期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
河流碳通量与陆地侵蚀研究 被引量:44
1
作者 高全洲 沈承德 《地球科学进展》 CAS CSCD 1998年第4期369-375,共7页
河流碳通量系陆地侵蚀产物,它构成全球碳循环的一个重要环节。河流碳通量在数量上远小于全球碳循环的其他环节,但由于与陆地生态系统联系密切,故对它的研究尤为重要。全球每年河流碳通量约为1GtC(109t碳),其中约60%为... 河流碳通量系陆地侵蚀产物,它构成全球碳循环的一个重要环节。河流碳通量在数量上远小于全球碳循环的其他环节,但由于与陆地生态系统联系密切,故对它的研究尤为重要。全球每年河流碳通量约为1GtC(109t碳),其中约60%为无机碳、40%为有机碳。溶解态有机碳和颗粒状有机碳主要来源于土壤侵蚀,另有一部分有机碳来源于河湖中的浮游植物;溶解态无机碳主要源于大气中CO2和碳酸盐;颗粒无机碳主要指未溶解的碳酸盐。亚洲季风区河流对全球河流碳通量具有较大贡献,而对其研究程度较低。河流碳通量研究既可为流域治理提供基础资料,也是进一步了解人为CO2“未知汇”的途径之一。 展开更多
关键词 河流 碳通量 陆地侵蚀 温室效应 二氧化碳
下载PDF
河流碳输移与陆地侵蚀-沉积过程关系的研究进展 被引量:11
2
作者 姚冠荣 高全洲 《水科学进展》 EI CAS CSCD 北大核心 2007年第1期133-139,共7页
河流碳输移与陆地侵蚀-沉积过程紧密相关。首先就机械和化学风化两种不同的陆地侵蚀机制在提供河流碳源方面所发挥的不同作用作了详细论述,并比较了季风流域和非季风流域间河流碳输移在通量及性质上的差异。之后对陆地碳沉积机制进行了... 河流碳输移与陆地侵蚀-沉积过程紧密相关。首先就机械和化学风化两种不同的陆地侵蚀机制在提供河流碳源方面所发挥的不同作用作了详细论述,并比较了季风流域和非季风流域间河流碳输移在通量及性质上的差异。之后对陆地碳沉积机制进行了归纳,指出了包括大坝截留,河漫滩、河口-近岸带沉积及陆地碳沉降等几种可能的陆源碳踪迹。陆地环境的截留效应相对于侵蚀尚不太清楚,今后应加强对陆地碳沉积的研究,进一步明确各种碳沉积的作用机制及其对全球陆地碳汇的贡献量。此外,人类活动对陆地侵蚀-沉积过程及河流碳循环所产生的直接或间接的影响也有待于今后继续深入探索。 展开更多
关键词 河流碳输移 陆地侵蚀-沉积 通量 陆源 人类活动
下载PDF
雷州半岛第四纪台地区的崩岗侵蚀地貌──一种后果严重的水土流失现象 被引量:7
3
作者 匡耀求 孙大中 《热带地理》 北大核心 1998年第1期42-49,共8页
雷州半岛中段酉部的第四纪台地区,水土流失十分严重,崩岗地貌在水土流失面积中所占的比例已接近20%,对区域生态环境造成了严重的破坏,若任其发展下去,数百年后可能将侵蚀区蚀切到海平面以下,形成一条横切雷州半岛的海峡,严重威... 雷州半岛中段酉部的第四纪台地区,水土流失十分严重,崩岗地貌在水土流失面积中所占的比例已接近20%,对区域生态环境造成了严重的破坏,若任其发展下去,数百年后可能将侵蚀区蚀切到海平面以下,形成一条横切雷州半岛的海峡,严重威胁到区域的可持续发展。通过实地调查,分析了水土流失的发育背景,总结其发育特点,认为造成其水土流失不断加剧的原因主要是其特殊的地层结构和岩性特点以及不合理的土地利用方式。因此应高度重视沿海第四系出露区的陆地侵蚀与水土流失问题;这些地区的开发和建设必须建立在充分认识其地层岩性背景和侵蚀影响因素的基础上,必须加强对地质基础的研究工作。 展开更多
关键词 水土流失 陆地侵蚀 崩岗 雷州半岛 侵蚀地貌
下载PDF
Analysis of Social and Psychological Terrain of Bank Erosion Victims: A Study Along the Bhagirathi River, West Bengal, India
4
作者 Aznarul ISLAM Sanat Kumar GUCHHAIT 《Chinese Geographical Science》 SCIE CSCD 2018年第6期1009-1026,共18页
Social psychology of people affected by hazards is different from normal psychology. For example, severe bank erosion in the lower reach of the Bhagirathi River in West Bengal has resulted in significant land loss (-... Social psychology of people affected by hazards is different from normal psychology. For example, severe bank erosion in the lower reach of the Bhagirathi River in West Bengal has resulted in significant land loss (-60% of all households lost land over last 20 years) and affected the livelihoods of the people in the study villages along the river. Per capita income has almost halved from 1970-2012 due to land loss. This stark nature of land erosion and vulnerability of livelihood has had far-reaching repercussions on the fabric of society and the psychology of the people in this region. Results showed that erosion-affected villages have registered compara- tively larger average family sizes (-4.1 as compared to -3.9 in non-affected villages), lower literacy levels (〈 50% compared to 〉 65% for the non-affected villages), and poor health. Reports of poor health as a result of land erosion include -60% of the respondents having reported physical ailments such as headache and abdominal discomfort, as well as 3%-5% reporting loss of emotional and psychological balance. Villages suffering from erosion showed higher positive loadings in average-coefficient of variation (CV) differential (25%-40%) depicting objectivity in their opinions for select variables of social processes. Principal component analysis (PCA) por- trayed maximum eigenvalues in the first principal component for interpersonal processes (-98%) and a minimum for intergroup proc- esses (-80%). Categorical principal component analysis (CATPCA) depicted a cluster between interpersonal and intergroup processes and another between intra-individual and group categories. The positive loadings in female-male differences in CV of perceptions portrayed relative consistency of males over the females concerning fear/phobia and physical stress while negative loadings exhibited higher consistency for females regarding psychological stress and shock. Lastly, the Taj fel matrix portrayed a distinction between hazard psychology characterized by maximum joint profit as found in Rukunpur, and normal psychology characterized by in-group favoritism as found in Matiari. 展开更多
关键词 social terrain psychological terrain riverbank erosion principal component analysis Tajfel matrix Bhagirathi River
下载PDF
Causes of Land Loss in Tuvalu,a Small Island Nation in the Pacific
5
作者 XUEChunting 《Journal of Ocean University of China》 SCIE CAS 2005年第2期115-123,共9页
