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Soil organic carbon stock explored by geo-spatial modeling at Sagar Island, India
Gouri Sankar Bhunia,Pravat Kumar Shit,Ramkrishna Maiti 대한공간정보학회 2016 Spatial Information Research Vol.24 No.5
Soil organic carbon (SOC) and organic carbon density (OCD) is an active indicator of soil fertility and productivity, and it fluctuates spatially and temporally. The main objective of the present study is to evaluate the spa- tial variability of SOC and OCD using geostatistics model as well as field methods at Sagar Island (Sundarban), India. Soil samples at the depths of 0–20 cm were collected from twenty plots at different season to estimate organic carbon concentrations and carbon density in the laboratory. Spatial distributions of SOC and OCD concentrations were esti- mated using ordinary kriging method. Remote sensing imagery and ground truth helped in identifying different features as well as land use/land cover correctly. Landuse are characterized by coastal water, sand, coastal wetland, salt marsh, agricultural fallow land, sparse vegetation, crop/paddy field, and mixed settlement area. The average value SOC were recorded as 2.80, 1.83, and 2.069 % in post-monsoon, pre-monsoon and monsoon season respec- tively. Semivariograms models of SOC and OCD in all seasons illustrated strong positive nugget values indicated short scale variability and sampling error. The coefficient of determination (R2 ) of the SOC model denoted as 0.71, 0.68 and 0.74 and for OCD calculated as 0.78, 0.67 and 0.83 at pre-monsoon, monsoon and post-monsoon season respectively. The results illustrated that mangrove forest portrayed highest amount of SOC concentration in both the pre-monsoon (1.05 kg/m2 ) and post-monsoon (0.94 kg/m2 ) season.
Channel dynamics associated with land use/cover change in Ganges river, India, 1989–2010
Gouri Sankar Bhunia,Pravat Kumar Shit,Dilip Kumar Pal 대한공간정보학회 2016 Spatial Information Research Vol.24 No.4
Shifting river courses and braiding in large rivers are part and parcel in fluvial morphology. The study aims at probing the changes of the Ganges river courses with accompanying land use/land cover characteristics. Here the changes that took place over a period ranging a couple of decades were recorded using multi-temporal Landsat 4–5 Thematic Mapper data. Meander geometry was precisely estimated. River course change pattern along with the changes in land use/land cover were studied over the period of 21 years (1989–2010). Results showed 0.14 km bank erosion and 0.85 km valley area was prone to erosion during the entire study period. The study exhibited the active channel area decreased by 22.88 km2 (0.33 % of the original river course) from 1989 to 2010. Land use characteristics showed settlement and plantation with settlement and crop lands were increased, whereas agricultural land was decreased in the study area. The overall kappa statistics were recorded as more than 0.84 during the study period. Rivers tend to maintain its high volume flow by eschewing additional silt load through bank overflow, called flash flooding; which is a natural process for any river to maintain the health of its thalweg.
Spatio-temporal analysis of COVID-19 in India – a geostatistical approach
Bhunia Gouri Sankar,Roy Santanu,Shit Pravat Kumar 대한공간정보학회 2021 Spatial Information Research Vol.29 No.5
Coronavirus (Covid) is a severe acute respiratory syndrome infectious disease, spreads primarily between human beings during close contact, most often through the coughing, sneezing, and speaking small droplets. A retrospective surveillance research is conducted in India during 30th January–21st March 2020 to gain insight into Covid’s epidemiology and spatial distribution. Voronoi statistics is used to draw attention of the affected states from a series of polygons. Spatial patterns of disease clustering are analyzed using global spatial autocorrelation techniques. Local spatial autocorrelation has also been observed using statistical methods from Getis-Ord Gi *. The findings showed that disease clusters existed in the area of research. Most of the clusters are concentrated in the central and western states of India, while the north-eastern countries are still predominantly low-rate of clusters. This simulation technique helps public health professionals to identify risk areas for disease and take decisions in real time to control this viral disease.
Freshwater fish resource mapping and conservation strategies of West Bengal, India
Bidhan Chandra Patra,Avijit Kar,Manojit Bhattacharya,Srikanta Parua,Pravat Kumar Shit 대한공간정보학회 2017 Spatial Information Research Vol.25 No.5
Explorations and Germplasm estimation of fish biodiversity in the freshwater bodies of India are being gradually updated and analysed with a number of new discoveries though a well-defined figure of existing freshwater fish species at regional and state level remains to be calculated. The freshwater resources of India are currently experiencing an alarming decline trend in term of piscine biodiversity due to several undesired factors and consequences a considerable portion of freshwater fishes have been categorized as Threatened category. West Bengal is now becomes one of the most significant states of freshwater fish producer in India. The research study workout and divide the West Bengal state into six major physiographic divisions along with the help of modern Geoinformatics techniques (ArcGIS 10.2, Google Earth and Global Mapper software for map making purpose). The present study deals with the freshwater fish resource, distribution and biodiversity assessment of entire part of West Bengal. Occurrence of 251 fish species belonging to 15 orders, 50 families have been noted during the study period of 2012–2016. It is evident that the members belonging to Cyprinifomes constitute 37% of the total fish fauna of the river. Fluctuation in occurrence and abundance of the species are influenced by several anthropogenic activities. The demand of proper management of conservation policy is highlights through our research work.