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Application of ensemble kalman filter to geophysical parameters retrieval in remote sensing:A case study of kernel-driven BRDF model inversion

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Science China Earth Sciences 2006年第6期49卷 632-640页

作者： QIN Jun1, YAN Guangjian1, LIU Shaomin1, LIANG Shunlin2, ZHANG Hao1, WANG Jindi1 & LI Xiaowen1 1. State Key Laboratory of Remote Sensing Science, School of Geography and Remote Sensing, Research Center for RS&gis, Beijing Normal University, Beijing 100875, China 2. department of Geography, 2181 Lefrak Hall, University of Maryland, College Park, MD20742, USA State Key Laboratory of Remote Sensing Science School of Geography and Remote Sensing Research Center for RS&GIS Beijing Normal University Beijing China department of Geography 2181 Lefrak Hall University of Maryland College Park USA

The use of a priori knowledge in remote sensing inversion has great implications for ensuring the stability of inversion process and reducing uncertainties in retrieved results, especially under the condition of insufficient observations. Common optimization algorithms have difficulties in providing posterior distribution and thus cannot directly acquire uncertainties in inversion results, which is of no benefit to remote sensing application. In this article, ensemble Kalman filter (EnKF) has been introduced to retrieve surface geophysical parameters from remote sensing observations, which has the capability of not merely obtaining inversion results but also giving its posterior distribution. To show the advantage of EnKF, it is compared to standard MODIS AMBRALS algorithm and highly effi-cient global optimization method SCE-UA. The inversion abilities of kernel-driven BRDF models with different kernel combinations at several main cover types are emphatically discussed when observa-tions are deficient and a priori knowledge is introduced into inversion.

关键词： remote sensing inversion, a priori knowledge, posterior distribution, ensemble kalman filter, BRDF, kernel-driven model, albedo.

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A gis-Based Decision Support System for Reducing Air Ambulance Response Times: A Case Study on Public Schools in Jeddah City

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Journal of Geographic Information System 2015年第4期7卷 384-391页

作者： Randa Alharbi department of Geography and gis King Abdulaziz University Jeddah Saudi Arabia

In injuries reducing ambulance response time (time from injury to hospital arrival) is an important factor for saving people’s lives. Helicopter emergency medical services can reduce out-of-hospital transport times because of their high speed and their ability to travel in straight paths?unlike ground ambulance which are restricted to road network paths, as well as the ability toaccess rural or remote area injuries that are difficult to reach by ground ambulance. gis technology aids air ambulance movement planning to reduce out-of-hospital response time based on mathematical and geographic models to support decision making which is necessary from out-of-hospital care providers. The goal of this study is to use gis to develop an efficient DSS to outline where air ambulance can reduce response times, by using spatial analysis tools to create Euclidean distance and direction zones around receiving hospitals. The study concludes that gis technology can be used to develop an efficient DSS to outline where air ambulance can reduce response times, by creating surfaces of Euclidean allocation, direction, and distance that can be used to improve initial response times for the civil defense air rescue and air ambulance services.

关键词： gis DSS Air Ambulance Response Time Jeddah

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Spatial Modeling of Residential Crowding in Alexandria Governorate, Egypt: A Geographically Weighted Regression (GWR) Technique

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Journal of Geographic Information System 2015年第4期7卷 369-383页

作者： Shawky Mansour department of Geography and gis Faculty of Arts Alexandria University Alexandria Egypt

Despite growing research for residential crowding effects on housing market and public health perspectives, relatively little attention has been paid to explore and model spatial patterns of residential crowding over space. This paper focuses upon analyzing the spatial relationships between residential crowding and socio-demographic variables in Alexandria neighborhoods, Egypt. Global and local geo-statistical techniques were employed within gis-based platform to identify spatial?variations of residential crowding determinates. The global ordinary least squares (OLS) model?assumes homogeneity of relationships between response variable and explanatory variables?across the study area. Consequently, it fails to account for heterogeneity of spatial relationships. Local model known as a geographically weighted regression (GWR) was also employed using the same?response variable and explanatory variables to capture spatial non-stationary of residential?crowding. A comparison of the outputs of both models indicated that OLS explained 74 percent of?residential crowding variations while GWR model explained 79 percent. The GWR improvedstrength of the model and provided a better goodness of fit than OLS. In addition, the findings of this analysis revealed that residential crowding was significantly associated with different structural measures particularly social characteristics of household such as higher education and illiteracy. Similarly, population size of neighborhood and number of dwelling rooms were found to have direct impacts on residential crowding rate. The spatial relationship of these measures distinctly varies over the study area.

