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广东沿海赤潮发生与城市发展的关系 总被引：2，自引：0，他引：2
Red tides are one of the main coastal catastrophic events in Guangdong Province of southern China. The comparison between the number of red tide events and the development indexes of cities along the coasts of the province shows that the regional differences in red tide outbreaks has close relations with the coastal urban developments. The cause for an initiation of red tide blooms may be natural factors, while wastewater caused by the fast development of population, industry and aquiculture of the coastal cities enhanced the blooms. It may explain why the two periods of frequent outbreaks of the red tides over the last two decades matched the urban developments in the coastal areas of Guangdong not only spatially but also temporally. The red tides in the first period were restricted only to the coasts of middle Guangdong, where urbanization process was at a higher speed than the other coastal areas of the province. In the second period, fast development of the coastal cities in eastern Guangdong led to an increase in the occurrence of red tides in local sea areas of the same coasts. 相似文献
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Leaf area is an important parameter for modeling plant growth and physiological processes.It is very expensive and difficult for measuring leaf area by means of Leaf Area Meter,therefore,it’s quite necessary to obtain one simple model for estimation of leaf area of mangrove tree.The models for estimation of leaf area of 3 species of mangrove trees were developed based on leaf length and width.Totally,leaf area(LA),leaf length(L)and width(W)were measured from 450 fresh leaves of major three species of mangrove trees in Zhangjiang Estuary Mangrove National Natural Reserve,Fujian province.The actual leaf area of the plant was measured with the help of ArcGIS software and regression model was fitted.The majority of the data(80%)were used for model calibration,and the remaining data(20%)were used for model validation.All the leaf areas of 3 species of mangrove trees had been significant correlation between L,W,L·W,L2,W2and(L+W)2,so the factors could be constructed into a regression model with leaf area.Six models for estimation of leaf area selected were significantly(p0.001)regressed with L,W and the functions of these dimensions.All models were linear relationships.Based on goodness of fit,prediction ability and residual performance,it was found that model 3 could best describe the relationship between leaf area and leaf length and width.By means of regression analysis,the following models were developed:LA=0.28+0.66L·W(R2=0.980)for Kandelia candel,LA=0.09+0.73L·W(R2=0.983)for Avicennia marina,LA=0.52+0.72L·W(R2=0.990)for Aegiceras corniculatum,respectively.The study provided a simple,reliable and non-destructive method for estimating single leaf area.It had a good potential in the functional structural model of mangrove tree. 相似文献
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IntroductionAlmost all the provinces and autonomous regions in China have experienced decrease of arable land in the processes of economic development, population growth and urbanization. The situation is more serious in Shandong Province because of the big population and being an agricultural province. From 1949 to 1999, the arable land was decreased by more than 2 million ha in this province accompanied by rapid population growth. The total population in the province in 1999 was twice of t… 相似文献
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Wu Li Sun Xiaoling Sun Wei Zhu Cheng Zhu Tongxin Lu Shuguang Zhou Hui Guo Qingchun Guan Houchun Xie Wei Ke Rui Lin Guiping 《地理学报(英文版)》2020,30(9):1451-1466
