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1.
Tropical cyclones and their devastating impacts are of great concern to coastal communities globally. An appropriate approach integrating climate change scenarios at local scales is essential for producing detailed risk models to support cyclone mitigation measures. This study developed a simple cyclone risk-modelling approach under present and future climate change scenarios using geospatial techniques at local scales, and tested using a case study in Sarankhola Upazila from coastal Bangladesh. Linear storm-surge models were developed up to 100-year return periods. A local sea level rise scenario of 0.34?m for the year 2050 was integrated with surge models to assess the climate change impact. The resultant storm-surge models were used in the risk-modelling procedures. The developed risk models successfully identified the spatial extent and levels of risk that match with actual extent and levels within an acceptable limit of deviation. The result showed that cyclone risk areas increased with the increase of return period. The study also revealed that climate change scenario intensified the cyclone risk area by 5–10% in every return period. The findings indicate this approach has the potential to model cyclone risk in other similar coastal environments for developing mitigation plans and strategies.  相似文献   

2.
Climate change due to anthropogenic forcing through escalating greenhouse gas emissions and destruction of carbon sinks by deforestation is leading to floods and droughts affecting agriculture production. Global warming induces steric as well as eustatic rise in sea-level, by thermal expansion and addition of ice-melt water, respectively. Although the IPCC (2007) estimated a maximum possible sea-level rise of about 59 cm, more recent estimates show a global average rise of ≥1 m by the 2100 AD. The low-lying coastal zones are more vulnerable to rising sea levels as they face submergence or saltwater intrusion which affects the agriculture activities. Geomatics-based models on the possible impact of the predicted sea-level rise on coastal agriculture are necessary to initiate appropriate mitigation plans. The present study is an attempt in this direction taking the Andhra Pradesh (AP) coast as an example. The land use / land cover of the AP coast was mapped through the interpretation of IRS-P6 LISS III imagery from 2008. SRTM digital elevation models coupled with landform evidences have been used to interpolate contours at 0.5 m interval, although highly approximate, for the entire coastal region. If the sea level rises by 1.0 m, about 4040 km2 area including the present intertidal wetlands as well as the land between the present and future high tide lines would be affected along the entire 1030-km-long AP coast displacing about 1.67 million inhabitants and their economic activities, in about 351 revenue villages. The low-lying Krishna-Godavari delta region in the central part of the AP coast would be the worst affected zone as 2205 km2 of its area including about 1593 km2 under various types of agricultural activities is lying within the future high tide limit of 2.5 m elevation.  相似文献   

3.
The coastal zones around the world are very densely populated and hence heavily packed with related infrastructures. So, the territorial nations have obvious apprehensions against the IPCC SRES (Intergovernmental Panel on Climate Change, Special Report on Emission Scenario) predicted sea level rise, as it would cause flooding of the low lying coasts and also other related chains of environmental endangers. This has driven these nations to initiate research studies in multiple directions for scientifically evaluating the phenomenon and impacts of sea level rise using all possible technologies including the Geomatics which possesses unique credentials in geosystem mapping. But certain advanced virtues available with Geomatics technology are yet to be capitalized deservingly in this. In addition, almost all the earlier studies have focused only on the impacts of sea level rise (SLR) and not on the predicted shift of high tide line (HTL) and the related inter tidal activities, which would cause a series of environmental disaster. Hence, the present research study was undertaken in a test site of 750 km2 in central Tamil Nadu coast to visualize the areas prone to submergence due to predicted SLR and areas prone to environmental disasters/degradation viz. erosion, deposition, salination of agricultural lands, pollution of aquifers, etc. due to predicted shift of HTL, using digital elevation models derived from SRTM data (Shuttle Radar Topographic Mission), geomorphology and land use/cover maps interpreted using IRS P6 LISS IV satellite data. The paper narrates the certain newer concepts and methodologies adopted in the study and the results.  相似文献   

