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101.
1982~1999年中国地区叶面积指数变化及其与气候变化的关系   总被引:1,自引:0,他引:1  
利用1982~1999年AVHRR Pathfinder卫星遥感观测的植被叶面积指数(leaf area index,LAI)资料和中国730个气象台站的温度、降水观测资料,研究了中国不同地区(东北地区、华北地区、长江流域、华南地区和西南地区)LAI的季节、生长季和年变化,及其与气候变化(温度、降水)的关系。结果表明,在中国大部分地区,年平均LAI和生长季平均LAI均是增加的。由于区域和季节气候的差异,LAI变化趋势具有明显的空间和季节非均一性。从区域平均的角度来看,不同地区年和生长季平均LAI都有增加趋势,并且在华南地区增加最快。因而,在全球变化背景下,华南地区可能是潜在的碳汇。在季节尺度上,各地区区域平均LAI基本上都是增加的,并且都在春季增加最快。温度变化是LAI变化的主要原因。但是人类活动如农业活动、城市化等对华北平原、长江三角洲和珠江三角洲等地区LAI变化的作用不容忽视。  相似文献   
102.
城市边缘区景观变化与人为影响的空间分异研究   总被引:38,自引:5,他引:38  
陈浮  葛小平  陈刚  彭补拙 《地理科学》2001,21(3):210-216
利用1988、1993、1998年的遥感影像,应用最大似然法和概率松弛法对马山景观组分进行了测量,在此基础上,对分类结果进行比较求得研究区景观变化的转移短也阵,分析了人为改造活动与景观组分之间的对应关系和空间变化过程,马山区已经从1988年的传统农业景观转化为1998年的城郊混合景观,人口、经济、产业结构均发生了巨大变化,借助人为影响指数,利用网格采样和地统计学分析,研究了马山1988-1998年间景观的人为开发利用活动,揭示人为活动的空间变异强度分布及景观转变过程的社会驱动力。  相似文献   
103.
Runoff reduction due to environmental changes in the Sanchuanhe river basin   总被引:10,自引:1,他引:9  
Recently, runoff in many river basins in China has been decreasing. Therefore, the role that climate change and human activities are playing in this decrease is currently of interest. In this study, we evaluated an assessment method that was designed to quantitatively separate the effects of climate change and human activities on runoff in river basins. Specifically, we calibrated the SIMHYD rainfall runoff model using naturally recorded hydro-meteorologic data pertaining to the Sanchuanhe River basin and then determined the effects of climate change and human activities on runoff by comparing the estimated natural runoff that occurred during the period in which humans disturbed the basin to the runoff that occurred during the period prior to disturbance by humans. The results of this study revealed that the S1MHYD rainfall runoff model performs well for estimating monthly discharge. In addition, we found that absolute runoff reductions have increased in response to human activities and climate change, with average reductions of 70.1% and 29.9% in total runoff being caused by human activities and climate change, respectively. Taken together, the results of this study indicate that human activities are the primary cause of runoff reduction in the Sanchuanhe River basin.  相似文献   
104.
The eco-environmental susceptibility is to demonstrate the reaction of a ecosystem under the same influences of the human activity. It comprise many influencing factors which have a complicated relation to the eco-environmental susceptibility. In this paper, the Analysis of Hierarchy Process (AHP) is used to determine the weight of each factor to the eco-environmental susceptibility through analyzing the relationship between human activity and environmental deterioration. And the weighted summation method is used to calculate the eco-environmental susceptibility of different divisions in Yulin region. The result shows that the loess hilly and gully area is more subjective to deteriorating eco-environment than the desert area because of the strong human activity and severe soil erosion. The project is supported by the National Natural Science Foundation of China  相似文献   
105.
Analyzing the spatial and temporal properties of information flow with a multi-century perspective could illuminate the sustainability of human resource-use strategies. This paper uses historical and archaeological datasets to assess how spatial, temporal, cognitive, and cultural limitations impact the generation and flow of information about ecosystems within past societies, and thus lead to tradeoffs in sustainable practices. While it is well understood that conflicting priorities can inhibit successful outcomes, case studies from Eastern Polynesia, the North Atlantic, and the American Southwest suggest that imperfect information can also be a major impediment to sustainability. We formally develop a conceptual model of Environmental Information Flow and Perception (EnIFPe) to examine the scale of information flow to a society and the quality of the information needed to promote sustainable coupled natural-human systems. In our case studies, we assess key aspects of information flow by focusing on food web relationships and nutrient flows in socio-ecological systems, as well as the life cycles, population dynamics, and seasonal rhythms of organisms, the patterns and timing of species’ migration, and the trajectories of human-induced environmental change. We argue that the spatial and temporal dimensions of human environments shape society’s ability to wield information, while acknowledging that varied cultural factors also focus a society’s ability to act on such information. Our analyses demonstrate the analytical importance of completed experiments from the past, and their utility for contemporary debates concerning managing imperfect information and addressing conflicting priorities in modern environmental management and resource use.  相似文献   
106.
