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Regional hard coral distribution within geomorphic and reef flat ecological zones determined by satellite imagery of the Xisha Islands,South China Sea

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Chinese Journal of Oceanology and Limnology 2017年第3期35卷 501-514页

作者：左秀玲苏奋振赵焕庭张君珏王琦吴迪 State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Collaborative Innovation Center of South China Sea Studies Nanjing 210093China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Key Laboratory of Hydrography and cartography of PLA Department of Hydrography and CartographyDalian Naval AcademyDalian 116018China

Coral reefs in the Xisha Islands （also known as the Paracel Islands in English）, South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geomorphic and ecological zones, essential for reefs management in the context of global warming and ocean acidification, is not well documented. We analyzed data from field surveys, Landsat-8 and GF-1 images to map the distribution of hard coral within geomorphic zones and reef fiat ecological zones. In situ surveys conducted in June 2014 on nine reefs provided a complete picture of reef status with regard to live coral diversity, evenness of coral cover and reef health （live versus dead cover） for the Xisha Islands. Mean coral cover was 12.5% in 2014 and damaged reefs seemed to show signs of recovery. Coral cover in sheltered habitats such as lagoon patch reefs and biotic dense zones of reef flats was higher, but there were large regional differences and low diversity. In contrast, the more exposed reef slopes had high coral diversity, along with high and more equal distributions of coral cover. Mean hard coral cover of other zones was 〈10%. The total Xisha reef system was estimated to cover 1 060 km2, and the emergent reefs covered -787 km2. Hard corals of emergent reefs were considered to cover 97 km2. The biotic dense zone of the reef flat was a very common zone on all simple atolls, especially the broader northern reef flats. The total cover of live and dead coral can reach above 70% in this zone, showing an equilibrium between live and dead coral as opposed to coral and algae. This information regarding the spatial distribution of hard coral can support and inform the management of Xisha reef ecosystems.

关键词： coral reef geomorphic zone remote sensing Xisha Islands South China Sea

Application of SAR Imagery in Submarine Topography Surveys

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Marine Science Bulletin 2004年第1期6卷 38-46页

作者：张宁川梁开龙桂力民 department of Hydrography and cartography Dalian Naval AcademyDalian 116018Liaonin China

An important research area in oceanographic surveying and mapping is to obtain submarine topography by remote sensing technique, especially by SAR imagery. In this article, problems related to SAR imagery are analyzed... 详细信息

关键词：地形测量海洋测量安全分析报告图象处理

Accessing the Potential of Satellite and Telemetric Data to Evaluate the Influence of the Heat Flux Exchange in the Water Column Mixing and Stratification

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International Journal of Geosciences 2012年第5期3卷 899-907页

作者： Enner Alcantara department of cartography Sao Paulo State University (UNESP) Presidente Prudente Brazil

The objective of this work is to evaluate the feasibility of moderate resolution satellite data estimating the surface heat balance in a tropical hydroelectric reservoir. Each component of the heat flux balance was computed using the MODIS (Moderate Resolution Imaging Spectroradiometer) water surface temperature (WST) level 2, 1 km nominal resolution data (MOD11L2, version 5) from 2003 to 2008. The consequence of the heat flux exchange in the water column thermal structure is also investigated. The passage of cold front over a region decreases the atmospheric pressure and air temperature, enhancing the relative humidity. The sensible flux presents a small variability but an increase occurs due to a convective turbulence caused by front passage. The latent flux decrease but insufficiently to cause a condensation, just the evaporation decreases. The upwelling events are the responsible to maintain the loss of heat after the cold front pas- sage.

关键词： Thermal Infrared Heat and Cooling Mixing Stratification

Analysing Mismatches in the Demand and Supply of Classrooms in the Basic and Secondary Education Sectors in Cameroon

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Journal of Geographic Information System 2022年第3期14卷 175-192页

作者： Aloysious Kohtem Lebga Aristide Yemmafouo Chretien Ngouanet Anehmbom Ghoutum Bienvenu Magloire Takem Mbi National Institute of cartography Yaoundé Cameroon department of Geography University of Dschang Yaoundé Cameroon

