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Evaluation of COVID-19 Cases and Vaccinations in the State of Georgia, United States: A Spatial Perspective
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作者 Oluwaseun Ibukun Olawale Oluwafemi +3 位作者 Oluwaseun Babatunde Fahmina Binte Ibrahim Yahaya Danjuma Samson Lamela Mela 《Journal of Geographic Information System》 2024年第3期167-182,共16页
This study evaluates the distribution of COVID-19 cases and mass vaccination campaigns from January 2020 to April 2023. There are over 235,000 COVID-19 cases and over 733,000 vaccinations across the 159 counties in th... This study evaluates the distribution of COVID-19 cases and mass vaccination campaigns from January 2020 to April 2023. There are over 235,000 COVID-19 cases and over 733,000 vaccinations across the 159 counties in the state of Georgia. Data on COVID-19 was acquired from usafact.org while the vaccination records were obtained from COVID-19 vaccination tracker. The spatial patterns across the counties were analyzed using spatial statistical techniques which include both global and local spatial autocorrelation. The study further evaluates the effect of vaccination and selected socio-economic predictors on COVID-19 cases across the study area. The result of hotspot analysis reveals that the epicenters of COVID-19 are distributed across Cobb, Fulton, Gwinnett, and DeKalb counties. It was also affirmed that the vaccination records followed the same pattern as COVID-19 cases’ epicenters. The result of the spatial error model performed well and accounted for a considerable percentage of the regression with an adjusted R squared of 0.68, Akaike Information Criterion (AIC) 387.682 and Breusch-Pagan of 9.8091. ESDA was employed to select the main explanatory variables. The selected variables include vaccination, population density, percentage of people that do not have health insurance, black race, Hispanic and these variables accounted for 68% of the number of COVID-19 cases in the state of Georgia during the study period. The study concludes that both COVID-19 cases and vaccinated individuals have spatial peculiarities across counties in Georgia state. Lastly, socio-economic variables and vaccination are very important to reduce the vulnerability of individuals to COVID-19 disease. 展开更多
关键词 COVID-19 VACCINATION Spatial Autocorrelation Georgia Spatial Pattern Spatial Regression
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Research and Experience Reference on China’s Implementation of Low Carbon Strategy
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作者 Renrui Wang 《Journal of Geoscience and Environment Protection》 2024年第6期57-80,共24页
Economic development has brought about global greenhouse gas emissions, which in turn has brought about global climate change. This research paper aims to compare the strengths and weaknesses that China has demonstrat... Economic development has brought about global greenhouse gas emissions, which in turn has brought about global climate change. This research paper aims to compare the strengths and weaknesses that China has demonstrated in the implementation of its low-carbon city strategy and to summarise the valuable experience that China can provide to the world in the implementation of its low-carbon city strategy. This essay analyses in depth the advantages that China has shown in the areas of renewable energy use and government mechanisms, as well as the shortcomings that it has shown in the areas of eco-efficiency industrial structure and capacity upgrading. Then, the paper summarises the successful experiences of the Chinese government in the establishment of renewable energy use and governmental mechanisms, such as the local government’s ability to coordinate multiple sectors (industrial sector, energy sector, etc.) and the implementation of responsibilities. In comparison, the paper also further discusses that China’s implementation of a low-carbon strategy in the future may have more eco-efficiency, industrial structure and capacity upgrading. 展开更多
关键词 Low Carbon LCCP Renewable Energy Government Mechanism ECO-EFFICIENCY Capacity Upgrade
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Research of Future Directions and Considerations for Implementation of the Forest City Strategy
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作者 Renrui Wang 《Journal of Geoscience and Environment Protection》 2024年第5期1-16,共16页