关键词： Spatial Modelling OLS GWR Residential Crowding Alexandria Neighborhoods

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Spatial risk assessment of opium poppy cultivation in Afghanistan: integrating environmental and socio-economic drivers

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International Journal of Digital Earth 2017年第7期10卷 719-736页

作者： Stefan Kienberger Raphael Spiekermann Dirk Tiede Irmgard Zeiler Coen Bussink department of Geoinformatics–Z_gis University of SalzburgSalzburgAustria Landcare Research Manawatu Mail CentrePalmerston NorthNew Zealand Research and Trend Analysis Branch United Nations Office on Drugs and Crime(UNODC)ViennaAustria

Recently the cultivation of opium poppy in Afghanistan reached unprecedented *** is agreed that the complex and coupled interactions of social,economic and environmental drivers are crucial for understanding the spatial and temporal dynamics of opium poppy cultivation in *** this context,we present an integrated risk concept,which considers environmental and socio-economic drivers of opium poppy cultivation.A set of spatially explicit indicators for the environmental suitability and socio-economic vulnerability was established and populated from a variety of ***,novel methods of modelling homogeneous and spatially explicit regions of opium poppy cultivation suitability,socio-economic vulnerability and risk are developed and *** risk assessment results demonstrate the complex nature of the illicit crops production in Afghanistan and prompt a more profound examination of the drivers of opium poppy cultivation in a spatial *** study also confirms what has already been widely discussed in literature:that reasons for cultivation are spatially diverse and often distinct,meaning that any formulation of generalized explanations cannot be drawn without ignoring a more complex ***,an integrative spatial view of risk,which integrates the social dimension as well as environmental parameters,is required to better identify context-specific intervention measures.

关键词： Opium poppy risk social and environmental determinants integrated modelling policy support regionalization integrated geons

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Assessment of soil quality indicators under different agricultural land uses and topographic aspects in Central Vietnam

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International Soil and Water Conservation Research 2018年第4期6卷 280-288页

作者： Tung Gia Pham Hung Trong Nguyen Martin Kappas Cartography GIS and Remote Sensing DepartmentGottingen UniversityGeorge August University of GoettingenGoldschmidstr.537077 GoettingenGermany University of Agriculture and Forestry Hue UniversityVietnam Ministry of Natural Resources and Environment Vietnam

Soil quality assessment is valuable for agricultural production. In this research, 155 soil samples at two soil depths were collected from four land use types in an agricultural area of the A Luoi district in the Central Vietnam. Differences of soil organic carbon, total nitrogen in soil and soil pH under different land use types and topographic aspects were compared. Soil organic carbon contents in arable land and plantation forest are higher than those in natural forest and grassland (p < 0.05). Conversely, the total nitrogen in natural forest was significantly lesser in comparison to other land use types. Meanwhile there were no significant differences of the total nitrogen content (p < 0.05) among arable land, plantation forest, and grassland. The soil of grassland, natural and plantation forests land use types were more significantly acidic than those of the soils of the arable land use type. Soil organic carbon and total nitrogen showed a decreasing trend while soil depth increased in all land use types. The soil pH in plantation forest and arable land use types showed no significant change in relation to soil depth. Significant differences were not found in topographic aspects and soil organic carbon content;however, the different changing trends of soil organic carbon content between land use types and aspects were found. The impact of slope, elevation, farming system or soil texture accounted for the differences in these soil indicators under different land use types in the A Luoi district.

