rhetoric as well as the ways in which support for the Lega Nord has changed (or not) as a result of these changes. Interestingly, the latest shift in the Lega Nord's rhetoric has seen the party attempting to construct (and invent) a geography and an ethnicity for a place it calls 'Padania' (which roughly corresponds to North and Central Italy) that has never existed administratively or historically. However, as the paper argues, the Lega Nord's attempts to create a 'Padanian' political identity, have not been matched by any significant changes in its electoral geography.  相似文献   

5.
大渡河上游地区土地利用动态模拟分析   总被引:50,自引:9,他引:41  
基于1967、1987和2000年三期遥感数据和1:25万数字高程模型,通过Logistic逐步回归分析,在地形、海拔、水系、道路交通、城镇和居民点分布等多种自然地理和社会经济因素中,筛选出不同时期对大渡河上游地区主要土地利用类型空间分布及其变化具有决定作用的驱动因子,并生成相应的土地利用空间分布概率适宜图,然后采用CLUE-S模型,模拟分析了1987年和2000年两个时点上金川、壤塘和马尔康三县18665 km2范围内的土地利用状况。用当年的现状图检验对比的结果表明,模拟取得了较为理想的结果,Kappa值分别达到0.86和0.89。在此基础上,针对三种政策情景,应用相同模型模拟预测了研究地区2010年时的土地利用时空变化。  相似文献   

6.
黄河流域天然径流量突变性与周期性特征   总被引:22,自引:1,他引:22  
杨志峰  李春晖 《山地学报》2004,22(2):140-146
突变性和周期性是水文时间序列的两个重要特征。黄河流域面积广阔,各区域水文水资源系统演变规律各不相同,它们的突变和周期变化及其形成的物理机制遍异,因此系统分析各区域水资源突变性和周期性特征及其影响机制具有重要意义。把黄河流域划分为15个区域,计算出各区域1951—1998年的年天然径流量系列。利用Mann-Kendall非参数检验方法检测黄河流域各区域年天然径流量的突变年份,结果表明各区域的突变年份不完全一致,主要在1953—1955年、1979—1983年、1991—1993年等发生了突变,这些突变与北半球气候突变具有一致性,且由于下垫面改变、人类活动等影响而复杂化。利用Morlet小波分析各区域年天然径流量的变化周期,发现主要存在3~4a、7~9a、11a的周期,形成这些周期的物理因子有太阳黑子、海—气相互作用和下垫面因素等。通过分析黄河流域主要产流区不同时段小波系数变化,发现20世纪80年代之后年径流量主要以短周期变化。  相似文献   

7.
青海湖地区生态系统服务价值变化分析   总被引:4,自引:0,他引:4  
采用生态系统服务估值、Matlab7.0 多元线性回归分析和敏感性分析等研究方法, 定量分析了生态系统服务价值的变化及其与气候、GDP、个人储蓄、城市化水平等驱动因子之间的相关性和敏感性, 以识别影响青海湖生态环境的主要影响因素, 以期为该区域生态保护调控和管理提供依据。研究结果表明:①2000-2008 年青海湖地区生态系统服务价值平均为119.226 亿元, 2008 年比2000 年下降3.98%;②2000-2008 年生态系统服务价值变化与气温和社会经济发展因素存在显著的负相关, 对气温、GDP和城镇化率的弹性系数分别为0.896、0.249 和0.2988;③2000-2008 年, 生态系统服务价值变化对城市化率和气温具有很大的敏感性, 敏感性系数分别为4.979 和1.712。研究表明, 青海湖地区的生态系统服务下降是气候暖干化和经济发展的综合作用结果。青海湖地区应该关注农牧民生计, 实施生态补偿机制以实现可持续的生态保护战略。  相似文献   

8.
b
From a study of the sunspot cycle influence on the lunar ( L ) and solar ( S ) daily geomagnetic variations, Malin, Cecere & Palumbo have suggested that the electric currents responsible for these variations do not flow in the E -region as has hitherto been accepted. Indeed they suggested that the L current may even flow in the F 2 region. The consequences of such a suggestion are considered and it is shown that an L current in the F -region is highly unlikely from the dynamical point of view. The evidence for E -region currents is presented and it is suggested that the variation of E -region electron density used by Malin et al . to indicate conductivity changes in that region may not be a reliable indicator of such changes.  相似文献   