Based on archaeological surveys of Neolithic cultural development and GIS spatial analysis,this study reproduced the main characteristics of temporal distribution and settlement selection of the sites from the Neolithic Age in Anhui and identified a relationship between environmental evolution and human activity.The results show that altitude,slope direction,and slope gradient were consistent among the settlements at different stages of the Neolithic Age in Anhui,and the sites were mostly distributed in hilly and plain areas on southeast-or south-facing slopes of low gradients close to rivers.We determined that early Neolithic Age(9.0–7.0 ka BP) sites were scattered in small numbers and likely had little cultural exchange with communities of other provinces.The environmental characteristics of various regions in Anhui indicated that the climate was warm and humid with extensive water distribution.The sites of the mid Neolithic Age(7.0–5.0 ka BP) increased rapidly with wide distribution.They were mainly distributed in the plain area north of the Huaihe River and the southwestern areas of Anhui.In the mid Neolithic Age,the warm and humid climate gradually dried,and our ancestors slowly developed cultural exchanges.The largest number of sites existed during the late Neolithic Age(5.0–4.0 ka BP),and were distributed throughout the province.During this period,the overall climate was relatively dry,but humans could still obtain water and other resources through migration.The relatively benign climate facilitated cultural interaction and exchange,which increased during this time,and the Wanjiang culture matured.We also determined that as early civilization evolved,cultures in different regions responded differently to environmental changes.In humid subtropical regions,especially in low-lying plains and areas beside lakes,rivers,and coastal areas,the relatively dry climate in the late period of the middle Holocene,prefaced by a period of high humidity,was conducive to the development of human culture.The evidence from the Neolithic settlements in Anhui therefore reflects this subtropical man-land relationship between cultural development and environmental conditions. 相似文献
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《地理学报(英文版)》2019,(10)
The cultivation of mountainous land results in water loss and soil erosion. With rapid urbanization and industrialization in China, labor emigration relieves the cultivation of mountainous areas in regions with high poverty and leads to a significant land use transition. This research built an analysis framework for "land use transition – driving mechanism – effects –responses" for mountainous areas of China undergoing land use transition and then proposed the direction of mountainous land consolidation. The results showed that the turning point of land use morphology was the core of rural land use transition in mountainous areas. The expansion of cropland and the contraction of forestland have transitioned to the abandonment of cropland and the expansion of forestland; this transition was the main characteristic of the dominant land use change. Land marginalization and land ecological functional recovery were the main characteristics of the recessive land use transition in mountainous areas. Socioeconomic factors were the primary driving forces during land use transition in mountainous areas, with labor emigration being the most direct force. The rising costs of farming and the challenging living conditions causing labor emigration were fundamental driving forces. Rural land use transition in mountainous areas reduced the vulnerability of the ecological function of land ecosystems. The advantages and disadvantages of the socioeconomic effects should focus on rural development of mountainous areas as well as the livelihood of farmers; this should be further supported by empirical and quantitative research. Rural land use transition of mountainous areas improves natural restoration and is related to socioeconomic development. Rural land consolidation of mountainous areas should conform to land use transition,with the goal of shifting from the increase of cultivated land to the synergies of ecological and environmental protection. 相似文献
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湖北旧石器至战国时期(1.15MaBP-278BC)古文化遗址分布与环境演变(英文) 总被引：1，自引：1，他引：0
