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1.
Floods in Malaysia have been increasing in frequency and magnitude as reflected in the Kelantan Flood event in 2014 that resulted in a huge loss of lives and properties. Whereas remote sensing (RS) and geographical information system (GIS) tools have been extensively applied in flood disaster management, there are few reports and studies on the impact of floods on the land use/land cover environment in a post-disaster assessment. In this study, an integrated modelling approach was developed that used Landsat 8 OLI TIRS (Operational Land Imager (OLI) and Thermal Infrared Sensor) data, flood indexing and classification processes to estimate the impact of flood on the environment. The Normalized Difference Flood Index-3 (NDFI3) is an improvement on NDFI2 that takes into account the effects of cloud shadow in the images when extracting flood index areas. The flood model developed showed good agreement when compared with flooded areas shown in SAR (synthetic-aperture radar) image. The results of the flood extent as a proxy for damage estimation showed that the total flooded area was 502.34 km2 for the Kelantan Flood event in 2014, with plantation and built-up area accounting for 43 and 34.6% respectively. The least affected land uses/land covers were deforested area and forest, which accounted for 12.2 and 10.2% respectively. The RS and GIS technique developed in this post-disaster damage assessment is effective, relatively inexpensive and simple to implement by local authorities in support of post-flood disaster planning and decision-making.  相似文献   

2.
Tropical cyclones are the most common natural disasters in coastal regions and are the most costly in terms of economic losses. Economic loss assessment is the basis for disaster prevention and alleviation and for insurance indemnification. We use data from 1970 to 2008 for Zhejiang Province, China, in this study evaluating economic losses. We convert direct economic losses from tropical cyclone disasters in Zhejiang Province into indices of direct economic losses. To establish our assessment model, we process disaster-inducing assessment factors, disaster-formative environments and disaster-affected bodies using the principal component analysis method, and we abstract the principal component as the input of a BP neural network model. We found in the actual assessments of five tropical cyclones affecting Zhejiang Province in 2007 and 2008 that the post-disaster loss assessment values of tropical cyclones were higher than the actual losses, but that for more severe storms, the gap was smaller. This reflects the beneficial effect of efforts toward disaster prevention and alleviation for severe tropical cyclones. Pre-assessments based on relatively accurate forecast values of wind and precipitation at the start of a tropical cyclone have been in accordance with the post-disaster assessment values, while the pre-assessment results using less accurate forecast values have been unsatisfactory. Therefore, this model can be applied in the actual assessment of direct economic loss from tropical cyclone damage, but increasingly accurate forecasting of wind and precipitation remains crucial to improving the accuracy of pre-assessments.  相似文献   

3.
利用遥感、DEM、基础地理信息、土地利用变更调查、社会经济统计等各类数据和专题图件,以平江县为例,构建湖南典型贫困区土地生态状况综合评估体系,对平江县土地生态状况进行综合评估,并计算各个元指标障碍度。结果表明,平江土地生态质量总体较好,大部分地区表现为优良状态,土地生态质量空间差异性较大,在空间上呈现北低南高、西低东高的趋势。影响平江县和各个乡镇土地生态状况的主要障碍因子为湿地比例、林地年退化率、土地利用类型多样性指数、耕地比例、植被覆盖度,个别乡镇的主要障碍因子还包括水面比例和人口密度。通过对平江县土地生态状况进行综合评估与分析,寻找影响其土地生态健康发展的主要障碍因子,提出相关建议,以实现土地可持续利用,为湖南典型贫困区土地生态状况评估提供科学研究方法。  相似文献   

4.
The cyclone wave parameters are predicted using Young’s parametric hurricane wave prediction model. The input cyclone tracks for this work are obtained from Fleet Naval Meteorology and Oceanography Center, USA. Extreme value analysis is carried out to obtain the wave heights and periods for 1 in 5, 10, 50 and 100 years return periods, respectively. The deep-water hindcast wave corresponding to 100 years from probable directions are allowed to propagate to Visakhapatnam coastal waters using nearshore spectral wind-wave mode. The offshore wave height for one in 100-year return period is 11.9 m, and the corresponding nearshore wave height at 10-m water depth varies between 4.6 and 5.6 m depending on the directional spreading. Weibull distribution is chosen to fit the 24 cyclonic data sets over a total period of 30 years (September 1972 to November 2002). This paper demonstrates usefulness of Young’s wave model for deep-water extreme wave hindcasting. Further, the results of the present study would be highly useful for assessing the design wave height for Visakhapatnam coast.  相似文献   