4.
The coastal lowlands in northern Jiangsu Province, China, is characterized by low relief and low water surface gradient in streams. The flooding stages are commonly lower than the high-tide level and the tidal range is relatively small. All these factors prohibit rapid discharge of floodwater and make the flood regimes here extremely sensitive to the sea level rise. The 1991 Plum Rain was examined, when precipitation was significantly higher than normal. The one-dimensional open-channel non-conservative flow model was used to simulate the stream flow in the channel network of studied area. GIS technology was used to delineate the maximum in undated area by analyzing the DEMs.  相似文献   

5.
The coastal lowlands in northern Jiangsu Province, China, is characterized by low relief and low water surface gradient in streams. The flooding stages are commonly lower than the high-tide level and the tidal range is relatively small. All these factors prohibit rapid discharge of floodwater and make the flood regimes here extremely sensitive to the sea level rise. The 1991 Plum Rain was examined, when precipitation was significantly higher than normal. The one-dimensional open-channel non-conservative flow model was used to simulate the stream flow in the channel network of studied area. GIS technology was used to delineate the maximum in undated area by analyzing the DEMs.  相似文献   

6.
In this study, we present an approach to estimate the extent of large-scale coastal floods caused by Hurricane Sandy using passive optical and microwave remote sensing data. The approach estimates the water fraction from coarse-resolution VIIRS and ATMS data through mixed-pixel linear decomposition. Based on the water fraction difference, using the physical characteristics of water inundation in a basin, the flood map derived from the coarse-resolution VIIRS and ATMS measurements was extrapolated to a higher spatial resolution of 30 m using topographic information. It is found that flood map derived from VIIRS shows less inundated area than the Federal Emergency Management Agency (FEMA) flood map and the ground observations. The bias was mainly caused by the time difference in observations. This is because VIIRS can only detect flood under clear conditions, while we can only find some clear-sky data around the New York area on 4 November 2012, when most flooding water already receded. Meanwhile, microwave measurements can penetrate through clouds and sense surface water bodies under clear-or-cloudy conditions. We therefore developed a new method to derive flood maps from passive microwave ATMS observations. To evaluate the flood mapping method, the corresponding ground observations and the FEMA storm surge flooding (SSF) products are used. The results show there was good agreement between our ATMS and the FEMA SSF flood areas, with a correlation of 0.95. Furthermore, we compared our results to geotagged Flickr contributions reporting flooding, and found that 95% of these Flickr reports were distributed within the ATMS-derived flood area, supporting the argument that such crowd-generated content can be valuable for remote sensing operations. Overall, the methodology presented in this paper was able to produce high-quality and high-resolution flood maps over large-scale coastal areas.  相似文献   

7.
Terrestrial ecosystems provide a number of vital services for people and society, such as food, fibre, water resources, carbon sequestration, and recreation. The future capability of ecosystems to provide these services is determined by changes in socio-economic factors, land use, atmospheric composition, and climate. Most impact assessments do not quantify the vulnerability of ecosystems and ecosystem services under such environmental change. They cannot answer important policy-relevant questions such as 'Which are the main regions or sectors that are most vulnerable to global change?’ 'How do the vulnerabilities of two regions compare?’ 'Which scenario is the least harmful for a sector?’This paper describes a new approach to vulnerability assessment developed by the Advanced Terrestrial Ecosystem Analysis and Modelling (ATEAM) project. Different ecosystem models, covering biodiversity, agriculture, forestry, hydrology, and carbon sequestration are fed with the same Intergovernmental Panel on Climate Change (IPCC) scenarios based on the Special Report on Emissions Scenarios (SRES). Each model gives insights into specific ecosystems, as in traditional impact assessments. Moreover, by integrating the results in a vulnerability assessment, the policy-relevant questions listed above can also be addressed. A statistically derived European environmental stratification forms a key element in the vulnerability assessment. By linking it to other quantitative environmental stratifications, comparisons can be made using data from different assessments and spatial scales.  相似文献   