A total of 1362 archaeological sites from the Paleolithic Age to the Warring States time in Hubei Province increase gradually from west to east and from high land to low land.The number of Paleolithic sites with altitude of 50-500 m account for 78% of the whole,while 71%-95% of sites from the Neolithic Age to the Warring States time mainly distribute at the areas of 0-200 m.The temporal-spatial distribution of archeological sites in this area is affected by two factors.For one thing,the human beings of every period need to choose the first or the second terrace as living sites which are near water source and are easy to withstand flood.Additionally,affecting by the regional tectonic uplift since the Holocene,down cutting of rivers can form new river valley,and lateral erosion and accumulation of river in stable time of tectonic movement can result in increasing of many new terraces.So,the human beings migrated to adapt to the change of terrace location,leading to the sites increase gradually in the lower areas of the central and eastern parts of this province.For other things,the temporal-spatial distribution of archeological sites in this area is affected by the climate condition.The Paleolithic sites mostly distribute in the Hanshui River Valley in northeastern Shiyan,southeast of Jinzhou and east of Jinmen,which is because rivers distributed in higher areas in this period.During the Chengbeixi Culture period,the sites are rare in the quondam Paleolithic sites distribution area,but increase obviously along the Yangtze River near the southwest Yichang.The spore-pollen record of Dajiuhu Basin indicates that only 23 Chengbeixi cultural sites may be related to more precipitation and flood during the Holocene wet and hot period.The Daxi Culture,Qujialing Culture and Shijiahe Culture are corresponding to middle and top of the Dajiuhu spore-pollen Zone Ⅳ,during which the climate is in order as a whole and is propitious to agricultural development.In the Qujialing Culture period,32 of original 34 Daxi cultural sites disappeared,while 90 sites increase abruptly in the higher highlands in the north of Xiangfan-Jinmen-Xiaogan,which may respect with enlarging of water areas.The Chu Culture period is corresponding to Dajiuhu spore-pollen Zone V,which is in warm and dry Holocene phase,but it seems that the climate condition is still propitious to agricultural cultivation and the number of archeological sites increase heavily to 593.In addition,there are the least archaeological sites in the lake areas of southeast Hubei Province because of low-lying topography with altitude of 0-50 m and the severest flood. 相似文献
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新疆克拉玛依市生态敏感性研究(英文) 总被引：2，自引：1，他引：1
Karamay City is a typical mining city, relying on oilfield exploration and development. After 60 years of construction and development, Karamay has become the first large oilfield and an important base of the national petroleum and petrochemical industry in China. Based on spatial analysis, and Geographic Information Systems (GIS) grid computing and overlay techniques, whilst considering the effect of oilfield development and aimed at the ecological problems of Karamay City in the Xinjiang Uygur Autonomous Region of China, we conducted research on the spatial characteristics of the comprehensive ecological sensitivity of Karamay. The ecological problems of natural environment evolution include soil erosion, land deserti-fication, soil salinization, and biodiversity reduction. The most significant disturbance factor from the activities of humans in this area is oilfield exploitation. This study carries out an analysis of single factor ecological problem sensitivity and integrated ecological sensitivity. The results of the research are as follows: (1) Soil erosion is relatively sensitive, especially in Karamay district, Dushanzi district, north of Urho district and west of Baijiantan district, which is mainly a result of the vertical dropping slopes, serious rainfall erosion and the distribution of scattered woodland. (2) The main types of land desertification are represented by high and moderate grade sensitivities, and high and extremely high sensitive areas are distributed in the intersection of Karamay and Baijiantan districts. This is due to evaporation exceeding rainfall in these areas, and the soil mainly consists of sand and is seldom covered by vegetation. (3) The soil salinizatiion sensitivity grades