A “Forest City” (FC) is an urban area that has a significant amount of forest cover. It is now a green urban development strategy that is supported by numerous nations. This essay compares the many FC implementation... A “Forest City” (FC) is an urban area that has a significant amount of forest cover. It is now a green urban development strategy that is supported by numerous nations. This essay compares the many FC implementation strategies used in developed and developing countries and explores potential future paths for this tactic. The variations between FC in terms of measurement targets, air purification, street trees, and forestry development are thoroughly compared in this research. This essay goes on to explore FC’s potential in the future regarding policy changes and the environment based on this comparison. Therefore, this essay focuses on the necessity of considering industrial innovation, encouraging biodiversity, lowering greenhouse gas emissions, paying attention to forest restructuring, and being more responsive to the issues provided by urbanization in the future global implementation of FC. 展开更多
关键词 Forest City Policy Adjustment Ecological Environment Measurement Objectives
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Examining the Experiences and Challenges of Haze-Fog Governance in China
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作者 Renrui Wang 《Journal of Geoscience and Environment Protection》 2024年第4期45-58,共14页
With the rapid development of industrialisation and urbanisation, China is facing the challenge of severe HF (Haze-Fog) pollution. This essay compares the advantages and disadvantages of China’s HF management and sum... With the rapid development of industrialisation and urbanisation, China is facing the challenge of severe HF (Haze-Fog) pollution. This essay compares the advantages and disadvantages of China’s HF management and summarizes the important lessons China can teach the rest of the world about applying this tactic. China’s capabilities in the digital economy, National Innovation Demonstration Zones, and urban innovation systems are examined in this article, along with its shortcomings in information mechanisms and pollution sources. This essay also summarizes China’s achievements, particularly regarding local autonomy. The essay goes on to say, however, that China is probably going to be under more pressure to manage HF in the future, both in terms of long-term solutions and the economy. 展开更多
关键词 Haze-Fog Control Digital Economy National Innovation Demonstration Zones Local Autonomy
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Spatiotemporal Evolution Characteristics of Urban Land Surface Temperature Based on Local Climate Zones in Xi’an Metropolitan,China
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作者 ZHANG Liping ZHOU Liang +4 位作者 YUAN Bo HU Fengning ZHANG Qian WEI Wei SUN Dongqi 《Chinese Geographical Science》 SCIE CSCD 2023年第6期1001-1016,共16页
Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperatu... Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019. 展开更多
关键词 urban land surface temperature(LST) local climate zones(LCZs) thermal environment time series urban sustainable development Xi’an metropolitan China
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Aerial Extent Analysis and Environmental Problems Identification of Matasagar and Sukhsagar Wetlands in Bangladesh Using GIS and Remote Sensing Tools 被引量:1
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作者 Md. Zakiur Rahman Md. Shahedur Rashid 《Journal of Geographic Information System》 2016年第6期683-691,共9页
Bangladesh is a land of wetlands. Basically, most of them are freshwater wetlands and have great influence on the primary economic activities such as agriculture and fisheries of the country. Due to its important role... Bangladesh is a land of wetlands. Basically, most of them are freshwater wetlands and have great influence on the primary economic activities such as agriculture and fisheries of the country. Due to its important role in the harmonizing ecosystem, wetlands demand much attention as a significant part of our environment. Matasagar and Sukhsagar are very important historical wetlands of Bangladesh. But those are endangered today due to lack of public awareness of the dangers of their activities to the environment and unbridled profit making activities of the commercial users of the wetlands. Comparisons of maps and Google images from 1933 to present have shown that the forest areas of the wetlands have been progressively destroyed, and these have greatly affected the biodiversity of these areas mentioned. GIS (Geographic Information System) and remote sensing techniques are used to identify the changes in the aerial extent of those wetlands. This study also tried to explore present environmental conditions by in-situ observation. This is high time;some serious steps should be taken to ensure the conservation and preservation of these areas mentioned. 展开更多
关键词 Historical Wetland Extent Analysis Environment Problems GIS Remote Sensing
