期刊文献+
共找到46篇文章
< 1 2 3 >
每页显示 20 50 100
Relationship Between Individuals’Epidemic Risk Perception Within Living Space and Subjective Well-Being:Empirical Evidence from China after the First Wave of COVID-19
1
作者 SONG Jiangyu ZHOU Suhong +1 位作者 KWAN Mei-Po ZHENG Zhong 《Chinese Geographical Science》 SCIE CSCD 2024年第2期369-382,共14页
It is common to observe the epidemic risk perception(ERP)and a decline in subjective well-being(SWB)in the context of public health events,such as Corona Virus Disease 2019(COVID-19).However,there have been few studie... It is common to observe the epidemic risk perception(ERP)and a decline in subjective well-being(SWB)in the context of public health events,such as Corona Virus Disease 2019(COVID-19).However,there have been few studies exploring the impact of individuals’ERP within living space on their SWB,especially from a geographical and daily activity perspective after the resumption of work and other activities following a wave of the pandemic.In this paper,we conducted a study with 789 participants in urban China,measuring their ERP within living space and examining its influence on their SWB using path analysis.The results indicated that individuals’ERP within their living space had a significant negative effect on their SWB.The density of certain types of facilities within their living space,such as bus stops,subway stations,restaurants,fast food shops,convenience shops,hospitals,and public toilets,had a significantly negative impact on their SWB,mediated by their ERP within living space.Additionally,participation in out-of-home work and other activities not only increased individuals’ERP within living space,but also strengthened its negative effect on their SWB. 展开更多
关键词 subjective well-being epidemic risk perception living space the density of facilities out-of-home activities
下载PDF
Economic significance and environmental impacts of the Song Dam Drinking Water Project(SDDWP)in Garhwal Himalaya
2
作者 Vishwambhar Prasad SATI 《Regional Sustainability》 2024年第2期140-152,共13页
With the population growth through natural growth and migration,coupled with the city expansion,it is the fact that Dehradun City in India faces severe water scarcity.Therefore,the Song Dam Drinking Water Project(SDDW... With the population growth through natural growth and migration,coupled with the city expansion,it is the fact that Dehradun City in India faces severe water scarcity.Therefore,the Song Dam Drinking Water Project(SDDWP)is proposed to provide ample drinking water to Dehradun City and its suburban areas.This paper examined economic significance and environmental impacts of the SDDWP in Garhwal Himalaya,India.To conduct this study,we collected data from both primary and secondary sources.There are 12 villages and 3 forest divisions in the surrounding areas of the proposed dam project,of which 3 villages will be fully submerged and 50 households will be affected.For this study,50 heads of the households were interviewed in the 3 submerged villages.The questions mainly focused on economic significance,environmental impacts,and rehabilitation issues of the dam project.The findings of this study indicate that economic significance of the dam project is substantial,including providing ample water for drinking and irrigation,contributing to groundwater recharge,creating job opportunities,and promoting the development of tourism and fisheries in the Doon Valley.In terms of the rehabilitation of the affected people,there are only 50 households in need of rehabilitation.Currently,the arable land of these affected people is not sufficient to sustain their livelihoods.The entire landscape is fragile,rugged,and precipitous;therefore,the affected people are willing to rehabilitate to more suitable areas in the Doon Valley.Moreover,it is essential to provide them with sufficient compensation packages including the compensation of arable land,houses,cash,common property resources,institutions,belongingness,and cultural adaptation.On the other hand,the proposed dam project will have adverse environmental impacts including arable land degradation,forest degradation,loss of fauna and flora,soil erosion,landslides,and soil siltation.These impacts will lead to the ecological imbalances in both upstream and downstream areas.This study suggests that the affected people should be given sufficient compensation packages in all respects.Afforestation programs can be launched in the degraded areas to compensate for the loss of forest in the affected areas. 展开更多
关键词 Water scarcity Rehabilitation issues Song Dam Drinking Water Project(SDDWP) Dehradun City Song River BASIN
下载PDF
Synergistic Contribution of Precipitation Anomalies over Northwestern India and the South China Sea to High Temperature over the Yangtze River Valley 被引量:8
3
作者 LIU Ge WU Renguang +1 位作者 SUN Shuqing WANG Huimei 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第9期1255-1265,共11页