are mainly moderate, high and extremely high. The highly sensitive areas are mainly distributed in southeast of Baijiantan district, north and east of Karamay district and east of Urho district. The primary causes are evaporation exceeding rainfall and extreme human activities. (4) The main types of biodiversity sensitivity are light and moderate grade. Highly sensitive areas are located in the east and south of Karamay district, north of the Baiyang River basin and parts of the wetland areas. (5) Oil fields development areas are highly ecologically sensitive, which are located in the northern oilfields of Urho district, western oilfields of Baijiantan district, northwestern oilfields of Karamay district and central oilfields of Dushanzi district. (6) The main types of integrated ecological sen-sitivity are high and moderate. The high and extremely highly sensitive areas are located in the central and northern parts of Karamay district, and southwest of Baijiantan district. The evaluation results will provide guidance for the future planning and development, the protection of the ecological environment and the realization of harmonious social, economic, and ecological development in Karamay City. 相似文献
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《地理学报(英文版)》2017,(7)
Geographically explicit historical land use and land cover datasets are increasingly required in studies of climatic and ecological effects of human activities. In this study, using historical population data as a proxy, the provincial cropland areas of Qinghai province and the Tibet Autonomous Region(TAR) for 1900, 1930, and 1950 were estimated. The cropland areas of Qinghai and the TAR for 1980 and 2000 were obtained from published statistical data with revisions. Using a land suitability for cultivation model, the provincial cropland areas for the 20 th century were converted into crop cover datasets with a resolution of 1 × 1 km. Finally, changes of sediment retention due to crop cover change were assessed using the sediment delivery ratio module of the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) model(version 3.3.1). There were two main results.(1) For 1950–1980 the fractional cropland area increased from 0.32% to 0.48% and land use clearly intensified in the Tibetan Plateau(TP), especially in the Yellow River–Huangshui River Valley(YHRV) and the midstream of the Yarlung Zangbo River and its two tributaries valley(YRTT). For other periods of the 20 th century, stability was the main trend.(2) For 1950–1980, sediment export increased rapidly in the Minhe autonomous county of the YHRV, and in the Nianchu River and Lhasa River basins of the YRTT, which means that sediment retention clearly decreased in these regions over this period. The results of this assessment provide scientific support for conservation planning, development planning, or restoration activities. 相似文献
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《地理学报(英文版)》2019,(5)
Land use in the northeast region of Thailand has changed dramatically in the past two decades. These changes are mainly due to the government policies, which launched a scheme to promote rubber plantation during 2003–2013 targeting to solve the problem of poverty in the region. At least 50,000 ha of paddy fields were found to be converted to other land use types between 2002 and 2012. This study was conducted in Nong Khai and Bueng Kan province of northeast Thailand, where massive rubber plantation is going on prompting significant amount of land-use change, with the objective of investigating how land-use changes will affect on food availability in future. We analyzed land-use changes of the past and simulated future land uses using GIS and Landsat Thematic Mapper Data. The most obvious change was the decrease in paddy field and an increase in rubber plantation. This eventually leads to decreased paddy production affecting food supply of farm households. The land use projections for 2032 were done for three scenarios using Dyna-CLUE model. Unlike business as usual scenario, which will further decrease the paddy area, other scenarios with different land use policies if implemented will help protect paddy areas and thus achieving higher food production locally. The lack of implementation of proper spatial policies will lead to a further loss of paddy areas at macro level.The smallholder farmers may be highly vulnerable to land use-change and experience significant food crop losses, food insecurity and income loss when they change the land to rubber and there is market failure. 相似文献