8.
The shoreline is one of the rapidly changing landforms in coastal areas.They are the key element in coastal GIS and provide the most information on coastal land form dynamics.Therefore,accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features.The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India(where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami)by using Digital Shoreline Analysis System(DSAS),an extension of ArcGIS.Multidate IRS and Landsat Satellite data(1999,2001,2003,2005,2007,and 2009)are used to extract the shorelines.The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation.The rates of shoreline changes are estimated by three statistical methods,namely,End Point Rate(EPR),Linear Regression Rate(LRR),and Least Me-dian of Squares(LMS)by using DSAS.The study reveals that most of the study area has undergoing erosion.Both natural and an-thropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones.The coastal zones along the estuary have experienced accretion due to the littoral processes.The zones with headlands have more eroded than other zones along the study area.The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones.Improper and unsustainable sand mining may also lead to severe erosion problem along this area.The shoreline change rates are altered by various geological processes along the coast.Thus,the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards.It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and prom-ising its applications for coastal zone management in other regions.  相似文献   

9.
Digha coastal region in the northeastern part of the Bay of Bengal is potentially vulnerable to erosional hazard. The present study assessed the coastal erosion vulnerability along this 65 km long coastal stretch located between Rasulpur (Midnapur) and Subarnarekha (Balasore) estuarine complex, which had been subjected to anthropogenic intervention. Multi-resolution Landsat satellite imagery were used for shoreline change study from 1972 to 2010. During this period, accretion was recorded updrift of artificial structures, viz, seawall, groin, pylons and jetties; while, extensive erosion was recorded in downdrift areas of these structures. Assessment was subsequently divided into four categories ranging from “high erosion” to “accretion”. Data from several sources were compiled to map landuse and human activities in the coastal zone. This map was divided into four categories, ranging from “very high capital” to “no capital” landuse. Population density map of the surrounding coastal villages was generated using census data, and divided into four categories ranging from “high density area” to “very low density area”. Subsequently, coastal erosion vulnerability was assessed by combining coastal retreat with landuse type and population density in this study area using simple vector algebraic technique. Zones of vulnerability of different magnitude (viz., very high, high, moderate, and low) have been identified. Furthermore, calculation of “imminent collapse zone (ICZ)” shows that maximum values are around artificial structures and anthropogenic activities. The coastal erosion vulnerability map prepared from this study can be used for proper planning and management of this coastal region.  相似文献   

10.
近海海平面上升直接威胁人类生存,分析其成因不仅具有重要科学意义,而且能够为应对海平面上升提供相应策略。使用卫星测高、时变重力以及浮标观测研究2002—2020年近海300 km内海平面变化成因。由于时变重力在近海受到较为严重的泄漏误差影响,使用时变重力约束解模拟陆地质量变化对海洋质量的泄漏,其线性趋势约为0.68 mm/a。在季节和非季节尺度上,时变重力和浮标观测解释了卫星测高的结果,证明近海海平面平衡方程在季节和非季节时间尺度上能够被闭合。在长期变化趋势方面,卫星测高显示近海海平面上升速率为3.32±0.45 mm/a,而时变重力与浮标观测之和的速率为2.25±0.51 mm/a,两者之间存在约1 mm/a的速率差。鉴于该速率差高于估计的不确定度,认为当前在闭合近海海平面平衡方程长期趋势方面仍存在不小挑战,一方面近海比容实测数据较为稀少,很可能低估了长期趋势变化;另一方面,不完善的泄漏误差改正和陆地垂直运动改正也会影响近海海平面长期趋势变化。  相似文献   