5.
A three-dimensional numerical model is described to study theresponse of a coastal ocean excited by a tropical cyclone in the Bay of Bengal. The numericalexperiments have been carried out using the model to understand the dynamics and thermodynamics ofthe ocean due to different cyclonic systems approaching in different directions. In the firstexperiment, the model is used to simulate the vertical thermal structure of the ocean as a response ofpassage of the less intensified 1997 cyclone, which was skirting the east coast of India before crossingthe Bangladesh coast. The simulations are compared with the buoy data available during the storm period.In the next experiment, it is considered an idealized cyclone with hurricane winds movingnormal to the east coast of India crossing between Visakhapatnam and Kakinada to evolve thermalstructure and currents of the ocean. A net decrease of the SST of 6–7 °C is simulated whenthe severe cyclonic storm moved over the coastal ocean.  相似文献   

6.
基于NDVI的新疆玛纳斯湖湿地植被覆盖度变化研究   总被引：1，自引：0，他引：1  
王丽春  焦黎  来风兵 《冰川冻土》2018,40(1):176-185
以2000年、2006年、2010年、2013年和2016年5期的Landsat遥感影像为基础数据源,基于像元二分模型反演了玛纳斯湖湿地植被覆盖度。通过动态度、转移矩阵对比不同时期各等级植被覆盖度的转化比例,分析植被变化的驱动力。结果表明： 2000-2016年,玛纳斯湖湿地植被覆盖度总体较差。极低植被覆盖度所占比例由19.6%增加到了46.3%,低植被覆盖度所占比例由60.6%减少到了28.7%,中植被覆盖度所占比例由9.4%减少到了4.6%,中高植被覆盖度相对变化较小,所占比例由2.9%增加到4.2%,高植被覆盖度所占比例由7.4%增加到16.2%。整个地区的荒漠盐碱土地和农田土地利用面积在逐渐增加,影响植被覆盖度和湖泊萎缩干涸的主要因素是过度利用水资源和人类活动对主要源流流域土地资源的大规模开发。  相似文献   

7.
新疆荒漠露天矿区生态受损及砾幕层重构方法研究   总被引：1，自引：0，他引：1  
露天矿开采过程中的岩土剥离、土地压占导致大面积的地表、植被及地下水系被破坏和景观格局的改变,带来一系列生态环境问题。西北荒漠矿区作为我国未来煤炭资源战略的重要接替区,若无针对性的生态修复对策,将会严重威胁到我国国土生态安全。选取西北荒漠区7座典型露天煤矿,采用实地调研与实证研究法、遥感影像法、比较研究法等,从地貌重塑、砾幕层重构、荒漠植被重建3方面进行研究。结果如下:(1)新疆7座露天煤矿均有不同程度的土地扰动情况,白石湖矿区土地压占情况最严重,达到1 190.3 hm2;五彩湾矿区土地占用面积最大,为2 251.0 hm2;将军戈壁土地挖损面积最严重,达到1 007.3 hm2;大南湖矿区裸地面积最多,达到20 164.2 hm2;伊犁露天煤矿周边植被较多,达到343.3 hm2;西黑山矿区周边交通用地最多,达到194.3 hm2。(2)选择最具有代表性的五彩湾露天矿区进行砾幕层研究,其砾幕层面积比例由2000年的60.12%下降到2010年的31.28%,再上升至2017年的42.75%。(3)五彩湾矿区生物量为12.53 g/(m2·a),景观多样性指数为0.219 3,景观优势度为1.780 7,景观均匀度为0.109 7,其生态承载能力较弱,生态体系阻抗干扰能力较差,且区域的生态完整性较低。(4)五彩湾矿区植被覆盖率在2000年至2005年呈现上升趋势,2005年达7.72%,2005年至2015年呈现下降趋势,2015年降至3.89%。总的来说,西北荒漠露天矿区生态受损程度较为严重,应以砾幕层重构为主,采取人工支持引导的方式,提高自然生态修复的速率与效果,使受损生境通过自身主动反馈,走向自发恢复的良性循环。  相似文献   