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Spatio-temporal Pattern and Spatial Heterogeneity of Ecotones Based oh Land Use Types of Southeastern Da Hinggan Mountains in China 被引量:4
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作者 YU Lingxue ZHANG Shuwen +3 位作者 LIU Tingxiang TANG Junmei BU Kun YANG Jiuchun 《Chinese Geographical Science》 SCIE CSCD 2015年第2期184-197,共14页
Ecotones have received great attention due to its critical function in energy flux, species harbor, global carbon sequestration, and land-atmosphere interaction. This study investigated land use pattern and spatial he... Ecotones have received great attention due to its critical function in energy flux, species harbor, global carbon sequestration, and land-atmosphere interaction. This study investigated land use pattern and spatial heterogeneity of the ecotones among agricultural land, forest land, and grassland of the southeastern Da Hinggan Mountains in the northeastern China. The change of these delineated ecotones under different slopes and aridity conditions was analyzed by two landscape indices, edge density(ED) and core area percentage of landscape(CPL), to explore the inter-linkage between spatial structure of ecotones and socioeconomic development and land management. Specifically, the ecotones such as agriculture-forest(AF) ecotone, forest-grassland(FG) ecotone, and agriculture-forestgrassland(AFG) ecotone moved from the arid southeast to the humid northwest. The flat area with small slope is more edge-fragmented than the steep area since the ED decreases as the slope increases. The AF ecotone mostly found in the humid region is moving to more humid areas while the agriculture-grassland(AG) ecotone mostly found in the dry region is moving towards the drier region. 展开更多
关键词 生态交错带 土地利用类型 空间异质性 大兴安岭 东南部 时空格局 中国 农业用地
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Analysis of Change Point in Surface Temperature Time Series Using Cumulative Sum Chart and Bootstrapping for Asansol Weather Observation Station, West Bengal, India 被引量:3
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作者 Ansar Khan Soumendu Chatterjee +1 位作者 Dipak Bisai Nilay Kanti Barman 《American Journal of Climate Change》 2014年第1期83-94,共12页
This paper aims to detect the short-term as well as long-term change point in the surface air temperature time series for Asansol weather observation station, West Bengal, India. Temperature data for the period from 1... This paper aims to detect the short-term as well as long-term change point in the surface air temperature time series for Asansol weather observation station, West Bengal, India. Temperature data for the period from 1941 to 2010 of the said weather observatory have been collected from Indian Meteorological Department, Kolkata. Variations and trends of annual mean temperature, annual mean maximum temperature and annual minimum temperature time series were examined. The cumulative sum charts (CUSUM) and bootstrapping were used for the detection of abrupt changes in the time series data set. Statistically significant abrupt changes and trends have been detected. The major change point in the annual mean temperatures occurred around 1986 (0.57°C) at the period of 25 years in the long-term regional scale. On the other side, the annual mean maximum and annual mean minimum temperatures have distinct change points at level 1. There are abrupt changes in the year 1961 (Confidence interval 1961, 1963) for the annual mean maximum and 1994 (Confidence interval 1993, 1996) for the annual mean minimum temperatures at a confidence level of 100% and 98%, respectively. Before the change, the annual mean maximum and annual mean minimum temperatures were 30.90°C and 23.99°C, respectively, while after the change, the temperatures became 33.93°C and 24.84°C, respectively. Over the entire period of consideration (1941-2010), 11 forward and backward changes were found in total. Out of 11, there are 3 changes (1961, 1986 and 2001) in annual mean temperatures, 4 changes (1957, 1961, 1980 and 1994) in annual mean maximum temperatures, and rest 4 changes (1968, 1981, 1994 and 2001) are associated with annual mean minimum temperature data set. 展开更多
关键词 BOOTSTRAPPING CHANGE POINT CUSUM Temperature Time SERIES
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Remote Sensing and GIS for the Spatio-Temporal Change Analysis of the East and the West River Bank Erosion and Accretion of Jamuna River (1995-2015), Bangladesh 被引量:1
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作者 Md Arafat Hassan Suriya Jesmine Ratna +1 位作者 Masud Hassan Sonia Tamanna 《Journal of Geoscience and Environment Protection》 2017年第9期79-92,共14页
