期刊文献+
共找到7,677篇文章
< 1 2 250 >
每页显示 20 50 100
An Economic Analysis of Iraq’s Role in International Climate Change Agreements Using SWOT Analysis
1
作者 Zeena Sabah Noori A.D.K AL-Hiyali 《Journal of Environmental & Earth Sciences》 2025年第4期291-308,共18页
The research aims to analyze the most important contributions made by Iraq and its role in global conferences and agreements that dealt with climate change,using SWOT analysis for the purpose of determining Iraq’s vi... The research aims to analyze the most important contributions made by Iraq and its role in global conferences and agreements that dealt with climate change,using SWOT analysis for the purpose of determining Iraq’s vision in confronting climate change until the year 2030.In addition to learning about the legal steps taken by Iraq to confront climate change through legal issuances and legislation that guarantee the protection of the Iraqi environment.Through SWOT analysis,the research found that the areas of strength were represented by 23 points,the most important of which were its contributions to signing international agreements to reduce climate impacts,strengthening environmental investment methods in waste management.The weaknesses were represented by 16 points,the most important of which were the decrease in vegetation areas,high temperatures,and low awareness of climate change.Iraq faces many opportunities represented by 8 opportunities to improve the response to climate change,the most important of which is the environmental location that characterizes Iraq,as well as the renewal of damaged agricultural lands.While there were 21 threats,the most serious of which were desertification,dust storms,and dust.The research recommends taking advantage of areas of strength and opportunities to reduce weaknesses and threats,for the purpose of determining the future steps of the strategic plans for Iraq. 展开更多
关键词 SWOT analysis Climate change SUSTAINABILITY Environmental Investment
在线阅读 下载PDF
Response of Ecosystem Service Value Based on Land Use Changes and Analysis of its Driving Factors in Typical Hilly Region with Red Soil 被引量:6
2
作者 邹金浪 王金政 +1 位作者 王鹏 乐文年 《Agricultural Science & Technology》 CAS 2010年第11期150-154,共5页
The contribution rate of ecosystem service value variation was used to analyze the effects of land use changes on the changes of ecosystem service value in Xingguo County during 1996-2005.Grey integrated correlation w... The contribution rate of ecosystem service value variation was used to analyze the effects of land use changes on the changes of ecosystem service value in Xingguo County during 1996-2005.Grey integrated correlation was employed to explore the contribution level of the indicators such as total population,urbanization level,proportion of primary industry and investment of social fixed assets on ecosystem service value,and the correlation analysis was also carried out.The results showed that the ecosystem service value in Xingguo County during 1996-2005 mainly was woodland,and the decrease of woodland area was the major reason for the sustained reduction of ecosystem service value.With the further increase of market demand and the incentives of local government,the garden area rapidly increased during 2001-2005,and the influence degree of garden towards the changes of ecosystem service value was only second to woodland,ranking No.2.Four socio-economic indicators had different correlation degree with ecosystem service value during the different research periods.Total population,urbanization level and proportion of primary industry had high correlation degree with ecosystem service value,whereas the influence degree of various socio-economic indicators on ecosystem service value was equal with each other day by day.Urbanization level,investment of social fixed assets and total population had significant negative correlation with ecosystem service value,while the proportion of primary industry had positive correlation with ecosystem service value. 展开更多
关键词 Ecosystem service value Land use change Gray correlation analysis Driving factor Hilly region with red soil
在线阅读 下载PDF
Geo-information Tupu Analysis of Land Use Change in Haihe River Basin 被引量:2
3
作者 朱占永 郭伟志 张海力 《Agricultural Science & Technology》 CAS 2012年第5期1139-1144,共6页
[Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin (HRB) through the quantitative exploration of the land use conversion, changes of intensity and spatial dist... [Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin (HRB) through the quantitative exploration of the land use conversion, changes of intensity and spatial distribution in this region. [Method] With the support of remote sensing technology and geographic information technology, the land use maps of the study area in 40 years (1970-2010) were in- terpreted and plotted. Four kinds of tupu, namely, land use change tupu, process tupu, arising tupu and evolution mode tupu were built through the spatial overlay of the land use maps to analyze the change rules of land use patterns. [Result] The conversion of arable land to construction land was the main characteristics of land use changes in HRB for the 40 years; the area of non-stable region accounted for 35% of the total, indicating that the land use changed remarkably, thus, it was nec- essary to strengthen the scientific land management in HRB; the new conversions to all land use patterns were all the lowest in 1980-1990, indicating that land use changed slowly during this period. [Conclusion] The results indicate that, compared with conventional transfer matrix method, geo-information tupu has obvious advantage in analyzing land use changes that it can demonstrate the spatial distribution of interest region, display the multi-dimensional spatial information. 展开更多
关键词 Haihe river basin Tupu analysis Land use change Evolution mode
在线阅读 下载PDF
Climate and human drivers of surface water changes in the Zavkhan River-Khyargas Lake Basin,western Mongolia
4
作者 BATSUREN Dorjsuren VALERY A.Zemtsov +4 位作者 ERDENEBAYAR Bavuu SANDELGER Dorligjav YAN Denghua GAO Hongkai ALTANBOLD Enkhbold 《Journal of Geographical Sciences》 2026年第1期255-280,共26页
This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis... This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence. 展开更多
关键词 arid zone semi-arid zone climate change land cover trend analysis western Mongolia
原文传递
Historical Changes of Ningxia Natural Disasters and Its Reason Analysis 被引量:1
5
作者 丁建军 冯建民 +1 位作者 梁旭 陈晓娟 《Meteorological and Environmental Research》 CAS 2010年第12期67-70,81,共5页
A quantitative model is built and the historical variation of natural disasters is analyzed in this paper,by using materials as affected area(damaged area),affected population(dead and injured),casualty of livestock,c... A quantitative model is built and the historical variation of natural disasters is analyzed in this paper,by using materials as affected area(damaged area),affected population(dead and injured),casualty of livestock,collapsed houses(damaged houses),decrease of crops yield,economic loss(direct and indirect) and price index over the same period of Ningxia natural disasters(include drought,flood,gale and hail,frost,pest disasters and other disasters) during 1978-2007,and applying gray correlation analysis method.The long-term changes trend of natural disasters is analyzed by the application of the least squares method for linear trend,and the oscillation period is analyzed by using the maximum entropy statistical method.It is found that natural disasters have basically 2 to 3 years of variation period either in the whole region or in the individual regions;from the mid 1980s to the late 1990s,Ningxia is in an oscillation period with disasters attacked frequently in decadal and interannual scale under the background of climate;the increase of damage intensity of natural disasters slow down and tends to decrease since 2000. 展开更多
关键词 Ningxia Natural disasters Historical changes Reason analysis China
在线阅读 下载PDF
Temperature variation and abrupt change analysis in the Three-River Headwaters Region during 1961-2010 被引量:9
6
作者 Yi Xiangsheng Li Guosheng Yin Yanyu 《Journal of Geographical Sciences》 SCIE CSCD 2012年第3期451-469,共19页
In this study, a monthly dataset of temperature time series (1961-2010) from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province (THRHR) was used to analyze the climate change. T... In this study, a monthly dataset of temperature time series (1961-2010) from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province (THRHR) was used to analyze the climate change. The temperature variation and abrupt change analysis were examined by using moving average, linear regression, Spline interpolation, Mann-Kendall test and so on. Some important conclusions were obtained from this research, which mainly contained four aspects as follows. (1) There were several cold and warm fluctuations for the annual and seasonal average temperature in the THRHR and its three sub-headwater regions, but the temperature in these regions all had an obviously rising trend at the statistical significance level, especially after 2001. The spring, summer, autumn and annual average temperature increased evidently after the 1990s, and the winter average temperature exhibited an obvious upward trend after entering the 21st century. Except the standard value of spring temperature, the annual and seasonal temperature standard value in the THRHR and its three sub-headwater regions increased gradually, and the upward trend for the standard value of winter average temperature indicated significantly. (2) The tendency rate of annual average temperature in the THRHR was 0.36℃ 10a^-1, while the tendency rates in the Yellow River Headwater Region (YERHR), Lancangjiang River Headwater Region (LARHR) and Yangtze River Headwater Region (YARHR) were 0.37℃ 10a^-1, 0.37℃ 10a^-1 and 0.34℃10a^-1 respectively. The temperature increased significantly