The tropical forest in south east Asia: Monitoring and scenario modeling using synthetic aperture radar data     

《Applied geography (Sevenoaks, England)》2013

Tropical forests play a major role in storing large carbon stocks and regulating energy, and water fluxes, but such forest cover is decreasing rapidly in spite of the policy attention on reducing deforestation. High-resolution spatiotemporal maps are unavailable for the forests in majority of the tropical regions in Asia because of the persistent cloud cover and haze cover. Recent advances in radar remote sensing have provided weather-independent data of earth surface, thus offering an opportunity to monitor tropical forest change processes with relatively high spatiotemporal resolutions. In this research, we aim to examine the tropical deforestation process and develop a spatial model to simulate future forest patterns under various scenarios. Riau Province from central Sumatra of Indonesia is selected as the study area; this province has received much attention worldwide because the highest CO₂ emission resulting from tropical deforestation has been recorded. Annual time series PALSAR data from 2007 to 2010 were analyzed for forest mapping and detecting land cover changes. A spatial model was calibrated using the Bayesian method. Modeling parameters were customized for the local subregions that allocate deforestation on the basis of their empirical relationships to physical and socioeconomic drivers. The model generated landscape spatial patterns mirrored the possible locations and extent of deforested areas by 2030 and provided time-series crucial information on forest landscape under various scenarios for future landscape management projects. The results suggested that the current deforestation process is in a critical stage where some subregions may face unprecedented stress on primary forest costing rivers and forest ecosystems by the end of 2020. The perspective views of Riau Province generated by the model highlighted the need for forest/environmental planning controls for the conservation of environmentally sensitive areas.  相似文献   

Using remote sensing and GIS to investigate the impacts of tourism on forest cover in the Annapurna Conservation Area,Nepal     

《Applied geography (Sevenoaks, England)》2013

Tourism is Nepal's largest industry, giving people in rural areas an alternative to subsistence farming. Tourism can have an impact on the forest cover of a region as trees provide firewood for cooking and heating and timber for building accommodation. In 1986 the Annapurna Conservation Area Project was established to ensure that tourism was managed more sustainably, which includes minimising its impact on the forest cover. This study assesses the impacts of tourism on the forest cover in the Annapurna region by comparing Landsat images from 1999 to 2011. This was achieved through spectral classification of different land cover and by assessing the change in forest cover in relation to increasing distances from tourism villages. A major problem with remote sensing in mountainous regions such as Nepal is shadow caused by the relief. This issue was addressed by only assessing areas which were free from shadow, which in effect meant a sample was used rather than the whole study region. The results indicate that there has been an 8 percent reduction in overall forest extent, but this change varies by region. In the northern, drier regions there has been a net increase in forest cover, while in the southern regions there has been a net reduction in forests. The influence of tourism facilities on forest is also variable. Around each of the tourism villages sampled there was a general trend of forest removal decreasing as the distance from each village increased, which indicates tourism does have a negative impact on forests. However, there was an opposite trend in the northern villages that were well inside the conservation area.  相似文献   

Beyond density: municipal expenditures and the shape and location of development     

Lyndsey A. Rolheiser  Chengzhen Dai 《Urban geography》2013,34(8):1097-1123

A clear understanding of the relationship between development patterns and municipal expenditures is complicated by how one chooses to quantify these patterns. Extant literature often employs a single density measure to capture the low-density nature of sprawl. While density provides an intuitive link to economies of scale and congestion costs, it fails to capture other spatial characteristics of sprawl related to centrality, connectedness, and mixed use that may influence municipal expenditures according to Smart Growth and New Urbanism advocates. This study uses Massachusetts orthoimagery data to construct multidimensional measures of residential and commercial land use patterns. Municipal expenditures associated with public works, fire, and police are regressed on multidimensional measures of land use as well as a number of demand controls. Findings indicate that economies and diseconomies do exist with respect to the multidimensional metrics considered. Support is mixed for development patterns emphasized by Smart Growth and New Urbanism advocates.  相似文献   

再议绿洲－沙漠过渡带——以策勒绿洲－沙漠过渡带为例   总被引：4，自引：0，他引：4       下载免费PDF全文

穆桂金  贺俊霞  雷加强  庞营军  邢文娟  杨发相  刘国军  毛东雷  岳健 《干旱区地理》2013,36(2):195-202

 被长期质疑的绿洲－荒漠过渡带在不断观测和丰富积累的基础上让我们有了一个完整的认识。以策勒绿洲为例对其进行剖析,作为绿洲－荒漠过渡带的一种典型类型,绿洲－沙漠过渡带可以界定为自绿洲边缘（人工防护体系或天然稀疏灌木林边界）到植被盖度为20%～25%的固定－半固定沙地为外缘边界（绿洲与流动沙漠之间）的荒漠地带。过渡带的内缘边界为绿洲外缘的人工防护体系,包括防风阻沙林带或天然稀疏灌木林。过渡带形成是因为从绿洲到外部荒漠存在水热环境因子的梯度变化,导致植被、土壤、地貌等综合景观展现出过渡特征,其组成与结构模式为：由绿洲向沙漠方向,稀疏灌木林（或边缘防护林体系）地－缓起伏灌草沉沙地－起伏灌丛沙堆和高起伏灌丛沙堆地。过渡带是乡土动植物重要的保留与保护地,是绿洲与沙漠间能流物流输送交换的缓冲带、绿洲的天然生态屏障,对地貌、土壤以及植被具有保护功能,且具有重要的固碳作用。  相似文献   