Jamuna River is one of the principal rivers of Bangladesh, changing continuously due to erosion and accretion over the past decades. This analysis evaluates the East Bank and the West Bank erosion and accretion betwee... Jamuna River is one of the principal rivers of Bangladesh, changing continuously due to erosion and accretion over the past decades. This analysis evaluates the East Bank and the West Bank erosion and accretion between 1996 and 2015 for Jamuna River. An unsupervised classification algorithm and post-classification change employing skills in Geographic Information System are performed to evaluate spatial and temporal dynamics of erosion and accretion for different points of Jamuna River using Bangladesh. Landsat image (1995, 2005, 2015). The correctness of the Landsat-produced map ranges from 82% to 84%. It has been evidently observed that changes in the proportion of erosion and accretion differ in different points of Jamuna River. The highest eroded area is 3.82 square kilometers (km2) during the period of 1995 to 2005 and the highest accreted area is 6.15 square kilometers (km2) during the period of 1995 to 2015. The erosion and accretion values fluctuated from place to place. The changing trend of Riverbank is creating many socio-economic problems in the proximate areas. 展开更多
关键词 REMOTE Sensing GIS RIVER EROSION ACCRETION CHANGE Analysis Jamuna RIVER
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Variability of Sea Ice from 2008 to 2019 in the Bohai and Northern Huanghai Sea, China and the Relationship with Climatic Factors
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作者 GONG Shaoqi CHEN Wenqian +2 位作者 ZHANG Cunjie YAN Qingyun YANG Hong 《Journal of Ocean University of China》 SCIE CAS CSCD 2022年第5期1189-1197,共9页
Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still l... Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices. 展开更多
关键词 sea ice polar-orbit meteorological series satellites FY-3/VIRR Bohai Sea climatic factors
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Perceptions and Barriers to Contraceptive Use among Adolescents Aged 15 - 19 Years in Kenya: A Case Study of Nairobi
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作者 Joyce Kinaro Murungaru Kimani +1 位作者 Lawrence Ikamari Elias H. O. Ayiemba 《Health》 2015年第1期85-97,共13页
Even after the launch of family planning program in Kenya, in 1967, contraceptive use among adolescents has remained below 10 percent while child bearing has increased from 2 percent at age 15 to 36 percent at age 19.... Even after the launch of family planning program in Kenya, in 1967, contraceptive use among adolescents has remained below 10 percent while child bearing has increased from 2 percent at age 15 to 36 percent at age 19. To understand the roles of perceptions and barriers on contraceptive use, a mixed method study design was applied to a conceptual framework that operationalized these concepts using data from different sources of social interactions in Nairobi, Kenya. Quantitative data were collected from 1119 adolescents aged 15 - 19 years. Qualitative data were collected from adolescents, adolescents’ parents and their school teachers. The later were analyzed and interpreted together with the results from cross-tabulations and logistic regression in order to understand the roles of perceptions and barriers. Contraceptive use was found to be 8.6 percent among the adolescents. Overall, unfavourable perceptions among adolescents, parents and teachers seemed to have contributed to low contraceptive use. Unfavourable perceptions played greater role compared to barriers such as sexual partner communication, opinion on adolescents to use a contraceptives and ability to seek contraceptives. Qualitative data show that teachers and parents lack adequate information and skills to discuss sexuality issues. Linking data among adolescents, parents and teachers help to understand the roles of perceptions and barriers to contraceptive use in Kenya. The findings suggest capacity building of teachers and parents on accurate sexuality information for adolescents while services should be youth-friendly. 展开更多
关键词 CONTRACEPTIVE Use PERCEPTIONS and Barriers SEXUALITY Information
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The Spatial Variability and Temporal Dynamics of Soil Properties as Affected by Visitors’ Pressure in an Urban Park
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作者 Helena M. Zhevelev Pariente Sarah Atar Oz 《Journal of Environmental Protection》 2013年第8期52-64,共13页