in the south of Yushu County and the north of Nangqian County. The rising trends of temperature in winter and autumn were higher than the upward trends in spring and summer. (3) The abrupt changes of annual, summer, autumn and winter average temperature were found in the THRHR, LARHR and YARHR, and were detected for the summer and autumn average temperature in the YERHR. The abrupt changes of annual and summer average temperatures were mainly in the late 1990s, while the abrupt changes of autumn and winter average temperatures appeared primarily in the early 1990s and the early 21st century respectively. (4) With the global warming, the diversities of altitude and underlying surface in different parts of the Tibetan Plateau were possibly the main reasons for the high increasing rate of temperature in the THRHR. 展开更多
关键词 temperature variation inter-annual change inter-decadal change standard value change abruptchange analysis Three.River Headwaters Region
原文传递
A Comparative Analysis of Evaporate Sediments on Earth and Mars: Implications for the Climate Change on Mars 被引量:8
7
作者 ZHENG Mianping KONG Weigang +2 位作者 ZHANG Xuefei CHEN Wenxi KONG Fanjing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第3期885-897,共13页
The knowledge of Martian salts has gone through substantial changes during the past decades. In the 70th of last century, Viking landers have noticed the existence of salts on Mars. Several salt species have been sugg... The knowledge of Martian salts has gone through substantial changes during the past decades. In the 70th of last century, Viking landers have noticed the existence of salts on Mars. Several salt species have been suggested from then on, such as sulfates and chlorides. However, their origin was a mystery due to the lack of observations. The recent explorations and related studies at the beginning of this century revealed that the crustal composition of Mars is similar to that of Earth, and it was hypothesized that almost one third of Martian surface was covered by oceans and lakes in the early stage of Mars. The huge water bodies may have dissolved a large quantity of ions from Martian primary rocks during the whole Noachian and Hesperian epoch. After the enormous drought event happened during the late Hesperian and the early Amazonian, these dissolved ions have formed huge salts deposits and most of them were preserved on Mars until today. To date, carbonates, sulfates, chlorides have all been detected by orbital remote sensing and by landers and rovers. However, the salt mineral assemblages on Mars seems to have some differences from those on Earth, e.g., rich in sulfates and lack of massive carbonates. To explain this difference, we propose that most of the surface carbonates precipitated from the ancient oceans may have been dissolved by the later ubiquitous acidic fluids originated from the global volcanism in the Hesperian era, and formed the enormous sulfate deposits as detected, and this hypothesis seems to be supported by the evidence that most of the sulfate deposits distribute around the Tharsis volcanic province while the survived carbonates located far from it. This process can release most of the carbon on Mars to the atmosphere in the form of CO2 and then be erased by the late heavy bombardments, which might have profound influence on the climate change happened in the Hesperian age. The positive correlation between the GRS results of the potassium distributions and the distribution of chlorides on Mars, together with the high Br concentration measured from the evaporate sediments at two Mars exploration rover landing sites, indicate that the brines in the regions where the chlorides deposited may have reached the stage for potassium salts deposition, thus we propose for the first time that potassium salts deposits might be prevalent in these regions. 展开更多
关键词 MARS evaporate sediments comparative analysis climate change potassium salts deposition
在线阅读 下载PDF
Land use change in Bohai Rim: a spatial-temporal analysis 被引量:7
8
作者 ZHU Hui-yi, LI Xiu-bin, HE Shu-jin, ZHANG Ming (Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China) 《Journal of Geographical Sciences》 SCIE CSCD 2001年第3期305-312,共8页
Based on RS and GIS methods, land use information for 1985 and 1995 was acquired from TM images and analyzed. Then on both spatial and temporal aspects, this paper analyzes land use change in three provinces of Hebei,... Based on RS and GIS methods, land use information for 1985 and 1995 was acquired from TM images and analyzed. Then on both spatial and temporal aspects, this paper analyzes land use change in three provinces of Hebei, Shandong and Liaoning and two municipalities of Beijing and Tianjin in the Bohai Rim covering the period of 1985 to 1995. The extent, rate, areal difference and trend of various types of land use changes in the region, as well as spatial changes of major types of land use, their distribution characteristics and regional orientation are revealed. The regional characteristics of land use are elaborated, so as to provide effective policy support for sustainable land use in the area around the Bohai Bay. 展开更多