8.
Classifying inundation limits in SE coast of India: application of GIS   总被引：1，自引：0，他引：1  
A study on the possible inundation limit in SE coast of India was carried out using various physical, geological and satellite imageries. The coastal inundation hazard map was prepared for this particular region as it was affected by many cyclones, flooding, storm surge and tsunami waves during the last six decades. The results were generated using various satellite data (IRS-P6 LISS3; LANDSAT ETM; LANDSAT-5 ETM; LANDSAT MSS) and digital elevation models (ASTER GLOBAL DEM), and a coastal vulnerability index was generated for the entire coastal stretch of Nagapattinam region in SE coast of India. The coastal area which will be submerged totally due to a 1–5 m rise in water level due to any major natural disaster (tsunami or cyclone) indicates that 56–320 km2 will be submerged in this particular region. The results suggest that nearly 7 towns and 69 villages with 667,477 people will be affected and indicate that proper planning needs to be done for future development.  相似文献   

9.
This study discusses vegetation recovery and land cover change with reference to the Chiufenershan landslide, a major disaster caused by the Chichi earthquake, 21 September 1999. Image classification technology, landscape indicators from multi-temporal remotely sensed data and a field survey provide the data. Image differencing methods and threshold values coupled with pre- and post-quake satellite images were used. Multi-temporal images in combination with various vegetation indices were drawn on to classify land cover patterns and discuss differences and suitability of indices. Landscape indicators and field investigations fed into an investigation of vegetation recovery and landscape change. The study results show that the best image classification system is original wavebands coupled with a cropping management factor index (CMFI). The land cover analysis shows that areas of forest and grass are increasing and areas of landslide are decreasing. From the field investigation, because the left and right sides of the landslide area were not disturbed by the earthquake, their calculated similarity index is the highest (30.08%). Miscanthus floridulus is the most dominant pioneer plant at the landslide collapse area with an importance value index (IVI) of 63.6%.  相似文献   

10.
Remotely sensed thermal infrared (TIR) data have been widely used to retrieve land surface temperature (LST). LST is an important parameter in the studies of urban thermal environment and dynamics. In the study, an attempt has been made using LANDSAT 8 thermal imagery to compute LST and the associated land cover parameters viz; land surface emissivity (LSE), normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI) and normalized difference water index (NDWI). Landsat 8 TIRS band 10 & 11 (thermal bands) during 21 Oct. 2016, 22 Nov.2016, 24 Dec. 2016 and 09 Jan. 2017 were processed for LST analysis. However, band 5 & band 4 of the imagery was processed for NDVI, band 6 & band 5 for NDBI and band 2 & band 5 for NDWI analysis. LST has been derived from both the bands 10 &11 and validated by in-situ observations on the date and time of satellite overpass from the study area. Band 10 derived LST have shown much temperature difference while comparing with the in-situ observations. However, LST derived from band 11 found similar & close to the in-situ measurements. Relationship between band 11 results and in-situ observed measurements were developed, which has showing a strong correlation with (r2 = 0.991). Land surface emissivity were also evaluated which shows variation in different land cover surfaces like vegetation, settlement, forest cover and water body. The study has proven that land surface temperature derived from satellite band 11 is the actual surface temperature of the study area.  相似文献   