Soil properties and their tempo-spatial heterogeneity, affected by visitors’ pressure, season and soil depth, were studied in an urban park in Tel-Aviv. Soil was sampled twice yearly in wet and dry seasons. In each s... Soil properties and their tempo-spatial heterogeneity, affected by visitors’ pressure, season and soil depth, were studied in an urban park in Tel-Aviv. Soil was sampled twice yearly in wet and dry seasons. In each season soil was sampled from areas exposed to differing levels of visitors’ pressure (VP), and designated “no VP (Control)”, “High VP” and “Low VP”. The soil samples were taken from two depths. For each soil sample, moisture, organic matter and soluble-ion contents, pH, and electrical conductivity were determined. It was found that different properties were differently affected by VP, seasonal dynamics and soil depth: organic matter content, penetration depth and sodium concentration were the most sensitive to VP;Soil moisture did not respond to VP, but sharply reflected seasonal changes;Calcium and organic matter contents were significantly affected by the soil depth. The sensitivity of soil properties to VP increased from March to July, and the upper soil layer was more sensitive to seasonal dynamics and VP than the deeper layer. Some soil properties exhibited “spotty” patterns;others a “frontal” one. Organic matter content was completely controlled by VP at both depths and in both seasons, and could be used as an indicator of soil status in recreation areas. Visitors’ activities included trampling and other anthropogenic factors that enhanced the spatial changes and seasonal dynamics of soil properties. Based on these measurements the intensity of soil degradation and dynamics was evaluated and used to describe the soil status in an urban park. 展开更多
关键词 URBAN PARK URBAN SOIL Visitors’ PRESSURE SOIL Spatial Variability Seasonal Dynamics
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Impact of Climate Change on Species Distribution and Carbon Storage of Agroforestry Trees on Isolated East African Mountains
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作者 Dickens Odeny Faith Karanja +2 位作者 Geoffrey Mwachala Petri Pellikka Rob Marchant 《American Journal of Climate Change》 2019年第3期364-386,共23页
Changes in climate will affect conditions for species growth and distribution, particularly along elevation gradients, where environmental conditions change abruptly. Agroforestry tree (AGT) species on the densely inh... Changes in climate will affect conditions for species growth and distribution, particularly along elevation gradients, where environmental conditions change abruptly. Agroforestry tree (AGT) species on the densely inhabited slopes of Mount Kilimanjaro and Taita Hills will change their elevation distribution, and associated carbon storage. This study assesses the potential impacts of climate change by modelling species distribution using maximum entropy. We focus on important agroforestry tree species (Albiziagummifera, Mangiferaindica and Perseaamericana) and projected climate variables under IPCC-AR5 RCP 4.5 and 8.5 for the mid-century (2055) and late century (2085). Results show differential response: downward migration for M. indica on the slopes of Mount Kilimanjaro is contrasted with Avocado that will shift upslope on the Taita Hills under RCP 8.5. Perseaamericana will lose suitable habitat on Kilimanjaro whereas M. indica will expand habitat suitability. Potential increase in suitable areas for agroforestry species in Taita Hills will occur except for Albizia and Mango which will potentially decrease in suitable areas under RCP 4.5 for period 2055. Shift in minimum elevation range will affect species suitable areas ultimately influencing AGC on the slopes of Mount Kilimanjaro and Taita Hills. The AGC for agroforestry species will decrease on the slopes of Mount Kilimanjaro but AGC for Mango will increase under RCP 8.5 for period 2055 and 2085. In Taita Hills, AGC will remain relatively stable for A. gummifera and P. americana under RCP 8.5 for period 2055 and 2085 but decrease in AGC will occur for M. indica under projected climate change. Climate change will affect AGT species and the amount of carbon stored differently between the sites. Such insight can inform AGT species choice, and conservation and support development by improving carbon sequestration on sites and reliable food production. 展开更多
关键词 AGROFORESTRY Carbon Storage CLIMATE Change Albizia AVOCADO MANGO
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Detecting and assessing Spartina invasion in coastal region of China: A case study in the Xiangshan Bay
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作者 ZHU Changming ZHANG Xin QI Jiaguo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第4期35-43,共9页