关键词 Bohai Rim land use change spatio-temporal analysis
在线阅读 下载PDF
Wavelet Analysis and Nonparametric Test for Climate Change in Tarim River Basin of Xinjiang During 1959-2006 被引量:14
9
作者 XU Jianhua CHEN Yaning +3 位作者 LI Weihong JI Minhe DONG Shan HONG Yulian 《Chinese Geographical Science》 SCIE CSCD 2009年第4期306-313,共8页
Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tari... Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tarim River Basin of Xinjiang Uygur Autonomous Region,China.Major findings are as follows:1) In the 48-year study period,average annual temperature,annual precipitation and average annual relative humidity all presented nonlinear trends.2) At the 16-year time scale,all three climate indices unanimously showed a rather flat before 1964 and a detectable pickup thereafter.At the 8-year time scale,an S-shaped nonlinear and uprising trend was revealed with slight fluctuations in the entire process for all three indices.Incidentally,they all showed similar pattern of a slight increase before 1980 and a noticeable up-swing afterwards.The 4-year time scale provided a highly fluctuating pattern of periodical oscillations and spiral increases.3) Average annual relative humidity presented a negative correlation with average annual temperature and a positive correlation with annual precipitation at each time scale,which revealed a close dynamic relationship among them at the confidence level of 0.001.4) The Mann-Kendall test at the 0.05 confidence level demonstrated that the climate warming trend,as represented by the rising average annual temperature,was remarkable,but the climate wetting trend,as indicated by the rising annual precipitation and average annual relative humidity,was not obvious. 展开更多
关键词 climate change nonlinear trend wavelet analysis Mann-Kendall test Tarim River Basin
在线阅读 下载PDF
Comparative transcriptome analysis on the alteration of gene expression in ayu (Plecoglossus altivelis)larvae associated with salinity change 被引量:4
10
作者 Xin-Jiang LU Hao ZHANG +2 位作者 Guan-Jun YANG Ming-Yun LI Jiong CHEN 《Zoological Research》 CAS CSCD 2016年第3期126-135,共10页
Ayu (Plecoglossus altivelis) fish, which are an amphidromous species distributed in East Asia, live in brackish water (BW) during their larval stage and in fresh water (FW) during their adult stage. In this stud... Ayu (Plecoglossus altivelis) fish, which are an amphidromous species distributed in East Asia, live in brackish water (BW) during their larval stage and in fresh water (FW) during their adult stage. In this study, we found that FW-acclimated ayu larvae exhibited a slower growth ratio compared with that of BW-acclimated larvae. However, the mechanism underlying FW acclimation on growth suppression is poorly known. We employed transcriptome analysis to investigate the differential gene expression of FW acclimation by RNA sequencing. We identified 158 upregulated and 139 downregulated transcripts in FW-acclimated ayu larvae compared with that in BW-acclimated larvae. As determined by Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway mapping, functional annotation of the genes covered diverse biological functions and processes, and included neuroendo- crinology, osmotic regulation, energy metabolism, and the cytoskeleton. Transcriptional expression of several differentially expressed genes in response to FW acclimation was further confirmed by real-time quantitative PCR. In accordance with transcriptome analysis, iodothyronine deiodinase (ID), pro-opiom- elanocortin (POMC), betaine-homocysteine S-meth- yltransferase 1 (BHMT), fructose-bisphosphate aldolase B (aldolase B), tyrosine aminotransferase (TAT), and Na+-K+ ATPase (NKA) were upregulated after FW acclimation. Furthermore, the mRNA expressions of b-type natriurefic peptide (BNP) and transgelin were downregulated after FW acclimation. Our data indicate that FW acclimation reduced the growth rate of ayu larvae, which might result from the expression alteration of genes related to endocrine hormones, energy metabolism, and direct osmoregulation. 展开更多
关键词 Plecoglossus altivelis Salinity change Transcriptome analysis Growth rate Real-time quantitative PCR
在线阅读 下载PDF
NDVI changes in China between 1989 and 1999 using change vector analysis based on time series data 被引量:3
11
作者 Chen Yun-hao Li Xiao-bing Xie Feng 《Journal of Geographical Sciences》 SCIE CSCD 2001年第4期3-12,共10页