9.
We investigate the response of the Nordic seas-Arctic Ocean system to surface freshwater flux anomalies that we regard as typical for long-term atmospheric variability. We employ response experiments with a coupled sea ice-ocean model where we introduce a surface freshwater flux anomaly (A) over the Norwegian Sea and (B) in the Laptev Sea. Case A offers an explanation for the intermediate depth salinity changes observed in the Amundsen Basin. The signal observed there belongs to an original perturbation that, according to the model, occurred around a decade earlier. Salinity fluctuations in the Laptev Sea could play a role in changes in the near surface salinity in the Amundsen Basin.  相似文献   

10.
There is plenty of forests in Northeast China which contributes a lot to the conservation of water and land resources, produces timber products, and provides habitats for a huge number of wild animals and plants. With changes of socio-economic factors as well as the geophysical conditions, there are dramatic changes on the spatial patterns of forest area. In this sense, it is of great significance to shed light on the dynamics of forest area changes to find the underlining reasons for shaping the changing patterns of forest area in Northeast China. To explore the dynamics of forest area change in Northeast China, an econometric model is developed which is composed of three equations identifying forestry production, conversion from open forest to closed forest and conversion from other land uses to closed forest so as to explore the impacts on the forest area changes from demographic, social, economic, location and geophysical factors. On this basis, we employ the Dynamics of Land System (DLS) model to simulate land-use conversions between forest area and non-forest cover and the land-use conversions within the sub-classes of forest area for the period 2000–2020 under business as usual scenario, environmental protection scenario and economic growth scenario. The simulation results show that forest area will expand continuously and there exist various kinds of changing patterns for the sub-classes of forest area, for example, closed forest will expand continuously and open forest and shrub will decrease a little bit, while area of other forest will keep intact. The research results provide meaningful decision-making information for conserving and exploiting the forest resources and making out the planning for forestry production in the Northeast China region.  相似文献   

11.
中国东北地区林地面积变化的动态模拟   总被引:1,自引:0,他引:1  
There is plenty of forests in Northeast China which contributes a lot to the conservation of water and land resources, produces timber products, and provides habitats for a huge number of wild animals and plants. With changes of socio-economic factors as well as the geophysical conditions, there are dramatic changes on the spatial patterns of forest area. In this sense, it is of great significance to shed light on the dynamics of forest area changes to find the underlining reasons for shaping the changing patterns of forest area in Northeast China. To explore the dynamics of forest area change in Northeast China, an econometric model is developed which is composed of three equations identifying forestry production, conversion from open forest to closed forest and conversion from other land uses to closed forest so as to explore the impacts on the forest area changes from demographic, social, economic, location and geophysical factors. On this basis, we employ the Dynamics of Land System (DLS) model to simulate land-use conversions between forest area and non-forest cover and the land-use conversions within the sub-classes of forest area for the period 2000–2020 under business as usual scenario, environmental protection scenario and economic growth scenario. The simulation results show that forest area will expand continuously and there exist various kinds of changing patterns for the sub-classes of forest area, for example, closed forest will expand continuously and open forest and shrub will decrease a little bit, while area of other forest will keep intact. The research results provide meaningful decision-making information for conserving and exploiting the forest resources and making out the planning for forestry production in the Northeast China region.  相似文献   

12.
珠江三角洲网河区水文与地貌特征变异及其成因   总被引:37,自引:1,他引:37  
陈晓宏  陈永勤 《地理学报》2002,57(4):429-436
采用珠江三角洲网河区数十年来的人类活动和水文特征资料,通过分析人类活动的水文响应特征,发现该地区近10年多来水文情势发生了显著异变。主要表现在河道人工采砂以及大洪水冲刷导致河床下芬,部分断面水位-流量关系异变。部分河段冲淤特征倒转,汊河分水分沙比发生变化。围垦,臾,码头建设以及水闸的不合理调度使得水量集中,蓄滞洪能力减小,河道流量增加。三角洲上部河床剧烈下切,汇流速度加快;而口门多呈淤只状态,加之海平面上升,潮流顶托阻水,三角洲腹地水位抬升,洪涝威胁加剧。剧烈人类活动是珠江三角洲网河区水文与地貌特征变异的直接原因。  相似文献   