This study explores the characteristics of high temperature anomalies over eastern China and associated influencing factors using observations and model outputs.Results show that more long-duration(over 8 days) high... This study explores the characteristics of high temperature anomalies over eastern China and associated influencing factors using observations and model outputs.Results show that more long-duration(over 8 days) high temperature events occur over the middle and lower reaches of the Yangtze River Valley(YRV) than over the surrounding regions,and control most of the interannual variation of summer mean temperature in situ.The synergistic effect of summer precipitation over the South China Sea(SCS) region(18°–27°N,115°–124°E) and the northwestern India and Arabian Sea(IAS) region(18°–27°N,60°–80°E) contributes more significantly to the variation of summer YRV temperature,relative to the respective SCS or IAS precipitation anomaly.More precipitation(enhanced condensational heating) over the SCS region strengthens the western Pacific subtropical high(WPSH) and simultaneously weakens the westerly trough over the east coast of Asia,and accordingly results in associated high temperature anomalies over the YRV region through stimulating an East Asia–Pacific(EAP) pattern.More precipitation over the IAS region further adjusts the variations of the WPSH and westerly trough,and eventually reinforces high temperature anomalies over the YRV region.Furthermore,the condensational heating related to more IAS precipitation can adjust upper-tropospheric easterly anomalies over the YRV region by exciting a circumglobal teleconnection,inducing cold horizontal temperature advection and related anomalous descent,which is also conducive to the YRV high temperature anomalies.The reproduction of the above association in the model results indicates that the above results can be explained both statistically and dynamically. 展开更多
关键词 high temperature events Yangtze River Valley precipitation ECHAM5
下载PDF
Detecting the Origins of Moisture over Southeast China:Seasonal Variation and Heavy Rainfall 被引量:5
4
作者 Xiuzhen LI Wen ZHOU Yongqin David CHEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第3期319-329,共11页
To examine the ability of the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to detect the origins and paths of moisture supplied to Southeast China, trajectories of air particles released o... To examine the ability of the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to detect the origins and paths of moisture supplied to Southeast China, trajectories of air particles released over Southeast China were traced backward during 1 April 2012 to 31 March 2013 and three typical regional persistent heavy rainfall events. The HYSPLIT model provides more insightful information than water vapor flux. Analysis of the specific humidity along the trajectories revealed the origins of moisture and their contributions to the moisture supply in Southeast China. In the boreal summer half year, four key moisture transport paths from the eastern Indian Ocean, central Indian Ocean, South China Sea (SCS), and western North Pacific (WNP) contribute 10%, 20%, 31%, and 16% of the moisture to Southeast China, respectively. In the winter half year, the contributions of the paths from the WNP and North China double. Examination of heavy rainfall events showed that under tropical storm conditions, all moisture transport routines are rotated cyclonically before reaching Southeast China. The invasion of cold air can trigger heavy rainfall in both the summer and winter half years but plays different roles: it does not contribute to the moisture supply but plays a key role in converging and uplifting the moisture in the summer half year, while it supplies a great amount of moisture in the winter half year as it absorbs abundant moisture in crossing the WNE 展开更多
关键词 moisture origin Southeast China HYSPLIT seasonal variation heavy rainfall
下载PDF
Changing Spatial and Structural Patterns of Non-agricultural Activities in Outward-moving Beijing Urban Fringe 被引量:3
5
作者 CAO Guangzhong LIU Tao +1 位作者 LIU Hui MIAO Yangbing 《Chinese Geographical Science》 SCIE CSCD 2012年第6期718-729,共12页
As responses to metropolitan suburbanization and rural urbanization,the formation and evolution of urban fringes should be understood against the background of overall economic development and spatial reconstruction o... As responses to metropolitan suburbanization and rural urbanization,the formation and evolution of urban fringes should be understood against the background of overall economic development and spatial reconstruction of entire metropolises.At the same time,however,endogenous interactions between industrial structure and spatial patterns of non-agricultural activities are also worthy of scholarly attention.Since the 1980s,studies on urban fringes in China have been restricted by the lack of micro-level data.This paper investigates the spatial expansion and structural evolution of the urban fringe by taking the case of Beijing and uses systematic firm-level data in 1996 and 2001 from the National Census of Basic Units.The diversity of distribution patterns across industrial sectors brings about two interrelated