Change vector analysis (CVA) and principal component analysis in NDVI time-trajectories space are powerful tools to analyze land-cover change. The magnitude of the change vector indicates amplitude of the change, whil... Change vector analysis (CVA) and principal component analysis in NDVI time-trajectories space are powerful tools to analyze land-cover change. The magnitude of the change vector indicates amplitude of the change, while its direction indicates the nature of the change. CVA is applied to two remotely sensed indicators of land surface conditions, NDVI and spatial structure, in order to improve the capability to detect and categorize land-cover change. The magnitude and type of changes are calculated in China from 1989 to 1999. Through the research, the main conclusions are drawn as follows: 1) The changes of NDVI are quite different between eastern China and western China, and the change range in the east is bigger than that in the west. The trend in NDVI time series is smoothly increasing, the increases happen mostly in Taiwan, Fujian, Sichuan and Henan provinces and the decreases occur in Yunnan and Xinjiang. 2) The spatial structure index can indicate changes in the seasonal ecosystem dynamics for spatially heterogeneous landscapes. Most of spatial structure changes, which occurred in southern China, correlated with vegetation growth processes and strike of mountains. 展开更多
关键词 LAND-COVER NDVI change vector analysis spatial structure
在线阅读 下载PDF
Quantitative analysis of the dynamic change and spatial differences of the ecological security: a case study of Loess Plateau in northern Shaanxi Province 被引量:5
12
作者 LI Jing REN Zhiyuan ZHOU Zixiang 《Journal of Geographical Sciences》 SCIE CSCD 2006年第2期251-256,共6页
Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecologica... Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecological carrying capacity and ecological surplus/loss in 1986-2002 on the Loess Plateau in northern Shaanxi Province. What is more, this paper has put forward the concept of ecological pressure index, set up ecological pressure index models, and ecological security grading systems, and the prediction models of different ecological footprints, ecological carrying capacity, ecological surplus and ecological safety change, and also has assessed the ecological footprint demands of 10,000 yuan GDE The results of this study are as follows: (1) the ecological carrying capacity in northern Shaanxi shows a decreasing trend, the difference of reducing range is the fastest; (2) the ecological footprint appears an increasing trend; (3) ecological pressure index rose to 0.91 from 0.44 during 1986-2002 on the Loess Plateau of northern Shaanxi with an increase of 47%; and (4) the ecological security in the study area is in a critical state, and the ecological oressure index has been increasing rapidlv. 展开更多
关键词 regional ecological security dynamic change spatial difference quantitative analysis the Loess Plateau in northern Shaanxi Province
在线阅读 下载PDF
Analysis on Genomic Structure Changes and Diversity of Introgression Lines in Dongxiang Wild Rice(Oryza rufipogon Griff.)
13
作者 邓晓娟 罗向东 +4 位作者 谢建坤 万勇 胡标林 曹娟芳 戴亮芳 《Agricultural Science & Technology》 CAS 2012年第1期93-97,共5页
[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. ... [Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% (amplified by primer RM131) and the lowest was 60.25% (RM171). The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% (RM171) and the lowest was 2.93% (RM1095). There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%(RM401). Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% (RM311) and the lowest was 0 (RM401). The average rate of new bands was 1%. The average of Nei's gene di- versity (He) and Shannon's Information index (I) were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation. 展开更多
关键词 Oryza rufipogon Griff. Introgression lines SSR analysis Genomic structure changes Genetic variation
在线阅读 下载PDF
Remote Sensing &GIS Based Spatio-Temporal Change Analysis of Wetland in Dhaka City, Bangladesh 被引量:3
14
作者 Ummai Habiba Fouzia Haider +2 位作者 Asif Ishtiaque Mallik Sezan Mahmud Arif Masrur 《Journal of Water Resource and Protection》 2011年第11期781-787,共7页
Landscape of Dhaka city—one of the fastest growing mega cities in the world, is continuously changing due to un-planned urbanization. For example, the wetlands of the city have been shrinking. This study evaluates we... Landscape of Dhaka city—one of the fastest growing mega cities in the world, is continuously changing due to un-planned urbanization. For example, the wetlands of the city have been shrinking. This study evaluates wetland changes in Dhaka Metropolitan Area (DMA), Bangladesh, between 1978 and 2009. Spatial and temporal dynamics of wetland changes were quantified using four Landsat images, a supervised classi?cation algorithm and the post-classi?cation change detection technique in GIS environment. Accuracy of the Landsat-derived wetland maps ranged from 87% to 92.5%. The analysis revealed that area of wetland and Rivers & Khals in Dhaka city decreased significantly over the last 30 years by 76.67% and 18.72% respectively. This changing trend of wetlands makes the drainage system of Dhaka City vulnerable, creating water logging problems and their consequences. Land filling and encroachment were recognized to be the main reasons for shrinking of the wetlands in the city. Development and alteration of the existing water bodies should consider the natural hydrological conditions. 展开更多