The present work analyzed the contribution of Cameroon’s public contracts and territorial planning policies toward the reduction of classroom disparities across the country. Many localities in Cameroon suffer due to misallocation of classrooms on one hand and inefficient public contracting-execution system on the other hand. This paper uses a hypothetico-deductive method to understand the nexus of public contracting-territorial planning within the educational sector in Cameroon. To do this we made use of existing infrastructural data collected from various Ministerial departments and public contracts data from 2016 to 2022. Findings show that there is a great disparity of existing classrooms, injustice in the allocation of classrooms and bad governance practices in the award and execution of allocated classrooms that directly contribute to this uneven repartition. At the national scale, the Centre and Littoral regions seem to be saturated with about 20,574 and 10,436 classrooms respectively, the Far North which is part of the Priority Education Zone is in dying need of about 11,293 classrooms while on the local or regional scale these two saturated regions show some degree of insufficiency in term of available classrooms. Therefore, much needs to be done by the Cameroonian authorities in order to ensure inclusive, equitable quality education and promote lifelong learning opportunities for all as stipulated by the Sustainable Development Goal 4.

关键词： Public Contracts Territorial Planning Territorial Disparities Governance Classroom Cameroon

Algorithm for Harmonic Tidal Analysis along T/P Tracks： Taking Differences of Observed Sea Surface Heights at Adjacent Points as Observations

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Geo-Spatial Information Science 2008年第1期11卷 17-20页

作者： XU Jun BAO Jingyang LIU Yanchun YU Caixia department of Hydrography and cartography Dalian Naval Academy 667 Jiefang Road Dalian 116018 China 不详

An algorithm （differential mode） is presented for the improvement of harmonic tidal analysis along T/P tracks, in which the differences between the observed sea surface heights at adjacent points are taken as observations. Also, the observation equations are constrained with the results of the crossover analysis; the parameter estimations are performed at 0.1° latitude intervals by the least squares. Cycle 10 to 330 T/P altimeter data covering the China Sea and the Northwest Pacific Ocean （2°-50° N,105°-150° E） are adopted for a refined along-track harmonic tidal analysis, and harmonic constants of 12 constituents in 8 474 points are obtained, which indicates that the algorithm can efficiently remove non-tidal effects in the altimeter observations, and improve the precision of tide parameters. Moreover, parameters along altimetry tracks represent a smoother distribution than those obtained by traditional algorithms. The root mean squares of the fitting errors between the tidal height model and the observations reduce from 11 cm to 1.3 cm.

关键词： satellite altimetry T/P harmonic tidal analysis differential mode

Redistribution of Soil Organic Carbon Triggered by Erosion at Field Scale Under Subhumid Climate,Hungary

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Pedosphere 2016年第5期26卷 652-665页

作者： Zoltan SZALAI Judit SZABO Jozsef KOVACS Erzsebet MESZAROS Gaspar ALBERT Csaba CENTERI Boglarka SZABO Balazs MADARASZ Dora ZACHARY Gergely JAKAB Geographical Institute Research Centre for Astronomy and Earth Sciences Hungarian Academy of SciencesBudapest 1112(Hungary) department of Environmental and Landscape Geography Eotvos Lordnd UniversityBudapest 1117(Hungary) department of Applied and Environmental Geology Eotvos Lordnd UniversityBudapest 1117(Hungary) department of cartography and Geoinformatics Eotvos Lordnd UniversityBudapest 1117(Hungary) department of Nature Conservation and Landscape Ecology Szent Istvdn UniversityGodollo 2100(Hungary)

Soil organic carbon(SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance(240–1 900 nm) and traditional physico-chemical *** representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg^(-1). Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.

关键词： Cambisol carbon sequestration diffuse reflectance selective erosion soil organic matter composition

A Collaborative Simplification Method for Multiple Coastlines Based on the Hierarchical Triangulation Network Partition

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Journal of Geodesy and Geoinformation Science 2020年第2期3卷 93-104页

作者： Lihua ZHANG Lulu TANG Shuaidong JIA Zeyuan DAI department of Military Oceanography and Hydrography&cartography Dalian Naval AcademyDalian 116018China