results.On the one hand,structural adjustment of non-agricultural industries promotes the expansion and spatial evolution of the urban fringe.On the other hand,the stability and dynamics of industrial structure coexist in the moving urban fringe.This study also reveals that the outward-moving urban fringe is the optimal location for manufacturing,especially heavy manufacturing,as well as traditional producer and consumer services.However,industries with spatial stickiness such as tourism and sports have not moved with the fringe.Most advanced services remain concentrated in the city center.The authors argue that it is essential for understanding and managing urban fringes to take into account spatial evolution and industrial structural adjustment together with their interaction with each other. 展开更多
关键词 urban fringe industrial structure spatial evolution SUBURBANIZATION BEIJING China
下载PDF
Relationships of exponents in multifractal detrended fluctuation analysis and conventional multifractal analysis 被引量:2
6
作者 周煜 梁怡 喻祖国 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第9期98-106,共9页
Multifractal detrended fluctuation analysis (MF-DFA) is a relatively new method of multifractal analysis. It is extended from detrended fluctuation analysis (DFA), which was developed for detecting the long-range ... Multifractal detrended fluctuation analysis (MF-DFA) is a relatively new method of multifractal analysis. It is extended from detrended fluctuation analysis (DFA), which was developed for detecting the long-range correlation and the fractal properties in stationary and non-stationary time series. Although MF-DFA has become a widely used method, some relationships among the exponents established in the original paper seem to be incorrect under the general situation. In this paper, we theoretically and experimentally demonstrate the invalidity of the expression r(q) = qh(q) - 1 stipulating the relationship between the multifractal exponent T(q) and the generalized Hurst exponent h(q). As a replacement, a general relationship is established on the basis of the universal multifractal formalism for the stationary series as .t-(q) = qh(q) - qH - 1, where H is the nonconservation parameter in the universal multifractal formalism. The singular spectra, a and f(a), are also derived according to this new relationship. 展开更多
关键词 fractals Hurst exponent multifractal detrended fluctuation analysis time series analysis
下载PDF
On the Temporal and Spatial Structure of Troposphere-toStratosphere Transport in the Lowermost Stratosphere over the Asian Monsoon Region during Boreal Summer 被引量:1
7
作者 陈斌 徐祥德 +1 位作者 杨帅 张伟 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第6期1305-1317,共13页
This study produced a novel characterization of the troposphere-to-stratosphere transport (TST) over the Asian monsoon region during boreal summer, using a comprehensive analysis of 60-day backward trajectories init... This study produced a novel characterization of the troposphere-to-stratosphere transport (TST) over the Asian monsoon region during boreal summer, using a comprehensive analysis of 60-day backward trajectories initialized in the stratosphere. The trajectory datasets were derived from the high-resolution Lagrangian particle dispersion model (FLEXPART) simulation driven by the wind fields acquired from the National Center for Environmental Prediction (NCEP). The results indicate that the distribution of residence time (tTST) of tropopause-crossing trajectories in the lowermost stratosphere represents a horizontal signature of the Asian summer monsoon. Vertically, the distribution of tTST can be roughly separated into two layers: a consistent lower layer with tTST 〈5 days forming a narrow band, corresponding to a layer-3 km thick following the location of the tropopause, and an upper layer at a larger distance from the local tropopause. The maximum residence time was -20 days, especially within the Asian high anticyclone consistent with its confinement effects. In general, the overall geographical distribution of dehydration points was not coincident with the location of tropopause crossing. TST trajectories, which were initialized in the stratosphere, underwent their Lagrangian cold points mostly in the tropics and subtropics 1 4 days after the TST event; they were characterized by a wide range of temperature differences, with a mean value of 3-12 K. The vertical extent of the influence of tropospheric intrusion on the Asian monsoon region in the stratosphere exhibited a peak at -16.5-18.5 km, and the uppermost height was -21 km. 展开更多
关键词 troposphere-to-stratosphere-transport Asian summer monsoon lower stratosphere structure
下载PDF
Managing wetlands:an ecological economic analysis of the Hong Kong Wetland Park 被引量:2
8
作者 Claudio O.Delang Tse Yuk Ling 《Ecological Economy》 2008年第4期440-453,共14页