关键词 WETLANDS Remote Sensing GIS Dhaka CITY BANGLADESH change analysis
暂未订购
Analysis of vulnerability and resilience to climate change induced shocks in North Shewa, Ethiopia 被引量:5
15
作者 Gutu Tesso Bezabih Emana Mengistu Ketema 《Agricultural Sciences》 2012年第6期871-888,共18页
This article analyzes the vulnerability and resilience levels of farm households in North Shewa, Ethiopia, using a survey of 452 households. Agro ecological based classification was done to analyze vulnerability to cl... This article analyzes the vulnerability and resilience levels of farm households in North Shewa, Ethiopia, using a survey of 452 households. Agro ecological based classification was done to analyze vulnerability to climate change induced shocks. Integrated vulnerability analysis approach was employed to develop indexes for socioeconomic and biophysical indicators. The indicators have been classified into adaptive capacity, exposure and sensitivity to climate change impact. Then Principal Component Analysis was used to compute vulnerability index of each agro ecological zone. The result shows that farmers living in the highland areas were very much vulnerable to natural shocks compared to those living in the lowland area. In order to identify and analyse the determinants of resilience to climate change impacts, ordered probit model was used. Households were classified into three categories based on the time they take to bounce back after natural shocks. The model outputs indicate that farmers with better investment on natural resource management, access to market, better social network, access to credit, preparedness, saving liquid assets, access to irrigation and better level of education exhibited greater level of resilience during and after climate change induced shocks. 展开更多
关键词 Climate change VULNERABILITY RESILIENCE Principal Component analysis ORDERED PROBIT Ethiopia
暂未订购
Analysis of the Climate Features and Changes of Heavy Fog in Wusu City 被引量:3
16
作者 李彦杰 马琳 +1 位作者 闫勇 白学甫 《Meteorological and Environmental Research》 CAS 2010年第8期46-48,共3页
Based on the measured data of heavy fog in Wusu County during 1954-2009,its temporal and spatial distribution characteristics were analyzed.The results showed that heavy fog in Wusu mainly happened from later autumn t... Based on the measured data of heavy fog in Wusu County during 1954-2009,its temporal and spatial distribution characteristics were analyzed.The results showed that heavy fog in Wusu mainly happened from later autumn to beginning of the next spring.The most was in December,the least was in January.It had significant regional features and seasonal distribution characteristics.However,the days of heavy fog was irregular,but it was accordant with the decrease trend of frog days in recent years in China,while it was not significant.The situations of high-altitude uniform pressure field and the surface pressure field had a direct relationship with the formation of heavy fog. 展开更多
关键词 Heavy fog Climate character changes analysis China
在线阅读 下载PDF
Influence of lane change on stability analysis for two-lane traffic flow 被引量:2
17
作者 郑亮 马寿峰 钟石泉 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第8期495-507,共13页
This paper deals mainly with the influence of lane changing behaviours on the stability of two-lane traffic flow under a periodic boundary condition. Following the description of an optimal velocity model for two vehi... This paper deals mainly with the influence of lane changing behaviours on the stability of two-lane traffic flow under a periodic boundary condition. Following the description of an optimal velocity model for two vehicle groups and the derivation of their stability conditions, the feedback signals, which involve information about vehicles from both lanes acting on the two-lane traffic system, are introduced into the optimal velocity model. The control signals play a role in alleviating the traffic jam only if the traffic state is in congestion, and their role will vanish if the traffic state is in the steady state. The numerical simulations show that lane changing behaviours can break the steady state of two-lane traffic flow and aggravate the traffic disturbance, but the control method would successfully suppress the traffic jam eventually, which implies that the conclusions obtained here have certain theoretical and practical significance. 展开更多
关键词 stability analysis optimal velocity model lane changing behaviours feedback signals
原文传递
Research on spatial calculating analysis model of landuse change 被引量:5
18
作者 张新长 潘琼 赵元 《Journal of Geographical Sciences》 SCIE CSCD 2004年第3期359-365,共7页