10.
海河流域及周边地区太阳辐射变化成因 总被引：1，自引：1，他引：0
Solar radiation is an important driving force for the formation and evolution of climate system. Analysis of change in solar radiation is helpful in understanding mechanism of climate change. In this study, the temporal and spatial variations of solar radiation and the cause of the change in solar radiation have been analyzed based on meteorological data from 46 national meteorological stations and aerosol index data from TOMS over the Haihe River Basin and surrounding areas. The results have shown that solar radiation and direct radiation significantly decreased, while scattered radiation increased during the period 1957–2008. Spatially, the decreasing trend of solar radiation was more and more significant from low population density areas to high population density areas. The spatial distribution of increase in aerosol index is consistent with that of decrease in solar radiation. The increase in aerosols resulting from human activities was an important reason for the decrease in solar radiation. 相似文献
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Mangrove forests have important ecological functions in protecting the environment. However, the mangrove wetlands have been largely lost because of intensified human activities in the study area. Remote sensing can be conveniently used for the inventory of mangrove forests because field investigation is very difficult. In this study, a knowledge-based system is developed to retrieve spatio-temporal dynamics of mangrove wetlands using multi-temporal remote sensing data. Radar remote sensing data are also used to provide complementary information for the quantitative analysis of mangrove wetlands. Radar remote sensing is able to penetrate mangrove forests and obtain the trunk information about mangrove structures. The integration of radar remote sensing with optical remote sensing can significantly improve the accuracies of classifying mangrove wetland types and estimating wetland biomass. 相似文献
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无人机遥感在红树林资源调查中的应用 总被引：6，自引：0，他引：6
低空无人机（UAV,Unmanned Aerial Vehicles）遥感系统具有数据采集灵活、低成本且可快速获取超高分辨率影像的特色,是传统航空遥感和卫星遥感的重要补充。以广东省和广西壮族自治区交界处的英罗港港湾两侧为研究区域,将无人机遥感系统用于红树林资源的遥感调查,通过无人机航拍获取高分辨率影像,并且使用拼接的影像和目视解译方法提取红树林空间分布信息,进一步选择典型研究样地,采用面向对象的最近邻分类方法对红树林树种类型进行分类研究,并对比综述了无人机遥感和常规航空航天遥感技术对红树林资源调查监测的优缺点,无人机遥感系统非常适用于红树林资源调查。通过2 h 30 min的3架次无人机航飞工作,获取了研究区域25.29 km2的无人机影像,基于无人机影像和面向对象遥感分类方法提取的红树林空间分布信息精度超过了90%。未来无人机遥感系统将可成为调查和监测红树林资源的重要技术手段,可为相关管理部门对红树林资源的保护、管理、开发等方面的工作提供基础信息和技术支持。 相似文献
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我国红树林湿地研究进展 总被引：15，自引：3，他引：15
红树林湿地是分布于亚热带、热带滨海地区的典型湿地，具有其它湿地类型所不具备的特殊的演化过程，形成独特的水文、土壤和植被特征。由于人类活动的影响，近年来，我国红树林湿地出现了面积锐减、生态系统结构简化、生物多样性降低、生态功能退化等严重问题，使红树林湿地的可持续利用面临严重挑战。从湿地生态、湿地功能及湿地开发利用、保护与管理等方面评述我国红树林湿地生态系统的研究现状，探讨我国红树林湿地未来研究的主要科学问题，进而明确红树林湿地可持续利用研究的方向和途径。 相似文献
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在遥感和地理信息系统技术支持下,利用湿地调查资料、地图和遥感影像数据,获得1956~2016年期间9个时期湖南省的湿地数据;采用景观分析方法,系统地分析了9个时期湖南省的湿地分布及其变化特征和湿地景观格局变化及其影响因素。研究结果表明,与1956年相比,2016年湖南省的湿地面积减少了955.4 km^2,其中,永久性淡水湖泊和河流面积明显减少,水产养殖场面积明显增加;湿地的景观结构也相应地发生了改变,1986年湖南省的湿地的破碎化程度最严重;1956~2016年期间,湿地景观类型分布不均衡程度在不断加剧;永久性河流和永久性淡水湖泊是湖南省的优势湿地景观类型,且永久性淡水湖泊的最大斑块指数都远大于其它类型湿地;围垦和退耕还湿活动是影响湿地变化的主要因素。 相似文献
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黄河三角洲刁口河流路湿地恢复遥感监测与评价 总被引：1，自引：0，他引：1
利用卫星遥感技术对生态调水及湿地恢复进行实时动态监测, 不仅可以及时掌握宏观地表的快速变化, 还可以为长期的区域生态效应评价提供支持。基于国产自主环境一号小卫星遥感数据, 对2010 年黄河三角洲生态调水暨刁口河流路恢复过水试验进行动态监测和初步评价。研究表明, 刁口河流路恢复过水后, 原废弃河道过流条件得到提高, 部分被开发利用的河滩地得到恢复, 水文条件好转, 河流水面面积总体上增加了526 hm2, 有利于河道生态条件的改善。通过对湿地引水修复, 自然保护区试验区块共有437 hm2的退化湿地得到了较大程度的改善。同时, 湿地景观多样性提高, 对维持区域景观多样性、改善鸟类栖息地质量具有重要意义。研究结果表明, 国产环境一号卫星遥感数据能提供丰富的地面信息, 其数据具有较高的时间分辨率, 可以作为中国湿地调查和监测的重要数据源。考虑到大尺度调水和湿地恢复对区域生态环境的影响是一个长期的过程, 今后应进一步挖掘环境一号卫星现有波段的光谱信息, 对湿地恢复进行长期跟踪监测, 为湿地恢复生态效应综合评估提供技术支撑。 相似文献