Studies on land loss in Tuvalu reveal the following findings. Although both sea level rise and coastal erosion can cause land loss in the tropic Pacific oceanic islands, their mechanisms are different. When sea level ... Studies on land loss in Tuvalu reveal the following findings. Although both sea level rise and coastal erosion can cause land loss in the tropic Pacific oceanic islands, their mechanisms are different. When sea level rises, the low elevation coastal zone submerges and the erosion datum plane rises, the beach process progresses normally as always, resulting in no beach sediment coarsening. When the sea level is stable, coastal erosion removes finer sediment from reef flat, beach and land, resulting in beach sediment coarsening. The human-induced coastal erosion in the tropic Pacific oceanic islands has the following features. 1) Erosion occurs or intensifies immediately after inappropriate human activities. 2) It occurs near the places having human activities and places related to the above places in sediment supply. 3) It often occurs on original prograding or stable coasts (on lagoon coasts for atolls) because there are more coastal engineering projects and other human activities on such coasts. 4) It is chronic, covering a long period of time. The coastal geological events in Tuvalu islands do not accord with the features resulted from sea level rise but do accord with the features resulted from coastal erosion, particularly from human-induced erosion. The land loss in Tuvalu is mainly caused by inappropriate human activities including coastal engineering and aggregate mining, and partly caused by cyclones. Moreover, all recent measurements (satellite altimetry,thermosteric sea level data and tide observations) so far have not been able to verify any sea level rise around Tuvalu islands. 展开更多
关键词 sea level rise land loss coastal erosion artificial channel aggregatemining
下载PDF
Land Degradation Evaluation in North Hebei Province Based on Remote Sensing and GIS
6
作者 Yuan Jinguo Liu Jinsong +1 位作者 Wang Wei Niu Zheng 《Chinese Journal of Population,Resources and Environment》 北大核心 2006年第3期28-36,共9页
Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North He... Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960′s to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent. 展开更多
关键词 land degradation North Hebei Province soil erosion intensity arable land suitability evaluation
下载PDF
Spatial analysis of the impact of land-use on surface runoff and soil erosion—a case study of western Jilin
7
作者 Juana P Moiwo 《Global Geology》 2006年第1期80-93,共14页
The impact of land-use on surface runoff and soil erosion is still poorly understood at basin scale. Thus in the Western Jilin Ecosystem (WJE), surface runoff and soil erosion were measured against identified land-use... The impact of land-use on surface runoff and soil erosion is still poorly understood at basin scale. Thus in the Western Jilin Ecosystem (WJE), surface runoff and soil erosion were measured against identified land-use types in the basin. Due to the spatial nature of the analysis, GIS ArcMap version 9.1 and the WetSpass model were used in the simulation process. In the study, the WetSpass model was extended with the Dynamic Sediment Balance Equation (Ziegler et al., 1997), to simulate and quantify soil erosion. A hypothetical natural grassland scenario was developed for the study area and compared with the present land-use management conditions. The results indicate significant differences in runoff and soil erosion across the different land-use types both within and between the two scenarios. Calculated averages of surface runoff and soil erosion for the present land-use management were 48.03 mm/a and 83.43 kg/(m 2·a) respectively. Those for the hypothetical natural grassland scenario were 24.70 mm/a and 78.36 kg/(m 2·a) . Thus an overall decrease in runoff and soil erosion was observed as the conditions changed from the present land-use management to the hypothetical natural grassland state. Under the present land-use management, urban settlements exhibited the highest surface runoff but one of the least soil erosions, while bare-lands showed the highest soil erosion. It was more generally observed that runoff and erosion varies with vegetation type/density. It was concluded based on the research findings that the present land-use management might not be the best scenario for the ecosystem as it showed increased basin runoff and soil erosion in comparison with the natural grassland vegetation. Since no best scenario was simulated for or advanced in the study, further research to develop a more balanced land management system is thus required. The findings of the study can assist in the identification of vulnerable/fragile ecosystems in the basin and to guide sustainable future planning and development of the basin. 展开更多
关键词 wetspass land-use surface runoff soil erosion western Jilin ecosystem
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部