The spatial calculating analysis model is based on GIS overlay. It will compartmentalize the land in research district into three spatial types: unchanged parts, converted parts and increased parts. By this method we ... The spatial calculating analysis model is based on GIS overlay. It will compartmentalize the land in research district into three spatial types: unchanged parts, converted parts and increased parts. By this method we can evaluate the numerical model and dynamic degree model for calculating land-use change rates. Furthermore, the paper raises the possibility of revising the calculating analysis model of spatial information in order to predicate more precisely the dynamic changing level of all types of land uses. In the most concrete terms, the model is used mainly to understand changed area and changed rates (increasing or decreasing) of different land types from microcosmic angle and establish spatial distribution and spatio-temporal principles of the changing urban lands. And we will try to find out why the situation can take place by combining social and economic situations. The result indicates the calculating analysis model of spatial information can derive more accurate procedure of spatial transference and increase of all kinds of land from microcosmic angle. By this model and technology we can conduct the research of land-use spatio-temporal structure evolution more systematically and more deeply, and can obtain a satisfactory result. The result will benefit the rational planning and management of urban land use of developed coastal areas in China in the future. 展开更多
关键词 land use dynamic change spatial calculating analysis model
在线阅读 下载PDF
Comparison of performance between rescaled range analysis and rescaled variance analysis in detecting abrupt dynamic change 被引量:2
19
作者 何文平 刘群群 +1 位作者 姜允迪 卢莹 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期581-588,共8页
In the present paper, a comparison of the performance between moving cutting data-rescaled range analysis (MC- R/S) and moving cutting data-rescaled variance analysis (MC-V/S) is made. The results clearly indicate... In the present paper, a comparison of the performance between moving cutting data-rescaled range analysis (MC- R/S) and moving cutting data-rescaled variance analysis (MC-V/S) is made. The results clearly indicate that the operating efficiency of the MC-R/S algorithm is higher than that of the MC-V/S algorithm. In our numerical test, the computer time consumed by MC-V/S is approximately 25 times that by MC-R/S for an identical window size in artificial data. Except for the difference in operating efficiency, there are no significant differences in performance between MC-R/S and MC-V/S for the abrupt dynamic change detection. Mc-R/s and MC-V/S both display some degree of anti-noise ability. However, it is important to consider the influences of strong noise on the detection results of MC-R/S and MC-V/S in practical application 展开更多
关键词 moving cutting data-rescaled range analysis moving cutting data-rescaled variance analysis abrupt dynamic change
原文传递
Trend Analysis in Standardized Precipitation Index and Standardized Anomaly Index in the Context of Climate Change in Southern Togo 被引量:7
20
作者 Komlan Koudahe Adewumi J. Kayode +2 位作者 Awokola O. Samson Adekunle A. Adebola Koffi Djaman 《Atmospheric and Climate Sciences》 2017年第4期401-423,共23页
Rainfall and temperature are climatic variables mostly affected by global warming. This study aimed to investigate the temporal trend analysis in annual temperature and rainfall in the Southern Togo for the 1970-2014 ... Rainfall and temperature are climatic variables mostly affected by global warming. This study aimed to investigate the temporal trend analysis in annual temperature and rainfall in the Southern Togo for the 1970-2014 period. Daily and annual rainfall and temperature were collected from four weather stations at Atakpame, Kouma-Konda, Lome, and Tabligbo. The temperature variability was determined by the Standardized Anomaly Index (SAI) and the annual rainfall variability was determined using the Standardized Precipitation Index (SPI). The Mann-Kendall test was used for trend analysis. Mann-Kendall statistical test for the mean annual, mean annual minimum and maximum temperature from 1970 to 2014 showed significant warming trends for all stations except Kouma-Konda where mean annual maximum temperature had exhibited non significant cooling trend (P = 0.01). For Standardized Precipitation Index in the 12-month time scale, dry tendency dominates Atakpamé (55.7%) and Kouma-Konda (55.5%) while wet tendency dominates slightly Lomé (50.9%) and Tabligbo (51.4%). The Mann-Kendall test revealed an increasing trend in standardized anomaly index at all the sites, prejudicial to rainfed agriculture practiced by about 90% of Togolese crop growers. The trend analysis in the climate variables indicated a change in climate that necessitates some specific actions for resources management sustainability and conservation. 展开更多
关键词 TREND analysis MANN-KENDALL Test RAINFALL Temperature Climate change
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部