This paper addresses the question of whether the Hang Kong government made a rational economic decision when it decided to set aside land to develop a Wetland Park, or whether it should have used the land for alternat... This paper addresses the question of whether the Hang Kong government made a rational economic decision when it decided to set aside land to develop a Wetland Park, or whether it should have used the land for alternative commercial developments. Different analytical methods are used to estimate the economic value of the environmental benefits of the Wetland Park: the Value Transfer Method is used to estimate the economic value oJ the ecological services provided by the Park. the Direct Market Price analysis for the economic value of the goods purchased in the Wetland Park, the Hedonic Housing Price Analysis for the value of the Park to those residing in its proximity, the Travel Cost and Contingent Valuation Method for the value of the Park to the visitors, and the Contingent Valuation for the Passive (Nonuse) Values of the Park. These benefits are compared to the opportunity cost of the land and the cost of running the Wetland Park. The article concludes that if a rate of 5% or less is used to discount fiture costs and benefits, we would find that the government's decision to set aside land for a Wetland Park was economically sound while using a discount rate of 6% or more shows that it was not. 展开更多
关键词 Wetland Park Hong Kong Total economic value Ecosystem services
下载PDF
Extreme Weather Related Disasters: A Case Study of Two Flashfloods Hit Areas of Badrinath and Kedarnath Valleys, Uttarakhand Himalaya, India
9
作者 Vishwambhar Prasad Sati 《Journal of Earth Science and Engineering》 2013年第8期562-568,共7页
Climate induced disasters such as cloudburst triggered flash floods, debris-flow, mass movements and landslides are very common phenomenon in the Himalaya. There are many instances in the recent past when these catast... Climate induced disasters such as cloudburst triggered flash floods, debris-flow, mass movements and landslides are very common phenomenon in the Himalaya. There are many instances in the recent past when these catastrophes caused heavy losses to lives and tremendous damage to property. One of the important characteristics of the Himalaya during the monsoon season is heavy downpour (cloudburst) which is due to extreme weather condition. Further, the landscape is very fragile and the human settlements are located either along the perennial streams of big rivers or on the unstable slopes. These perennial streams and big rivers are highly violent during the monsoon and whenever, the water level of these streams rises, it causes heavy loss to property and lives through destruction of the human settlements located along these courses. During the recent past, extreme changes in the climatic conditions have been seen largely due to the anthropogenic activities, i.e., population growth and large-scale deforestation. It has not only affected the climatic conditions but also affected the daily life of the inhabitants. This article examines the extreme weather related disasters in the Himalaya and gives a description of two deadly cloudburst triggered flashfloods that occurred in the Kedarnath and Badrinath valleys, which left the entire landscape devastated. This was followed by devastation of the settlements, agricultural fields, and thousands of lives were wiped out during this catastrophe. Rainfall data were collected to know about the changes in the climatic conditions and their impacts on the disaster in this part of the Himalaya. 展开更多
关键词 Climate disaster cloudburst SETTLEMENT DEFORESTATION Himalaya.
下载PDF
The Pioneering Works of Professor Duzheng YE on Atmospheric Dispersion,Tibetan Plateau Meteorology,and Air–Sea Interaction
10
作者 Ngar-Cheung LAU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第10期1137-1149,共13页
This paper provides an overview of the impacts of the original works of Professor Duzheng YE on a selected set of observational and model studies with which the present author has been associated over the past several... This paper provides an overview of the impacts of the original works of Professor Duzheng YE on a selected set of observational and model studies with which the present author has been associated over the past several decades. The main themes of these works include atmospheric energy dispersion, air–land interactions over the Tibetan Plateau, and El Ni n?orelated air–sea coupling over East Asia.The dispersive behavior of observed atmospheric fluctuations accompanying cold surge events in East Asia is demonstrated. Cold air outbreaks over Korea and southern China are coincident with the successive downstream development of troughs and ridges, with the group velocity of such wave packets being notably faster than the phase propagation speed of individual troughs and ridges. In a more general context, dispersive features are also discernible from lagged teleconnection charts and cross-spectra of observed and model-simulated geopotential height variations on 10–30-day time scales.Using the output from a high-resolution general circulation model, the relative contributions of condensational, sensible, and radiative heating to the atmospheric energy budget over the Tibetan Plateau are documented. The rapid changes of the upper tropospheric Tibetan anticyclone and East Asian mei-yu("plum rain") precipitation band associated with the development of the Asian monsoon system are described.The principal anomalies in sea level pressure, surface wind, precipitation and sea surface temperature over southeastern China and the Philippine Sea region during El Nio events are presented. The contributions of remote El Nio-related forcing and local air–sea interaction to the occurrence of these anomalies are assessed. 展开更多