13.
Based on analyzing long-term (1968–2010) national monitoring data from Rosgidromet and other agencies as well as on research results for the Lower-Don and Kuban’ river basins, we identified observation posts on water bodies with a stably high pollution level and gave a characterization of the spatiotemporal tendencies of its changes. Long-term changes in water quality are exemplified by an alternation of periods of increasing and declining pollution; its level showed a decrease from the period 1980–1990 to the end of the last decade.  相似文献   

14.
目前,关于里海的两个主要问题是水位变化及其生态条件。历史上,里海的海水入侵和衰退对该区域的生活和生产有很大影响。应用地质数据、历史数据和考古数据,以及观测数据,本文对地质历史时期里海水位的变化、年度和季度变化以及短期的波动进行了研究。文章对解释里海水位波动的两种不同的方法进行了论述,并认为里海水位变化是受地质、水文气候和水量平衡以及人类活动等因素的影响的多级过程,其中主要影响因素为水文气候的变化。  相似文献   

15.
基于卫星遥感和再分析数据的青藏高原土壤湿度数据评估   总被引:5,自引:1,他引:4  
范科科  张强  史培军  孙鹏  余慧倩 《地理学报》2018,73(9):1778-1791
土壤水是地表与大气在水热交换方面的关键纽带,是关键水循环要素,更是地表产汇流过程的关键控制因子。青藏高原是地球第三极,也是亚洲水塔,探讨青藏高原土壤水变化对于探讨青藏高原热力学特征变化及其对东亚乃至全球气候变化的影响具有重要意义,而获取高精度长序列大尺度土壤水数据集则是其关键。本文利用青藏高原100个土壤水站点观测数据,从多空间尺度(0.25°×0.25°,0.5°×0.5°,1°×1°)、多时间段(冻结和融化期)等角度,采用多评价指标(R、RMSE、Bias),对多套遥感反演和同化数据(ECV、ERA-Interim、MERRA、Noah)进行全面评估。结果表明:① 除ERA外,其他数据均能反映青藏高原土壤水变化,且与降水量变化一致。而在那曲地区,遥感反演和同化数据均明显低估实测土壤水含量。从空间分布来看,MERRA和Noah与植被指数最为一致,可很好地反映土壤水空间变化特征;② 青藏高原大部分地区土壤水变化主要受降水影响,其中青藏高原西部边缘与喜马拉雅地区土壤水变化则受冰雪融水和降水的共同影响;③ 除阿里地区外,大部分遥感反演和同化数据在融化期与实测土壤水相关性高于冻结期,其中在那曲地区,遥感反演和同化数据均高估冻结期土壤含水量,却低估融化期土壤含水量。另外,遥感反演和同化数据对中大空间尺度土壤水的估计要好于对小空间尺度土壤水的估计。本研究为青藏高原土壤水研究的数据集选择提供重要理论依据。  相似文献   

16.
西北干旱区黑河下游植被覆盖变化研究综述   总被引:6,自引:0,他引:6  
植被作为干旱区敏感的环境要素, 能直观反映自然环境状况, 任何植被覆盖变化都可揭 示区域环境状况的演化与变迁。因此, 植被覆盖变化研究已成为揭示干旱区自然环境变化及其规 律的重要手段。本文针对干旱区黑河下游这一特殊地域及其植被生态系统存在的问题, 综述了植 被覆盖变化及与其密切相关的地下水、土壤水盐平衡、全球气候变化和人类活动等因素的关系, 目的是全面分析与植被覆盖变化相关的各因素, 为分析植被覆盖变化机理及进一步研究黑河下 游生态环境演变服务。最后总结了目前黑河下游植被覆盖变化研究中存在的问题, 并提出了相应 的解决策略, 为区域植被覆盖变化研究提供了参考依据。  相似文献   