Spartina alterniflora is one of exotic plants along the coastal region in China. It was introduced as an important engineering approach to ecological restoration in the later 1970 s. However, owing to its good adaptab... Spartina alterniflora is one of exotic plants along the coastal region in China. It was introduced as an important engineering approach to ecological restoration in the later 1970 s. However, owing to its good adaptability and strong reproductive capacity, the introduced species is explosively spreading along the coastal region quickly and resulting in a significant impact on the health and safety of coastal wetland ecosystems. It is imperative to quantify the spatial extent and the rate of S. alterniflora sprawl in order to assess its ecological damages and economic impacts. Remote sensing techniques have been used to address these challenges but large unsuccessful due to mixed spectral properties. In this study, a hybrid method was proposed for S. alterniflora detection using medium resolution remote sensing images by integrating both spatial and spectral features of S. alterniflora. The hybrid method consists of two phases:(1) delineation of intertidal zone as the potential area of S. alterniflora distribution and(2) extraction of S. alterniflora fraction distribution with a mixture pixel analysis. The proposed method was tested at the Xiangshan Bay on the east coastal region of Zhejiang Province, China, and mapped the spatial extent of S. alterniflora with Landsat datasets in the 2003, 2009 and 2014. The results showed that, the S. alterniflora has grown exponentially over past 10 years. In 2003, the total area of S. alterniflora was about 590 hm2, but quickly reached to 1 745 hm2 in 2009, and 5 715 hm2 in 2014. With a rate of approximately 10-folds growth within a decade, the invasive species almost occupied all muddy beaches to become the most dominant coastal salt vegetation in this region. It is believed that the strong biological reproductive capacity was the primary reason for such quick spread and at the same time human reclamation activities were also believed to have facilitated the environmental conditions for S. alterniflora sprawl. 展开更多
关键词 Spartina alterniflora invasive species remote sensing Xiangshan Bay
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Ecogeomorphic Feedbacks in Semiarid Rangelands:A Review 被引量:5
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作者 I.STAVI H.LAVEE +1 位作者 E.D.UNGAR P.SARAH 《Pedosphere》 SCIE CAS CSCD 2009年第2期217-229,共13页
The ecogeomorphic processes occurring on semiarid rangelands are reviewed,with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas,and the way live... The ecogeomorphic processes occurring on semiarid rangelands are reviewed,with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas,and the way livestock presence affected these interactions.Compared with intershrub areas,the shrub patches had a higher soil porosity,infiltration capacity,water-holding capacity,hydraulic conductivity,structural stability,and organic matter content,and lower bulk density.These di?erences derived from a host of processes whose intensity was less in the shrub patches,including raindrop impact,mechanical crust formation,overland water flow,soil erosion,evaporative moisture loss,and flock trampling. There was also greater shading of the soil surface;soil and litter deposition;water accumulation;microbial,fungal,and mesofaunal activities in the shrub patches.The overland flow of water carried soil and litter from the intershrub areas to the shrub patches and resulted in microtopographic modifications that tended to strengthen these source-sink relations. Grazing had an impact on these processes,not only at the shrub-intershrub scale but also within the intershrub areas, through the creation of highly compacted trampling routes.The combined role of the above ecogeomorphic processes was to maintain the rangeland’s functionality.Without these inter-relationships,water loss,soil erosion,and nutrient depletion would occur at the hillside scale,causing degradation of the landscape. 展开更多
关键词 半干旱 牧场 反馈 土壤孔隙度 水力传导系数 源库关系 土壤侵蚀 有机质含量
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Geochemical contamination in the mine affected soil of Raniganj Coalfield——A river basin scale assessment 被引量:2
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作者 Abhijit Manna Ramkrishna Maiti 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第5期1577-1590,共14页