关键词 atmospheric dispersion Tibetan Plateau meteorology El Nio
下载PDF
Examining the characteristics between time and distance gaps of secondary crashes
11
作者 Xinyuan Liu Jinjun Tang +2 位作者 Chen Yuan Fan Gao Xizhi Ding 《Transportation Safety and Environment》 EI 2024年第1期116-131,共16页
Understanding the characteristics of time and distance gaps between the primary(PC)and secondary crashes(SC)is crucial for preventing SC ccurrences and improving road safety.Although previous studies have tried to ana... Understanding the characteristics of time and distance gaps between the primary(PC)and secondary crashes(SC)is crucial for preventing SC ccurrences and improving road safety.Although previous studies have tried to analyse the variation of gaps,there is limited evidence in quantifying the relationships between different gaps and various influential factors.This study proposed a two-layer stacking framework to discuss the time and distance gaps.Specifically,the framework took random forests(RF),gradient boosting decision tree(GBDT)and eXtreme gradient boosting as the base classifiers in the first layer and applied logistic regression(LR)as a combiner in the second layer.On this basis,the local interpretable model-agnostic explanations(LIME)technology was used to interpret the output of the stacking model from both local and global perspectives.Through SC dentification and feature selection,346 SCs and 22 crash-related factors were collected from California interstate freeways.The results showed that the stacking model outperformed base models evaluated by accuracy,precision,and recall indicators.The explanations based on LIME suggest that collision type,distance,speed and volume are the critical features that affect the time and distance gaps.Higher volume can prolong queue length and increase the distance gap from the SCs to PCs.And collision types,peak periods,workday,truck involved and tow away likely induce a long-distance gap.Conversely,there is a shorter distance gap when secondary roads run in the same direction and are close to the primary roads.Lower speed is a significant factor resulting in a long-time gap,while the higher speed is correlated with a short-time gap.These results are expected to provide insights into how contributory features affect the time and distance gaps and help decision-makers develop accurate decisions to prevent SCs. 展开更多
关键词 secondary crash(SC) time and distance gaps stacking framework local interpretable model-agnostic explanations(LIME)
原文传递
Channel changes of the Makou-Tianjiazhen reach in the middle Yangtze River during the past 40 years 被引量:3
12
作者 ZHANG Qiang CHEN Yongqin David +1 位作者 JIANG Tong LI Maotian 《Journal of Geographical Sciences》 SCIE CSCD 2007年第4期442-452,共11页
Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate tha... Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate that the river reach between Makou and Tianjiaz- hen was dominated by the scouring process, and the magnitude of scouring is increasing over time. The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones. The river reach in the Makou and Tianjiazhen river knot is in frequent scouring and filling process, however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process. The river reach just upstream or downstream to the river knot (e.g. Makou and Tianjiazhen river knot in this research) is dominated by filling process and the river reach in the river knot is dominated by the scouring process. Research results indicate no changes in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong. The filling and the scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach. The construction of the Three Gorges Dam just up- stream to Yichang will cause further decrease of the release of the sediment load to the middle and the lower Yangtze River basin, which will further intensify the scouring process of the river channel in the study river reach. 展开更多
关键词 Makou-Tianjiazhen river reach GIS DEM river channel changes
下载PDF
MAGE ANALYSIS OF GEOSTATIONARY METEOROLOGICAL SATELLITE FOR MONITORING MOVEMENT OF MESOSCALE CONVECTIVE SYSTEMS OVER TIBETAN PLATEAU 被引量:1
13
作者 DAI Xiao-yan WU Jian-ping LIN Hui 《Chinese Geographical Science》 SCIE CSCD 2005年第3期231-237,共7页