17.
梭磨河流域气候波动和土地覆被变化对径流影响的模拟研究   总被引:16,自引:4,他引:12  
陈军锋  张明 《地理研究》2003,22(1):73-78
利用一个集总式水文模型(CHARM),模拟了不同的气候与土地覆被条件下长江上游梭磨河流域的水量平衡,定量区分气候波动和土地覆被变化对水文影响的“贡献率”。模型模拟的初步结果表明,从20世纪60年代到80年代,径流深增加了45.7mm,其中,由气候波动所引起的年平均径流深的增加占63.9%,由土地覆被变化所引起的径流深的增加占20.8%,其他条件的变化所引起的径流深的增加占15.3%。  相似文献   

18.
There are over 500 species of arthropods recorded from Svalbard. These animals overwinter either within the soil or on the ground surface, and have to tolerate an environment where the ground is frozen for over 9 months each year. Three cold-tolerance strategies have been described from Svalbard invertebrates: freeze avoidance, freeze tolerance and desiccation. Once in a cold-tolerant state the animals can be extremely cold tolerant in terms of both minimum exposure temperature and period of exposure. How the overwintering capabilities of these animals will be affected by climate changes during the next 100 years, as predicted by climate models, is not yet known. Four principle factors with an impact on overwintering of the terrestrial arthropod fauna are outlined here: (1) warmer winter temperatures, with an increased frequency of extreme events such as freeze–thaw cycles and surface icing; (2) changes in snow fall and snow lie; (3) pollutant load; and (4) dispersal of invertebrates to Svalbard. Finally, areas where further research is required are highlighted: including the development of controlled multi-season field experiments; effect of freeze–thaw cycles; changes in thickness and distribution of snow lie, with the subsequent effects on duration of the summer period; chill susceptibility of soil arthropods; assessing potential colonizing species and the likelihood of these species becoming established; assessing the effect of gene flow from surrounding populations; interactions between pollution and cold tolerance; anoxia stress; and the genetics of cold tolerance.  相似文献   

19.
植被作为干旱区敏感的环境要素, 能直观反映自然环境状况, 任何植被覆盖变化都可揭 示区域环境状况的演化与变迁。因此, 植被覆盖变化研究已成为揭示干旱区自然环境变化及其规 律的重要手段。本文针对干旱区黑河下游这一特殊地域及其植被生态系统存在的问题, 综述了植 被覆盖变化及与其密切相关的地下水、土壤水盐平衡、全球气候变化和人类活动等因素的关系, 目的是全面分析与植被覆盖变化相关的各因素, 为分析植被覆盖变化机理及进一步研究黑河下 游生态环境演变服务。最后总结了目前黑河下游植被覆盖变化研究中存在的问题, 并提出了相应 的解决策略, 为区域植被覆盖变化研究提供了参考依据。  相似文献   

20.
Lithologic and geochemical data of a core from the Hwajinpo Lagoon, located on the eastern coast of Korea, provided the evolutionary history of the lagoon related to Holocene sea-level changes of the East Sea (Sea of Japan). Grain size analysis, water content analysis, and soft X-ray analysis of core samples were used to reconstruct sedimentary environments, as were total organic carbon, C/N, S and C/S chemical records. Assemblages of mollusc and diatom remains also provided paleoenvironmental information. The reconstruction of paleoenvironments from these multi-proxy data allows the establishment of an evolutionary model of the Hwajinpo Lagoon. The environmental changes of the Hwajinpo Lagoon can be divided into seven different depositional facies: (l) Exposed basement rock; (2) Estuarine; (3) Stagnant brackish lagoon (isolated); (4) Oxic condition lagoon (organic activity); (5) Fresh water lake; (6) Oxic brackish lagoon (recent condition); (7) Prograding river delta. These environmental changes can be related to sea-level change during the Holocene. The trends of sea-level change in the Hwajinpo Lagoon from this study can be compared to those of the Japanese coastal areas located on the other side of the East Sea such as Lakes Shinji and Nakaumi.  相似文献   

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