关键词： Central Vietnam Land use type Hilly area Soil quality Topographic aspects

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Country-scale spatio-temporal monitoring of soil erosion in Iran using the G2 model

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International Journal of Digital Earth 2021年第8期14卷 1019-1039页

作者： Shahin Mohammadi Fatemeh Balouei Khadijeh Haji Abdulvahed Khaledi Darvishan Christos G.Karydas department of Remote Sensing and gis Faculty of Earth SciencesShahid Chamran University of AhvazAhvazIran department of Range and Watershed Management Faculty of Natural ResourcesIsfahan University of TechnologyIsfahanIran department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares UniversityNoorIran dRemote Sensing Engineer EpanomiGreece

The aim of this study was the spatial and temporal monitoring of soil erosion patterns in *** G2 model was used,as an appropriate tool to provide the required month-time step country-wide soil loss maps and statistical *** input parameters were derived with field surveys and remote sensing imagery(MODIS,SRTM,SPOT,and Sentinel-2 scenes).An innovation for G2 was the consideration of the snow cover effect on the rainfall *** was also the first time G2 was used to map such a big country like Iran on a country *** mean annual soil erosion in Iran was found to be 16.5 t ha−1,which is equal to about 2.7 billion tons of soil *** spatial terms,the highest soil loss values were found in the north,west and southwest part of Iran,in the steep slopes in Alborz and Zagros *** temporal terms,the highest and lowest monthly erosion values of 3.2 and 0.09 t ha−1 correspond to January and July,respectively.

关键词： Digital earth Land degradation Sediment yield Sentinel-2 Snow cover effect

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COVID-19 and Ecosyndemic Vulnerability: Implications for El Niño-Sensitive Countries in Latin America

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International Journal of Disaster Risk Science 2021年第1期12卷 147-156页

作者： Ivan J.Ramírez Jieun Lee department of Health and Behavioral Sciences University of Colorado DenverDenverCO 80217USA Consortium for Capacity Building Institute of Arctic and Alpine Research(INSTAAR)University of Colorado BoulderBoulderCO 80308USA department of Geography GISand SustainabilityUniversity of Northern ColoradoGreeleyCO 80639USA

Latin America has emerged as an epicenter of the COVID-19 ***,Peru,and Ecuador report some of the highest COVID-19 rates of incidence and deaths in the *** countries also face synergistic threats from multiple infectious diseases(that is,ecosyndemic)and quasi-periodic El Niño-related hazards every few *** example,Peru,which is highly sensitive to El Niño,already copes with an ecosyndemic health burden that heightens during and following weather and climate extreme *** an ecosyndemic lens,which draws on a multi-disease hazard context of place,this commentary highlights the importance of El Niño as a major factor that not only may aggravate COVID-19 incidence in the future,but also the broader health problem of ecosyndemic vulnerability in Latin America.

关键词： Coronavirus COVID-19 Ecosyndemic El Niño El Niño-Southern oscillation Infectious disease vulnerability Latin America

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Near real-time characterisation of urban environments: a holistic approach for monitoring dengue fever risk areas

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International Journal of Digital Earth 2014年第11期7卷 916-934页

作者： Muhammad Shahzad Sarfraz Nitin Kumar Tripathi Asanobu Kitamoto department of Computer Science COMSATS Institute of Information Technology(CIIT)AbbottabadPakistan Remote Sensing and gis Asian Institute of Technology(AIT)BangkokThailand Digital Content and Media Sciences Research Division National Institute of Informatics(NII)TokyoJapan

Despite frequent use of digital devices in everyday life,cost-effective measurement of public health issues in urban areas is still *** study was,therefore,planned to extract land-use types using object-based and spatial metric approaches to explore the dengue incidence in relation to the surrounding environment in near real-time using Google and Advanced Land Observation Satellite *** characterised image showed useful classification of an urban areawith 77%accuracy and 0.68 *** analysis on public health data indicated that most of the dengue cases were found in densely populated areas surrounded by dense *** living in independent houses having sparsely vegetated surroundings were found to be less *** incidence was more prevalent in people of 5-24 years of age(67%);while in terms of occupation,mostly students,the unemployed,labourers and farmers(88%)were *** general,males were affected slightly more(10%)than *** analyses indicated that most of the dengue cases were around institutions(40%),religious places(18%)and markets(15%).Thus,usage of Digital Earth scalable tools for monitoring health issues would open new ways for maintaining a healthy and sustainable society in the years ahead.