Disaster weather forecasting is becoming increasingly important. In this paper, the trajectories of Mesoscale Convective Systems (MCSs) were automatically tracked over the Chinese Tibetan Plateau using Geostationary... Disaster weather forecasting is becoming increasingly important. In this paper, the trajectories of Mesoscale Convective Systems (MCSs) were automatically tracked over the Chinese Tibetan Plateau using Geostationary Meteorological Satellite (GMS) brightness temperature (Tbb) from June to August 1998, and the MCSs are classified according to their movement direction. Based on these, spatial data mining methods are used to study the relationships between MCSs trajectories and their environmental physical field values. Results indicate that at 400hPa level, the trajectories of MCSs moving across the 105°E boundary are less influenced by water vapor flux divergence, vertical wind velocity, reIative humidity and K index. In addition, if the gravity central longitude locations of MCSs are between 104°E and 105°E, then geopotential height and wind divergence are two main factors in movement causation. On the other hand, at 500hPa level, the trajectories of MCSs in a north-east direction are mainly influenced by K index and water vapor flux divergence when their central locations are less than 104°E. However, the MCSs moving in an east and south-east direction are influenced by a few correlation factors at this level. 展开更多
关键词 Tibetan Plateau Mesoscale Convective Systems automatically tracking spatial data mining
下载PDF
ANALYSIS OF MESOSCALE CONVECTIVE SYSTEMS OVER TIBETAN PLATEAU IN SUMMER 被引量:1
14
作者 GUO Zhong-yang DAI Xiao-yan +1 位作者 WU Jian-ping LIN Hui 《Chinese Geographical Science》 SCIE CSCD 2006年第2期116-121,共6页
In this paper, Geostationary Meteorological Satellite (GMS) infrared black-body temperature (Tbb) data from June to August 1998 are used to automatically track the activity of Mesoscale Convective System (MCS) over th... In this paper, Geostationary Meteorological Satellite (GMS) infrared black-body temperature (Tbb) data from June to August 1998 are used to automatically track the activity of Mesoscale Convective System (MCS) over the Tibetan Plateau in China. Consequently, the features of MCS, such as area, intensity, life cycle, activity region and shape, are obtained. High Resolution Limited Area Analysis and Forecasting System (HLAFS) values provided by China National Meteorological Center are used to study the relationships between the MCS trajectories and their environmental physical field values, based on the distribution and trajectories of MCSs over the Tibetan Plateau. Favorable environmental physical field charts of influencing MCS movement out of the Tibetan Plateau in different UTC (Universal Time Coordinate) are developed by using spatial data mining techniques at levels of 400hPa and 500hPa, respectively. 展开更多
关键词 Tibetan Plateau Mesoscale Convective Systems black-body temperature automatically tracking
下载PDF
Geodiversity and Geoconservation in Hong Kong
15
作者 Saileung NG Young C.Y.NG 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期38-38,共1页
Geodiversity refers to the diversity(or variety, range) of geological(rocks,minerals,fossils),geomorphological (landform) and soil features,and their assemblages,relationships,processes,properties, interpretations and... Geodiversity refers to the diversity(or variety, range) of geological(rocks,minerals,fossils),geomorphological (landform) and soil features,and their assemblages,relationships,processes,properties, interpretations and systems.Despite there is a limited area of 1108 km^2,Hong Kong has a remarkably rich geodiversity that includes diversified geology, landforms,and assemblages of associated features and processes.Some geological features can even 展开更多
关键词 GEOCONSERVATION GEODIVERSITY geo-park Hong Kong
下载PDF
The new economy of nature:can carbon pay for nature conservation? The case of the Hong Kong Country Parks
16
作者 Claudio O.DELANG 《Ecological Economy》 2010年第2期115-130,共16页
The Country Parks of Hong Kong occupy 40%of the total landmass of Hong Kong,and consists of vast areas of secondary woodlands,scrublands,grasslands,and reservoirs.That vegetation-and the soil underneathsubtract carbon... The Country Parks of Hong Kong occupy 40%of the total landmass of Hong Kong,and consists of vast areas of secondary woodlands,scrublands,grasslands,and reservoirs.That vegetation-and the soil underneathsubtract carbon from the atmosphere,which has a market value.The aim of this paper is to estimate the value of that carbon,to assess whether that value would be sufficient to pay for the upkeep of the Country Parks,and to compare that value to the costs of alternative ways to reduce atmospheric carbon dioxide.To do this,we compare the land cover of 1978,1991,1997 and 2004 using remote sensing,and identify the three predominant land covers(woodlands,scrublands,grasslands) .We then estimate the amount and value of the carbon sequestered by the vegetation and soil of the Country Parks,and compare it to the budget available to the Agriculture,Fisheries and Conservation Department to run the Country Parks(HK$234 million in 2009/2010) .We extrapolate our results over 50 years,from 1978 to 2028.We conclude that by 2028 the carbon sequestered would be valued over HK$800 million,but the value of the additional carbon subtracted yearly would only cover approximately 7%of the total budget needed to run the Country Parks.We also conclude that because of the large budget allocated to the Country Parks,alternative methods of carbon sequestration-represented by the EU ETS price of carbon-are much cheaper. 展开更多