The study aimed to assess the heavy metals(K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Sr, Zr) contamination in the soil of mine affected Singaran river basin and to analyse spatial variation in the contamination level... The study aimed to assess the heavy metals(K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Sr, Zr) contamination in the soil of mine affected Singaran river basin and to analyse spatial variation in the contamination level considering 32 soil samples. Elemental analysis of soil samples has been performed through Energy Dispersive X-ray Analysis(EDX) to quantify the elemental concentration(mg kgà1). Heavy metal concentrations have been assessed through geo-accumulation index(Igeo) and enrichment factor(EF).Indices showed soils have moderate accumulation of most of the metals with moderate enrichment of Sr,Zr, Zn, Cu and Ni. Soil contamination level assessment has been carried out using indices like Contamination Factor(CF), degree of contamination(C_(deg)), modified degree of contamination(m C_(deg)) and Pollution Load Index(PLI). CF shows moderate to considerable contamination by Sr, Zr, Ca, Cu, Mn, Zn and Ni. Mean indices values(m C_(deg)and PLI for the entire basin are 3.38 and 2.23 respectively) show low to moderate level of soil contamination. These indices result have been mapped and analysed in GIS platform to get spatial variation of pollution level. Opencast mines dominate middle catchment area and so is comparatively contaminated. Sample sites 11, 18 and 25 evidenced high values of all indices of pollution load. From the ecological standpoint Ecological Risk Factor(Er) and Potential Ecological Risk Index(RI) have been estimated to assess regional threat to native soil environment and it shows low ecological risk potential. Analysis shows that mine dominated soil of the entire Singaran basin is less contaminated in all respect but tends to the moderate contamination level at the mid-catchment area,especially by Sr, Zr, Zn, Cu and Ni. 展开更多
关键词 HEAVY metals SOIL contamination POLLUTION indices POLLUTION load ECOLOGICAL risk Singaran basin
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Trend Analysis of Rainfall in Ganga Basin, India during 1901-2000 被引量:3
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作者 Suman Bera 《American Journal of Climate Change》 2017年第1期116-131,共16页
Shortage of water in the river in relation to rainfall change plays a pivotal role in water sharing like Ganga. In attempt to understand the rainfall changes, Mann-Kendall test and Sen’s slope estimation on hundred y... Shortage of water in the river in relation to rainfall change plays a pivotal role in water sharing like Ganga. In attempt to understand the rainfall changes, Mann-Kendall test and Sen’s slope estimation on hundred years’ (1901-2000) rainfall data of 236 districts in entire Ganga basin were run. Half of the districts showed a decreasing trend in annual rainfall in which 39 districts were statistically significant. During pre-monsoon (Jan.-May), 78% of the total districts showed the decreasing trend with the significance of 54 districts. A majority of the districts under the Kosi, Gandak and Sone sub-basins showed the significant negative trend in annual, pre-monsoon and post-monsoon season. So, there need some districts’ and sub-basins’ wise strategies to cope with the situation in the context of climate change. 展开更多
关键词 MANN-KENDALL Test Sen’s SLOPE ESTIMATOR CLIMATE Change
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Detection of Approximate Potential Trend Turning Points in Temperature Time Series (1941-2010) for Asansol Weather Observation Station, West Bengal, India 被引量:3
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作者 Soumendu Chatterjee Dipak Bisai Ansar Khan 《Atmospheric and Climate Sciences》 2014年第1期64-69,共6页
Researches are being carried out world-wide to understand the nature of temperature change during recent past at different geographical scales so that comprehensive inferences can be drawn about recent temperature tre... Researches are being carried out world-wide to understand the nature of temperature change during recent past at different geographical scales so that comprehensive inferences can be drawn about recent temperature trend and future climate. Detection of turning points in time series of meteorological parameters puts challenges to the researches. In this work, the temperature time series from 1941 to 2010 for Asansol observatory, West Bengal, India, has been considered to understand the nature, trends and change points in the data set using sequential version of Mann-Kendall test statistic. Literatures suggest that use of this test statistic is the most appropriate for detecting climatic abrupt changes as compared to other statistical tests in use. This method has been employed upon monthly average temperatures recorded over the said 70 years for detection of abrupt changes in the average temperature of each of the months. The approximate potential trend turning points have been calculated separately for each month (January to December). Sequential version of Mann-Kendall test statistic values for the months of July and August is significant at 95% confidence level (p 0.05). The average temperature for most of the other months has shown an increasing trend but more significant rise in July and August temperature has been recognized since 1960s. 展开更多