关键词： dengue fever land-use land-cover monitoring dengue risk urban environment object-based classification

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Urogenital schistosomiasis and associated determinant factors among senior high school students in the Dutsin-Ma and Safana Local Government Areas of Katsina State, Nigeria

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Infectious Diseases of Poverty 2016年第1期5卷 609-621页

作者： Tolulope Ebenezer Atalabi Umar Lawal Francis Omowonuola Akinluyi department of Biological Sciences Faculty of ScienceFederal UniversityDutsin-MaP.M.B.5001Dutsin-MaKatsina StateNigeria department of Remote Sensing and gis School of Earth and Mineral SciencesFederal University of TechnologyAkureOndo StateNigeria

Background:Human schistosomiasis is a chronic parasitic disease of poverty caused by the cercariae of digenetic trematodes of the genus *** disease is a major source of morbidity and mortality in 77 low-and middle-income countries in the tropics where 700 million people are at *** a bid to provide relevant epidemiological information to boost control of urogenital schistosomiasis at the state level in Nigeria,we conducted this study with the aim of investigating the disease’s prevalence and intensity,and the determinant factors responsible for its ***:Data on risk factors were obtained from a total of 645 students aged 12─25 years using well-designed *** were collected between 09:45 and 14:00 in universal ***10μl centrifuged sample was examined for the eggs of *** using Motic®(Binocular)Light Microscope(model S-10-P)with a x10 *** infection intensity was recorded as number of eggs per 10 ml of urine *** data were entered into Microsoft Excel 2010 and analyzed using Epi Info™*** among variables were determined using the chi square test and bivariate and multivariate logistic ***:Prevalence of urogenital schistosomiasis was 30.54%among the study population,with a mean infection intensity of 30.27 eggs/10 ml of *** and average intensity were higher in males(28.37%and 32.21 eggs/10 ml of urine respectively)than in females(2.17%and 5 eggs/10 ml of urine respectively).Water contact activities(χ^(2)=29.031,P=0.0000),sex(male)[χ^(2)=109.82;P<0.0001],location(Dutsin─Ma)[χ^(2)=7.19;P=0.0073],age group 18-20(χ^(2)=4.819,P=0.0281),altitude(531─560 m)[χ^(2)=6.84,p=0.0089],fathers doing other brown─collar jobs(χ^(2)=8.449,P=0.0037)and mothers’occupation(χ^(2)=9.470,P=0.0021)were found to be significantly associated with urogenital *** were six times more likely to be infected with the cercariae of *** compared to girls[AOR

关键词： Prevalence Intensity Urogenital schistosomiasis Risk─factors Katsina State Nigeria

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Dynamic Spatio-Temporal Tweet Mining for Event Detection:A Case Study of Hurricane Florence

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International Journal of Disaster Risk Science 2020年第3期11卷 378-393页

作者： Mahdi Farnaghi Zeinab Ghaemi Ali Mansourian gis Center Department of Physical Geography and Ecosystem ScienceLund University22362 LundSweden Faculty of Geodesy and Geomatics K.N.Toosi University of TechnologyTehranIran Center for Middle Eastern Studies Lund University22100 LundSweden

Extracting information about emerging events in large study areas through spatiotemporal and textual analysis of geotagged tweets provides the possibility of monitoring the current state of a *** study proposes dynamic spatio-temporal tweet mining as a method for dynamic event extraction from geotagged tweets in large study *** introduces the use of a modified version of ordering points to identify the clustering structure to address the intrinsic heterogeneity of Twitter *** precisely calculate the textual similarity,three state-of-theart text embedding methods of Word2vec,GloVe,and Fast Text were used to capture both syntactic and semantic *** impact of selected embedding algorithms on the quality of the outputs was *** combinations of spatial and temporal distances with the textual similarity measure were investigated to improve the event detection *** proposed method was applied to a case study related to 2018 Hurricane *** method was able to precisely identify events of varied sizes and densities before,during,and after the *** feasibility of the proposed method was qualitatively evaluated using the Silhouette coefficient and qualitatively *** proposed method was also compared to an implementation based on the standard density-based spatial clustering of applications with noise algorithm,where it showed more promising results.

关键词： Disaster management Hurricane Florence Natural language processing Spatio-temporal tweet analysis Tweet clustering Twitter

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