关键词 Hong Kong Country Parks Protected areas Carbon sequestration Carbon credits
下载PDF
Amelioration of habitat since the early Holocene contributed to the origin of agriculture in the farming-pastoral zone of northern China
17
作者 Xin JIA Zhiping ZHANG +11 位作者 Yonggang SUN Runqi JIANG Shuangwen YI Wei CHEN Jue SUN Guoqiang LI Shuzhi WANG Enrui LI Xiaonong HU Qingchun BAO Harry F.LEE Huayu LU 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第8期2535-2546,共12页
The origin of agriculture in the farming-pastoral zone of northern China remains in dispute.The central region of the Inner Mongolia Plateau is located in the core area of the farming-pastoral zone;thus,it is a critic... The origin of agriculture in the farming-pastoral zone of northern China remains in dispute.The central region of the Inner Mongolia Plateau is located in the core area of the farming-pastoral zone;thus,it is a critical region for exploring the origin of the dryland farming system in northern China.This study selected the Yumin Site and Banan Site,which belong to the Yumin Culture-the beginning of Neolithic culture in Inner Mongolia-as the research objects.Based on the quartz optically stimulated luminescence(OSL)dating on the sedimentary sections from the Yumin site(YM)and Banan site(BN1 and BN2),the Holocene chronology framework of each section was established.After that,by identifying carbonized grains in the Yumin site and the multi-proxy analysis of each section,we investigated the relationship between the origin of agriculture and climate change in this region.The results revealed that the timing of the origin of agriculture recorded in the Yumin site lagged behind the timing of a significant increase of precipitation during the early Holocene but coincided with the timing of a significant increase of vegetation around 8.4 ka.This phenomenon was further confirmed by the published high-resolution paleoenvironmental records from the surrounding area of the Yumin Culture.We propose that with the gradual amelioration of hydrothermal conditions since the beginning of the Holocene,the regional ecosystem had been improved,resulting in the gradual conversion of the land surface from infertile sand to organic-rich soil,providing an appropriate environmental foundation for the origin of dryland farming in northern China around 8.4 ka.This study highlighted that the“accumulative environmental effects”during the early Holocene played a vital role in the origin of agriculture in northern China and provided a reference for agricultural management in the context of future climate change. 展开更多
关键词 Origin of agriculture Accumulative environmental effects Yumin Culture Northern China HOLOCENE
原文传递
Spatial patterns, driving forces, and urbanization effects of China's internal migration: County-level analysis based on the 2000 and 2010 censuses 被引量:24
18
作者 LIU Tao QI Yuanjing +1 位作者 CAO Guangzhong LIU Hui 《Journal of Geographical Sciences》 SCIE CSCD 2015年第2期236-256,共21页
China has witnessed unprecedented urbanization over the past decades. The rapid expansion of urban population has been dominantly contributed by the floating population from rural areas, of which the spatiotemporal pa... China has witnessed unprecedented urbanization over the past decades. The rapid expansion of urban population has been dominantly contributed by the floating population from rural areas, of which the spatiotemporal patterns, driving forces, and multidimensional effects are scrutinized and evaluated in this study by using the latest national censuses conducted in 2000 and 2010. Analysis based on the county-level data comes to conclusions as follows. The spatial pattern of floating population has remained stable over the first decade of the new century. The top 1% cities with the largest floating population received 45.5% of all migrants in China. As the rapid development of mega-city regions, the coastal concentration areas of floating population tended to geographically united as a whole, whereas the spatial distribution of migrants within each region varied significantly. The migrant concentration area in the Yangtze River Delta was the largest and its expansion was also the most salient. However, the floating population has growingly moved into provincial capitals and other big cities in the inland regions and its gravity center has moved northward for around 110 km during the study period. The spatial pattern of floating population has been formed jointly by the state and market forces in transitional China and the impacts of state forces have been surpassed by those of market forces in the country as a whole. The attractiveness of coastal cities and counties to the floating population comes mainly from the nonagricultural employment opportunities and public services, reflecting that