For the current automatic coastline generalization method,only one-line element is considered separately,but the relationship between the nearby elements is not effectively considered.A synergistic simplification method for multiple coastlines based on the hierarchical triangulation network partition(HTNP)is proposed in this ***,the constrained Delaunay triangulation is constructed to partition the regions that can be ***,a hierarchical binary tree model to structure the morphological characteristics of the above several coastlines and the spatial proximity between different coastlines is ***,the small curved and curved invisible parts of the coastline are deleted according to the visual constraints,and the narrow part between the coastline itself or the different coastlines is exaggerated appropriately,and the automatic simplification of the coastline is *** experimental results show that:①Relationships between the different coastlines are considered,and the shortcomings of considering the coastline separately are overcome;②Under the condition of the multiple coastlines in complex sea areas,the problem of collaborative simplification is solved,the quality of the coastlines are improved obviously,and the proposed method can be applied into more types of coastlines.

关键词： cartographic generalization coastline simplification hierarchy relationship synergistic simplification

Using Geospatial Information Component to Monitor the Watersheds along the Densu Basin in Ghana

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Journal of Geographic Information System 2016年第5期8卷 618-632页

作者： Clement Nyamekye Faruk Kwansah Nyame Samuel Anim Ofosu department of Civil Engineering Koforidua Polytechnic Koforidua Ghana COCOBOD Cartography and Survey Division Accra Ghana

The Densu basin is a coastal river catchment in southern Ghana and a typical rural community like all other rural settlements in Ghana. It is the only basin amongst 43 other basins of the country that supplies water to two regional capitals of Ghana, namely, the capital city of Ghana, Accra and Eastern regional capital, Koforidua. The qualities of these water resources vary naturally and widely depending on climate, season, and the geology of the bedrock, as well as anthropogenic activities. The primary aim of this research is to determine data requirements for efficient and cost-effective development of a Geographic Information System (GIS) to map and detect the extent of the sources of the watersheds and how to protect the environment for continuous supply of water. Among the Nine catchment areas, only one catchment WSA_05 (Koforidua Township) was determined to have a very high risk of being vulnerable and therefore required urgency to protect environment for continuous supply of water. Four catchment areas WSA_02 (Weija Dam), WSA_03 (Apedwa-Asafo), WSA_06 (Suhum) and WSA_09 (New Tafo) were determined to have a high risk of being affected and therefore there was the need to protect the environment for continuous supply of water. Ghana as a country will have to take a responsible step in protecting its water body and its environment to enable continuous and sustainable supply of water to its citizens. This study therefore reveals the state of the water users and how urgent it environment needs to be protected.

关键词： Watershed Geographical Information System (GIS) Densu Basin Water Service Areas (WSA) Land Use Land Cover (LULC)

Geoelectric Structure of the Crust along the Mbere Trough (South Adamawa) from Audio-Magnetotelluric Data

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International Journal of Geosciences 2013年第8期4卷 1215-1227页

作者： Ludovic Houetchak Kande Joseph Kamguia Jean Marie Tadjou Robert Nouayou department of Physics Faculty of Science University of Yaounde I Yaounde Cameroon National Institute of cartography Yaounde Cameroon

The South Adamawa trough represents a major structure associated to the tectonic activity in the Adamawa region. The Mbere and the Djerem troughs represent the eastern and the western parts of the South Adamawa trough respectively. The audio-magnetotelluric (AMT) method is used to study the Mbere trough and to bring out tectonic features that affect the basement of this region during the Cretaceous. From analysis and interpretation of AMT data, based on pseudo-section and geoelectric section, two geologic models are constructed across the trough at Belel and Nyambaka. Those models bring more information on the sediments thickness and the borders faults of the trough compared to previous studies. The results shows that the Mbere trough is dissymmetric, and bounded on its northern side by an intra-gneissic fault and on its southern side by two faults with at least one considered as a faulted contact between the granitic and gneissic rocks. The sediments filling of the trough are consist mainly of conglomerates on which lay sandstones. The thickness of these sediments is about 2060 m at Belel and decreases to about 1800 m at Nyambaka, with a low sandstones thickness, which does not exceed 360 m. The basement consists of granite in the South of the trough and gneiss in the North, with resistivity more than 10,000 Ω.m. The Moho is located between 25 and 35 km in the South Adamawa region.

关键词： Adamawa Trough Fault Resistivity Pseudo-Section Geoelectric Section