11.
Coastal zone is very dynamic, being the meeting place of land and sea water. The development in coastal area and subsequent population growth have given rise to problems such as erosion, sedimentation, saltwater intrusion, degradation of natural resources, etc. Satellite data has proved to be more appropriate for change detections quantifying and monitoring coastal zones compared to conventional sources. An attempt is being made to elucidate the effect of shoreline changes with reference to the spatial and field data observed along the Tharangampadi area. The base map was prepared on 1:50,000 scale for delineation and identification of shoreline changes. The spatial variability of shoreline changes are studied using IRS 1B LISS-II 1991, IRS 1C LISS-III 2004 and IRS P6 LISS-IV and IRS 1D PAN merge data 2006. The corresponding Survey of India toposheets of 1852, 1972 and survey and land record village map of 1918 also supplemented for this study. The kind and extent of shoreline changes were investigated by using GPS during ground truth verification. The results are analyzed and presented in this paper. The study results revealed that 180 m receding of the shoreline occurred in the past 155 years.  相似文献   

12.
随着城市化进程加快,海岸带区域环境问题日益突出,与其相关的研究成为学术界的焦点。本文首先基于Web of Science核心数据库,以国家、关键词等信息为研究对象,应用Citespace的知识图谱梳理了海岸带相关研究的脉络,并对其进行了量化与可视化分析。然后通过总结不同时期的研究热点和演化过程,完善海岸带相关的研究,为今后的研究方向与角度提供参考与借鉴。结果表明,随着对海岸带地位特殊性的认识,越来越多的学者投入到海岸带的研究中。分析认为,应用大数据、云计算技术的研究方式及针对大尺度的海平面上升的研究、中等尺度的海岸带的城市生态相关的研究、较小尺度的激光雷达测深等研究是未来主要的研究方向。  相似文献   

13.
海岸带地区陆海图的差异分析   总被引：6，自引：0，他引：6  
海岸带是影响人类活动的重要地带.随着海洋经济的发展,海岸带专题图的需求日益增加.详细介绍了目前海岸带地区地形图和海图表示方法的各种差异,分析了产生这些差异的根本原因;阐述了消除地形图和海图差异的办法即新建海岸带地形图,编制海岸带地形图测量和编绘规范,编制海岸带地形图图式,统一海岸带地形要素的表示内容和表示方法.在此基础上根据不同的需要测绘海岸带地形图,为经济建设和社会发展提供有力的技术支持.  相似文献   

14.
海岸带是影响人类活动的重要地带。随着海洋经济的发展,海岸带专题图的需求日益增加。详细介绍了目前海岸带地区地形图和海图表示方法的各种差异,分析了产生这些差异的根本原因;阐述了消除地形图和海图差异的办法即新建海岸带地形图,编制海岸带地形图测量和编绘规范,编制海岸带地形图图式,统一海岸带地形要素的表示内容和表示方法。在此基础上根据不同的需要测绘海岸带地形图,为经济建设和社会发展提供有力的技术支持。  相似文献   

15.
Global sea level rise and local land subsidence might exacerbate the risk of flooding in coastal plains. Among other cities, this is also the case for the high-latitude city of St. Petersburg, which has long been threatened by flood events. To protect the urban area from storm surges, the Union of Soviet Socialist Republics (USSR) in 1978 approved the construction of the 25 km long Flood Prevention Facility Complex (FPFC), which was completed in 2011. The risk of flooding in the city area of St. Petersburg is amplified by the fact that large sections of the coastal area have been reclaimed from the sea. In this study, we investigate the temporal evolution of the ground displacement in St. Petersburg. To this end, we perform an extended analysis based on the application of a simplified version of the differential interferometric synthetic aperture radar technique, known as the minimum acceleration (MinA) approach. The MinA algorithm is a multi-satellite/multi-track interferometric combination technique that allows working with multiple sets of SAR images. The method allowed generation of time series of two-dimensional (2-D) (i.e. East-West and Up-Down) deformation of the terrain by processing two sequences of Sentinel-1A/B (S-1A/B) SAR images acquired from 2016 to 2018, along the ascending and descending flight passes. The Small BAseline Subset (SBAS) algorithm was independently applied to the two sets of SAR data to generate the relevant Line-Of-Sight (LOS)-projected ground deformation time series. Subsequently, the LOS-projected deformation products were geocoded and jointly combined. The results indicate that the deformation in the city is predominantly vertical (i.e. it is subsiding) with a maximum subsidence rate of about 20 mm/year corresponding to the newly sea-reclaimed lands. Finally, the error budget of the retrieved 2-D deformation time series has also been addressed.  相似文献   