11.
The Yangtze River is the China’s longest river and the third-longest river in the world. The river’s source region in the Qinghai-Tibet Plateau is especially sensitive to global environmental change because of its high elevation and cold environment. Under the influence of global warming, aeolian desertified land has expanded rapidly in this area. To assess the trends in aeolian desertification from 1975 to 2005, remote-sensing and GIS technology were used to monitor the extent of aeolian desertification in 1975, 1990, 2000, and 2005. The data sources included Landsat multi-spectral scanner images acquired in 1975, Enhanced Thematic Mapper (ETM+) images acquired in 2000, and Thematic Mapper (TM) images acquired in 1990 and 2005. Images recorded between June and October were selected, when vegetation grew well, because aeolian desertified land was more easily recognized during this period. Thematic maps, including land use and geomorphologic maps, were used as supplementary data. Aeolian desertification maps (1:100000) were produced for each year from the Landsat images through visual interpretation. The area of aeolian desertified land increased by 2,678.43 km2 from 1975 to 2005, accounting for 8.8% of the total area of aeolian desertified land in 1975, an increase of 89.28 km2 a−1. Increasing mean annual temperature and the combination of a dry, cold, and windy climate in winter and spring were mainly responsible for the expansion of desertified land.  相似文献   

12.
This paper mainly deals with the integrated approach of remote sensing and Geographical Information System (GIS) to delineate groundwater prospective zones in Narava basin, Visakhapatnam region. The various thematic maps generated for delineating groundwater potential zones are geomorphology, geology, lineament density, drainage density, slope and land use/land cover (LULC). Weighted index overlay (WIO) technique is used to investigate a number of choice possibilities and evaluate suitability according to the associated weight of each unit. The integrated map of the area shows different zones of groundwater prospects, viz. very good (18.9% of the area), good (26.4% of the area), moderate (17.1% of the area) and poor (37.6% of the area). The categorization of groundwater potential was in good agreement with the available water column in the basin area.  相似文献   

13.
合山市矿山地质环境影响评价研究   总被引：3，自引：1，他引：2  
广西合山属于煤炭资源枯竭型城市,正在经历的市域经济转型与大规模城市建设,使得矿山地质环境影响评价成为一项基础性工作。将矿山地质环境影响评价划分为两个层次,即采矿活动对矿山地质环境影响评价和城市建设对地质环境的影响评价。选取矿山地质环境条件、矿山开采状况、矿山地质环境问题3个地质环境要素,地形地貌、植被覆盖率、岩土体工程特征、矿山分布密度、煤层倾斜角度、煤层采深采厚比、土地资源破坏强度、水资源破坏强度、地质灾害发育强度9个评价指标,首先应用模糊综合评价模型进行了第一层次的矿山地质环境影响评价,然后采用综合指数评价模型进行了第二层次的地质环境影响评价,结果显示,影响严重区、较严重区、一般区分别为62.87,118.84,175.99km2,各占市域面积的17.6%、33.2%、49.2%。评价结果可作为合山市矿山地质环境综合治理的重要依据。  相似文献   

14.
The methodology for assessing the vegetation damaged by the Wenchuan earthquake by using the technologies of remote sensing and GIS was discussed in Dujiangyan city of Sichuan Province, China. The model of extracting vegetation from CBERS images was formulated using the differentiation knowledge of vegetation and non-vegetation discovered by image analysis and geographic analysis. The damage degree index (DDI) of the vegetation was defined here, which was the difference of the normalized difference vegetation index before the earthquake and that after earthquake. The China-Brazil Earth Resource Satellite (CBERS)-02’s images acquired, respectively, on 6 May and 27 June 2008, the model of extracting vegetation, and DDI were used to obtain the information about the area and degree of the damage vegetation in the study. There was 87.94 square kilometers vegetation damaged by Wenchuan earthquake, which accounted for 7.9% of the total area in Dujiangyan city. The area percentage of the damage vegetation in each grade related strongly and positively to the elevation grade and slope grade and weakly related to the aspect type. The distribution characteristics of the damage vegetation were useful for making plan of restoring vegetation here.  相似文献   