由于OLS传感器航行过程中增益记录和交叉定标的缺失,使得DMSP夜光影像在城市中心出现过度饱和等问题,因此探讨灯光数据去饱和方法在人类活动强度评估和城市时空演化分析等方面具有重要意义。为了解决这一难题,有学者提出使用NDVI修正饱和灯光数据的VANUI指数,为研究灯光数据去饱和提供了简单便捷的思路,然而该指数在部分城市中较难有明显的校正效果。本文在VANUI指数思想的基础上,顾及到人口密度随着郊区到城市中心距离的增加呈现指数型增长,提出了基于复合指数模型校正夜间灯光指数CEANI,为人类活动强度评价等研究提供更准确的结果。研究表明:① 与VANUI相比,CEANI在刻画城市内部饱和区域特征时具有更好的细节,较好地凸显城市内部空间异质性;② 在25组随机样本的相关对比中,CEANI(R2mean=0.79)与辐射定标产品比VANUI(R2mean=0.68)具有更高的相关性;③ 三大城市群中CEANI与常住人口的R2分别为0.767、0.676和0.841,比VANUI(R2分别为0.640、0.553和0.775)分别提高了0.127、0.123、0.066,相较于VANUI,CEANI与常住人口具有更强的相关性,对于人口指标的估算能力更强。  相似文献   
107.
The Dmanisi site has yielded human remains and lithic industry associated with Late Pliocene-early Pleistocene fauna. The site is composed of volcanogenic sediments overlying basaltic lava flows. The lithostratigraphic sequence comprises two basic depositional units: Unit A, overlying the basalt flows, and Unit B on top. A paleomagnetic and rock-magnetic study has been carried out on 106 specimens from Units A and B and the uppermost basalt flow. The lava and Unit A provide normal polarities, while reversed polarities and anomalous directions are observed in Unit B, the latter probably due to overlapping of a secondary and a primary reversed polarity component. The lower part of the section shows a clear correlation with the Olduvai subchron, and the upper levels could be as young as 1.07 Ma. As human remains were found both in units with normal and reversed polarity, different non-contemporaneous human occupations might have been possible.  相似文献   
108.
Human mobility patterns have been widely investigated due to their application in a wide variety of fields, for example urban planning and epidemiology. Many studies have introduced spatial networks into human mobility analyses at the collective level. However, these studies merely analyzed spatial network structure, and the underlying collective mobility patterns were not further discussed. In this paper, we propose a collective mobility discovery method based on community differences (CMDCD). We constructed spatial networks where nodes represent geographical entities and edge weights denote collective mobility intensity between geographical entities. The differences between communities detected from the networks constructed in different periods were then identified. Since collective spatial movement has a large influence on network structure, we can discover groups with different mobility patterns based on community differences. By applying the method to data usage detail records collected from the cellular networks in a city of China, we analyzed different collective mobility patterns between the Spring Festival vacation and workdays. The experimental results show that our method can solve these two problems of identifying community differences and discovering users with different mobility patterns simultaneously. Moreover, the CMDCD method is an integrated approach to discover groups whose mobility patterns have changed in different periods at the large spatial scale and the small spatial scale. The discovered collective mobility patterns can be used to guide urban planning, traffic forecasting, urban resource allocation, providing new insights into human mobility patterns and spatial interaction analyses.  相似文献   
109.
自然的社会建构:西方人文地理学对自然的再认识   总被引:9,自引:4,他引:5  
朱竑  尹铎 《地理科学》2017,37(11):1609-1616
自然的社会建构作为西方人文地理学界对自然的再思考,渐成为理解自然与社会互动的重要理论框架,并逐步成为推动人地和谐、可持续发展研究的新范式。通过梳理自然的社会建构研究理论源起并对西方涉及自然的社会建构的研究文献进行全面梳理发现,自然的社会建构并非单纯指基于建构主义视角考察自然的知识生产或价值与意义,还应该关注自然被生产与形构的商品化过程。现有议题主要聚焦于政治与自然、商品化与自然、社会情感与自然以及日常生活与自然四大方面。在此基础上,进一步提出了国内未来研究需要关注的重要方向。  相似文献   
110.
目的 初步探讨P16INK4A联合HPV L1壳蛋白检测在宫颈鳞状上皮内病变诊断中的应用价值。方法 选择在温州市人民医院就诊患者,收集69例宫颈鳞状上皮内病变标本,行P16INK4A、HPV L1壳蛋白检测,分析P16INK4A、HPV L1壳蛋白及P16INK4A联合HPV L1壳蛋白在各级宫颈病变中的表达差异。结果 P16INK4A在LSIL组、HSIL组、SCC组中的阳性率分别为45.5%、85.2%、100.0%。同LSIL组比较,P16INK4A在HSIL组及SCC组阳性率明显升高(P<0.01)。HPV L1壳蛋白在LSIL组、HSIL组、SCC组中的阳性率分别为63.6%、18.5%、0%,HPV L1壳蛋白在LSIL组中阳性率明显低于HSIL组及SCC组(P<0.01)。随着宫颈病变加重,P16+/L1-阳性率有升高趋势(P<0.01),P16-/L1+阳性率有下降趋势(P<0.01)。LSIL组中P16+/L1-阳性率明显低于HSIL组和SCC组(P<0.01),SCC组P16+/L1-阳性率较HSIL组有明显提高(P<0.05)。LSIL组中P16-/L1+阳性率明显低于HSIL组和SCC组(P<0.01)。P16+/L1-较P16INK4、HPV L1壳蛋白单一检测筛查HSIL+特异性明显升高(P<0.01)。结论 P16INK4A联合HPV L1壳蛋白有望成为诊断宫颈鳞状上皮内病变的有效指标。  相似文献   
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