16.
城市建设出现了地形图图式未规定的地物要素,地形测量、地理信息系统、数字制图技术的应用给图式的设计提出了新的课题,本文旨在探讨设计和修订图式的思路和方法。  相似文献   

17.
In the Netherlands, around 40% of the territory is below sea level. Rivers that flow through this land have to be constantly monitored to avoid flooding. To this end, terrain information is needed. At present, the relief information is acquired by means of photogrammetry, which makes the information expensive. Furthermore, it is estimated that at least 4 years are needed to collect the relief information of all river zones. A cheaper and faster alternative appears to be the use of laser measurements acquired from an aircraft. Thus, it is of great importance to determine if the user requirements, concerning information needed and related quality, can be fulfilled by high-density laser measurements. In this article, we assess the feasibility of using laser data to help generate a hydrodynamic model. This is needed to determine the effect of high water levels and of earthworks, such as removal of sand in river areas. The conclusion of this study is that as far as the test area is concerned, which appears to be a good representative of the fluvial regions in the Netherlands, the laser data allow one to recover the relief information needed for river management with the desired quality.  相似文献   

18.
Land subsidence due to underground resources exploitation is a well-known problem that affects many cities in the world, especially the ones located along the coastal areas where the combined effect of subsidence and sea level rise increases the flooding risk. In this study, 25 years of land subsidence affecting the Municipality of Ravenna (Italy) are monitored using Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) techniques. In particular, the exploitation of the new Sentinel-1A SAR data allowed us to extend the monitoring period till 2016, giving a better understanding of the temporal evolution of the phenomenon in the area. Two statistical approaches are applied to fully exploit the informative potential of the A-DInSAR results in a fast and systematic way. Thanks to the applied analyses, we described the behavior of the subsidence during the monitored period along with the relationship between the occurrence of the displacement and its main driving factors.  相似文献   

19.
海岸带作为连接海洋和陆地系统的特殊地理地带,与人类的生存与发展密切相关,但其自然和生态环境极其脆弱和敏感。气候变化和人类活动给海岸带环境带来了巨大压力,导致其生态环境不断恶化。随着技术的发展,近年来遥感技术已成为海岸带地理环境监测的重要手段之一,在海岸带规划、管理和保护中扮演着举足轻重的角色。本文对遥感技术在海岸带地理环境监测典型应用(土地利用/覆盖、土壤质量、植被、海岸线、水色、水深和水下地形及灾害)中的主要数据源、方法、结果和局限性进行归纳和总结,并对其未来发展提出展望。  相似文献   

20.
The main objective of the study is to identify groundwater potential zones in Thirumanimuttar basin with an integrated approach using Remote Sensing and geographical information system(GIS).FCC Image of Landsat TM 30 m resolution data and topographic maps has been used to generate thematic maps like geology,geomorphology,lineament and lineament density,drain-age,drainage density,and slope map of the study area.A number of geomorphic units such as Denudational hills,structural hills,Bajadas,Colluvial plain,Pediplain,Deep Pediment and Alluvial plains have been observed.A composite groundwater potential map has been generated as very high,high,medium,low and very low based on the groundwater availability area.The upper,mid-dle and downstream of the basins have been identified as potential zones for groundwater exploration.The regions of lineaments and intersecting lineaments proved for groundwater potential zones.The data generated was validated with field checks and ob-served to be in conformity with the same.  相似文献   

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