15.
在全球变化的背景下,定量区分人类活动和气候波动对干旱区植被的影响具有重要意义。采用多种统计学方法,分析了我国西北干旱区1990-2010年土地利用/覆被变化（LUCC）和1982-2010年归一化植被指数（NDVI）的时空变化特征,并定量评估了LUCC对NDVI变化的影响。结果表明：1990-2010年,西北干旱区耕地增加量最多,高达13 476 km2,其次是林地和水域,各地类增加的面积主要来自草地（12 590 km2）和未利用地（6 025 km2）。各土地类型变化速度快慢依次为：耕地 > 建设用地 > 水域 > 林地 > 草地 > 未利用地。2000-2010年,研究区土地利用程度综合指数（0.79）明显高于1990-2000年（0.23）,表明近年来人类活动对土地利用变化的影响程度显著增强。1982-2010年,西北干旱区NDVI呈增加态势,但近年来（2002-2010年）NDVI略有下降。其中,1990-2000年,LUCC对西北干旱区NDVI总变化的贡献率较低,仅为2.9%;而1990-2010,LUCC的贡献率为26.7%,表明气候变化对植被指数变化的贡献率高达73.3%。  相似文献   

16.

Coal mining has serious impacts on local environment, including damage to the land and soil by subsidence, damage to ground-water systems through the fracturing and subsiding of overlying rocks, contamination of surface waters with acid mine drainage, and pollution of the atmosphere by release of toxic gases. The damage to ground water and its consequent impacts on the regional environment is the core of research of the coal mining from the perspective of environment protection. The present paper focuses on the changes of surface vegetation coverage, the pollutants released from pit coal power plants, and the damages to the ground aquifers induced by mining activities in arid Eastern Junggar coalfield of China. At first, the authors investigated the changes of surface vegetation coverage, since mining began in the 2000s using Landsat data. Results show that the low surface vegetation coverage (grade 1 plus grade 2) in the southern part of the region decreased from 11.62?×?108 m2 in 2003 to 9.57?×?108 m2 in 2017 (?17.6%), while it increased from 11.58?×?108 m2 in 2003 to 12.70?×?108 m2 in 2017 (+?9.7%) in the eastern part. The high surface vegetation coverage (grade 3 plus grade 4) in the southern part increased from 1.94?×?108 m2 in 2003 to 4.00?×?108 m2 in 2017 (+?106.2%), while it decreased from 4.39?×?108 m2 in 2003 to 3.26?×?108 m2 in 2017 (?25.74%) in the eastern part. The data of annual precipitation during the same period in this area show that the changes of surface vegetation coverage have less relationship with the annual precipitation, which indicates that the mining activities is probably the major factor for that. Second, a statistic of air pollutants generated from pit coal power plants was made based on data of references. Results show that the estimated gaseous pollutant emissions increased as 865.23 tons of smoke particles, 5940.73 tons of SO2, and 7584.48 tons of NO2 in 2013, which increased rapidly with 9.73 times the smoke particle, 21.69 times the SO2, and 9.24 times the NO2 than that of 2007. And then, the physical and numerical simulation of the damage of mining activities to aquifers was made to show the permeability of the reference points of overlying aquifers varies associated with mining activities. Results show that the porous rock matrix permeability has a negative relationship with fluctuation during mining, while the fracture permeability shows a positive one. Finally, a case investigation in southern area surrounding this coalfield was illustrated. Result shows that the local ground-water level decreased by 16 m difference from the altitude level of?+?774 m in 2003 to?+?758 m in 2013. Data and results from this study presented the already and the potential pollutions and damages to local environment induced by the mining activities in this region.

  相似文献   

17.
Windblown dust originating in China and Mongolia causes health effects and agricultural damage in its source areas and causes Asian dust events in Japan. An early warning system that could be combined with weather forecasts would be helpful in preventing serious damage. However, it is difficult to specify source areas of dust with current dust modeling systems because land surface information, including vegetation coverage and land surface soil water content, is inadequate. To find and monitor dust source regions, a semi-real-time dust erodibility map was developed based on MODIS satellite data that focuses particularly on the threshold wind speed in a target area of northeast Asia including China and Mongolia (35°–50°N, 75°–120°E). The mapping system incorporates satellite data on snow cover, areas of frozen soil, surface soil water content, and vegetation cover.  相似文献   