long-distance and long-term migrants have moved coastward not only to gain employment but also to enjoy city life. By contrast, in the central and western regions, places with a higher economic development level and at a higher administrative level are more attractive to floating populations, demonstrating that the state remains to play an important role in allocating economic resources and promoting regional development in inland China. As the main body of new urban residents, the floating population has contributed substantially to the elevation of the urbanization levels of migrant-sending and -receiving places, by 20.0% and 49.5% respectively. Compared with ex- tensively investigated interprovincial migrants, intra-provincial migrants have higher intention and ability to permanently live in cities and thus might become the main force of China's urbanization in the coming decades. The internal migration has also reshaped China's urban system in terms of its hierarchical organization and spatial structure. 展开更多
关键词 floating population migration URBANIZATION urban system megacity region CENSUS China
原文传递
Effect of drainage on CO_2, CH_4, and N_2O fluxes from aquaculture ponds during winter in a subtropical estuary of China 被引量:14
19
作者 Ping Yang Derrick Y.F Lai +1 位作者 Jia F.Huang Chuan Tong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第3期72-82,共11页
Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the product... Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the production and flux of greenhouse gases(GHGs)from aquaculture ponds are largely unknown.In the present study,field-based research was performed to compare the GHG fluxes between one drained pond(DP,with a water depth of 0.05 m)and one undrained pond(UDP,with a water depth of 1.16 m)during one winter in the Min River estuary of southeast China.Over the entire study period,the mean CO2flux in the DP was(0.75±0.12)mmol/(m^2·hr),which was significantly higher than that in the UDP of(-0.49±0.09)mmol/(m^2·hr)(p0.01).This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in winter.Mean CH4and N2O emissions were significantly higher in the DP compared to those in the UDP(CH4=(0.66±0.31)vs.(0.07±0.06)mmol/(m^2·hr)and N2O=(19.54±2.08)vs.(0.01±0.04)μmol/(m^2·hr))(p〈0.01),suggesting that drainage would also significantly enhance CH4and N2O emissions.Changes in environmental variables(including sediment temperature,p H,salinity,redox status,and water depth)contributed significantly to the enhanced GHG emissions following pond drainage.Furthermore,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP(p〈0.01),with values of739.18 and 26.46 mg CO2-eq/(m^2·hr),respectively.Our findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming. 展开更多
关键词 Aquaculture pond Drainage management Greenhouse gas flux Global warming Min River estuary
原文传递
Nitrogen Mineralization in Soils Along a Vegetation Chronosequence in Hong Kong 被引量:5
20
作者 L.M.MARAFA K.C.CHAU 《Pedosphere》 SCIE CAS CSCD 2005年第2期181-188,共8页
This research examined nitrogen mineralization in the top 10 cm of soils along a vegetation gradient in Hong Kong at sites where fire has been absent for 0, 1, 3, 6 and 17 years (at the time of the study), and the rel... This research examined nitrogen mineralization in the top 10 cm of soils along a vegetation gradient in Hong Kong at sites where fire has been absent for 0, 1, 3, 6 and 17 years (at the time of the study), and the relationships between N mineralization and successional development of vegetation in the absence of fire. The sites including a newly burnt area (S1), short grassland (S2), tall grassland (S3), mixed tall grassland and shrubland (S4), and woodland (S5) were selected,and the in situ core incubation method was used to estimate nitrogen mineralization. Throughout the 60-day incubation in four periods, more nitrogen was mineralized at the S3 and S4 sites, the predominantly grassland sites, which contained the highest levels of soil organic matter (SOM) and total Kjeldahl nitrogen (TKN), than the S1 site, while immobilization occurred at the S2 and S5 sites. Leaching loss decreased with successional development of the vegetation, in the order of S1 > S2 > S3 > S4 > S5. The pattern of nitrogen uptake with ecological succession was less conspicuous, being complicated by the immediate effect of fire and possibly the ability of the woodland species to extract nitrogen from the deeper ground.In the absence of fire for 3 to 6 years, the build-up of SOM and TKN was accompanied by active mineralization, thus paving the way for the invasion of shrub and tree species. A close relationship existed between nitrogen mineralization and ecological succession with this vegetation gradient. Inherent mechanisms to preserve nitrogen in a fire-prone environment including immobilization and uptake and the practical relevance of nitrogen mineralization to reforestation are discussed. 展开更多
关键词 fire impact IMMOBILIZATION nitrogen mineralization successional development vegetation chronosequence
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部