关键词 Sequential Version of MANN-KENDALL Test Statistic TEMPERATURE Trends TURNING Points
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Using Time Series of Satellite Images to Detect Vegetation Cover Change in Dhaka City 被引量:1
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作者 Sami Al Jaber Amit Kumar Ghosh Mallik Sezan Mahmud 《Journal of Geographic Information System》 2014年第6期653-663,共11页
The spatial land cover pattern of Dhaka city is restlessly altering as it has highest growing rates among megacities. Due to high urbanization rates, land use is changing from natural to man-made along with resource e... The spatial land cover pattern of Dhaka city is restlessly altering as it has highest growing rates among megacities. Due to high urbanization rates, land use is changing from natural to man-made along with resource extractions that accelerate the land cover changes. This study has evidently given the glimpse of the raising concern by assessing the loss of vegetation coverage of Dhaka Metropolitan Area using multi-temporal Landsat imageries. 20 years satellite data have been used to detect the vegetation cover changes in Dhaka city with an interval of 10 years. Study reveals that 66.87 square kilometer vegetation coverage of Dhaka Metropolitan Area is lost during the whole time period. The rate of loss of vegetation coverage is very severe in Dhanmondi, Gulshan, Uttara, Demra, Mirpur, Sabujbagh, Ramna, Mohammadpur, Kafrul, Shyampur and so on. The overall precision of my Landsat-derived vegetation coverage maps is 92.5%. 展开更多
关键词 Dhaka METROPOLITAN Area VEGETATION COVERAGE LANDSAT Imageries
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Trends of Shoreline Position: An Approach to Future Prediction for Balasore Shoreline, Odisha, India
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作者 Nilay Kanti Barman Soumendu Chatterjee Ansar Khan 《Open Journal of Marine Science》 2015年第1期13-25,共13页
The present study aims to analyze the shift in shoreline due to coastal processes and formulate available for best estimate of future shoreline positions based on precedent shorelines. Information on rates and trends ... The present study aims to analyze the shift in shoreline due to coastal processes and formulate available for best estimate of future shoreline positions based on precedent shorelines. Information on rates and trends of shoreline change can be used to improve the understanding of the underlying causes and potential effects of coastal erosion which can support informed coastal management decisions. In this paper, researchers go over the changes in the recent positions of the shoreline of the Balasore coast for the 38 years from 1975 through 2013. The study area includes the Balasore coastal region from Rasalpur to Udaypur together with Chandipur, Choumukh, Chandrabali as well as Bichitrapur. Transects wise shoreline data base were developed for approximately 67 kilometers of shoreline and erosional/accretional scenario has also been analysed by delineating the shoreline from Landsat imageries of 1975, 1980, 1990, 1995, 2000, 2005, 2010 and 2013. A simple Linear Regression Model and End Point Rate (EPR) have been adopted to take out the rate of change of shoreline and its future positions, based on empirical observations at 67 transects along the Balasore coast. It is found that the north eastern part of Balasore coast in the vicinity of Subarnarekha estuary and Chandrabali beach undergo high rates of shore line shift. The shoreline data were integrated for long- (about 17 years) and short-term (about 7 years) shift rates analysis to comprehend the shoreline change and prediction. For the prediction of future shoreline, the model has been validated with the present shoreline position (2013). The rate of shoreline movement calculated from the fixed base line to shoreline position of 1975, 1980, 1990, 1995, 2000, 2005 and 2010 and based on this, the estimated shoreline of 2013 was calculated. The estimated shoreline was compared with the actual shoreline delineated from satellite imagery of 2013. The model error or positional shift at each sample point is observed. The positional error varies from??4.82 m to 212.41 m. It has been found that model prediction error is higher in the left hand side of river Subarnarekha. The overall error for the entire predicted shoreline was found to be 41.88 m by Root Mean Square Error (RMSE). In addition, it was tested by means difference between actual and predicted shoreline positions using “t” test and it has been found that predicted shore line is not significantly different from actual shoreline position at (t132 = 0.278) p < 0.01. 展开更多
关键词 Linear Regression Model End Point Rate ROOT Mean SQUARE Error SHORELINE Change SHORELINE PREDICTION
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