18.
Using the HURDAT best track analysis of track and intensity of tropical cyclones that made landfall over the continental United States during the satellite era (1980?C2005), we analyze the role of land surface variables on the cyclone decay process. The land surface variables considered in the present study included soil parameters (soil heat capacity and its surrogate soil bulk density), roughness, topography and local gradients of topography. The sensitivity analysis was carried out using a data-adaptive genetic algorithm approach that automatically selects the most suitable variables by fitting optimum empirical functions that estimates cyclone intensity decay in terms of given observed variables. Analysis indicates that soil bulk density (soil heat capacity) has a dominant influence on cyclone decay process. The decayed inland cyclone intensities were found to be positively correlated with the cube of the soil bulk density (heat capacity). The impact of the changes in soil bulk density (heat capacity) on the decayed cyclone intensity is higher for higher intensity cyclones. Since soil bulk density is closely related to the soil heat capacity and inversely proportional to the thermal diffusivity, the observed relationship can also be viewed as the influence of cooling rate of the land surface, as well as the transfer of heat and moisture underneath a land-falling storm. The optimized prediction function obtained by statistical model processes in the present study that predicts inland intensity changes during 6-h interval showed high fitness index and small errors. The performance of the prediction function was tested on inland tracks of eighteen hurricanes and tropical storms that made landfall over the United States between 2001 and 2010. The mean error of intensity prediction for these cyclones varied from 1.3 to 15.8 knots (0.67?C8.12?m?s?1). Results from the data-driven analysis thus indicate that soil heat flux feedback should be an important consideration for the inland decay of tropical cyclones. Experiments were also undertaken using Weather Research Forecasting (WRF) Advanced Research Version (ARW ver 3.3) to assess the sensitivity of the soil parameters (roughness, heat capacity and bulk density) on the post-landfall structure of select storms. The model was run with 1-km grid spacing, limited area single domain with boundary conditions from the North American Regional Reanalysis. Of different experiments, only the surface roughness change and soil bulk density (heat capacity) change experiments showed some sensitivity to the intensity change. The WRF results thus have a low sensitivity to the land parameters (with only the roughness length showing some impact). This calls for reassessing the land surface response on post-landfall characteristics with more detailed land surface representation within the mesoscale and hurricane modeling systems.  相似文献   

19.
The present paper is an attempt to integrate a semi-automated object-based image analysis (OBIA) classification framework and a cellular automata-Markov model to study land use/land cover (LULC) changes. Land use maps for the Sarab plain in Iran for the years 2000, 2006, and 2014 were created from Landsat satellite data, by applying an OBIA classification using the normalized difference vegetation index, salinity index, moisture stress index, soil-adjusted vegetation index, and elevation and slope indicators. The classifications yielded overall accuracies of 91, 93, and 94% for 2000, 2006, and 2014, respectively. Finally, using the transition matrix, the spatial distribution of land use was simulated for 2020. The results of the study revealed that the number of orchards with irrigated agriculture and dry-farm agriculture in the Sarab plain is increasing, while the amount of bare land is decreasing. The results of this research are of great importance for regional authorities and decision makers in strategic land use planning.  相似文献   

20.
The Thornthwaite Memorial, Synthetic, and Carnegie Ames Stanford Approach (CASA) models, with inputs from SPOT-VGT-S10 NDVI data, meteorological data (precipitation, temperature, solar radiation), and land use data were used to estimate the values of net primary productivity (NPP) from 1999 to 2007 in China’s Shiyanghe Basin. The human appropriation of NPP, which represents the difference between potential NPP predicted using the climatic models and actual NPP calculated using the CASA model, served as the indicator of human intervention in the evolution of productivity of the land. Analysis showed that 78.9% (~9,172 km2) of the degradation occurring in the Shiyanghe Basin was caused by human activities versus 15.0% (~1,752 km2) that was caused by climatic factors, whereas 16.9% (~6,404.5 km2) of the vegetation restoration resulted from human activities versus 49.7% (~18,881 km2) that resulted from climate changes. Human activity played a key role in vegetation restoration in the central areas of the basin and in determining land degradation in the southwestern and northeastern areas. In addition, climate significantly controlled the vegetation restoration in the southwestern and northeastern areas and controlled land degradation in the central area.  相似文献   

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