Early applications of geographical information systems at the Institute of Terrestrial Ecology     

NIGEL J. BROWN  DAVID A. NORRIS 《International journal of geographical information science》2013,27(2):153-160

Abstract

The Institute of Terrestrial Ecology (ITE) Digital Cartographic Service provides a range of services to the scientists of ITE (and others) including various techniques within the field of geographical information systems (GIS). This paper discusses work of this type as it is applied to specific ITE projects. The emphasis is very much on GIS applications to ‘real ecological science’ such as the ‘acid water’ problem and the change of forest areas into heathland. Some comments are made on fundamental GIS techniques, their use and limitations. At ITE, GIS applications are growing out of an existing use of digital mapping and remote sensing technologies; they have not purchased a GIS system ‘off the shelf.’  相似文献   

Exploring spatial data uncertainties in land‐use change scenarios     

N. Dendoncker  C. Schmit  M. Rounsevell 《International journal of geographical information science》2013,27(9):1013-1030

This paper evaluates errors and uncertainties in representing landscapes that arise from different data rasterization methods, spatial resolutions, and downscaled land‐use change (LUC) scenarios. A vector LU dataset for Luxembourg (minimum mapping unit: 0.15 ha; year 2000) was used as the baseline reference map. This map was rasterized at three spatial resolutions using three cell class assignment methods. The landscape composition and configuration of these maps were compared. Four alternative scenarios of future LUC were also generated for the three resolutions using existing LUC scenarios and a statistical downscaling method creating 37 maps of LUC for the year 2050. These maps were compared in terms of composition and spatial configuration using simple metrics of landscape fragmentation and an analysis of variance (ANOVA). Differences in landscape composition and configuration between the three cell class assignment methods and the three spatial resolutions were found to be at least as large as the differences between the LUC scenarios. This occurred in spite of the large LUC projected by the scenarios. This demonstrates the importance of the rasterization method and the level of aggregation as a contribution to uncertainty when developing future LUC scenarios and in analysing landscape structure in ecological studies.  相似文献   

Historical desertification of the Mu Us Sandy Land: A perspective from the Beidachi section     

YinZhou Huang  NaiAng Wang  HongYi Cheng  Ning M  TingTing Lai 《寒旱区科学》2013,5(3):0293-0300

Historical desertification of the Mu Us Sandy Land is linked to both environmental changes and anthropogenic activities. This paper reports on an analysis of grain size parameters as indicative of such changes in the southwestern area of the Mu Us Sandy Land. Combined with analysis of chronologies and historical records, our results indicate that Beidachi Lake and a nearby seasonal river have retreated continuously in history and that sand dunes appeared at approximately the end of the Ming dynasty. This study sheds new light on the understanding of spatial-temporal changes of the interior Mu Us Sandy Land in history and has great significance in revealing environmental changes of the interior region of the Mu Us Sandy Land.  相似文献   

Thermal infrared remote-sensing detection of thermal information associated with faults: A case study in Western Sichuan Basin, China   总被引：1，自引：0，他引：1  

Wenyuan WuLejun Zou  Xiaohua Shen  Shanlong LuNan Su  Fanli KongYoupu Dong 《Journal of Asian Earth Sciences》2012,43(1):110-117

Using enhanced land surface temperatures (LSTs) image retrieved from Landsat ETM+, this article shows that thermal information associated with faults have been detected. These anomalies may be provided by geothermal natural convection through faults and partially influence the ground surface thermal environment. The study area in southern segment of Longmen Mountains thrust belt of Western Sichuan Basin contains complex faults and folds with recent earthquake activity. In order to study the faults for future oil exploration, we use LST data retrieved from Landsat thermal infrared band to detect the thermal information associated with faults. The LSTs are enhanced by filtering out anthropogenic activity and influence land cover classes, and interpolating to contour map. The spatial patterns of the enhanced images revealed the spatial correspondence between the thermal information and the dip planes of faults when compared with the explanation profiles and geologic features obtained from the 3D-seismic geophysical data. The thermal-affected ranges calculated and the statistically significant of regression model also indicate the result that the thermal information located near the faults are consistent with the faults’ dip planes.  相似文献   

内蒙古科尔沁右翼中旗上侏罗统满克头鄂博组 木化石新资料   总被引：1，自引：0，他引：1  

付俊彧  宋维民  陶楠  庞雪娇  卞雄飞  吴桐  张志斌 《地质通报》2012,31(5):653-661

报道了首次在大兴安岭中南段侏罗系火山-沉积地层中发现的木化石。化石产于内蒙古自治区科尔沁右翼中旗地区满克头鄂博组中酸性火山碎屑沉积岩中,经沈阳地质矿产研究所张武研究员详细鉴定,有5属3个已知种和2个未定种。对新发现木化石的主要特征进行了描述,讨论了木化石的时代。综合分析所发现化石的组合特征,认为其时代属中晚侏罗世。这些木化石新材料为大兴安岭地区上侏罗统地层区域对比提供了新的古生物资料依据。  相似文献   

水准测量网监测在德州市地面沉降中的应用     

何国荣  冯在敏  冯克印  任翠爱  商婷婷  谭现锋 《山东地质》2012,(6):28-30

山东地面沉降灾害以鲁北平原最为严重,在德州地区的地面沉降已对当地人民的正常生产和生活构成了威胁,并制约了当地经济的可持续发展。通过建立水准测量网络及监测运行,查明了德州市地面沉降的规模和范围,研究成果表明工作区均存在地面沉降现象,截至2010年,德城区由于地下水开采强度大,地面沉降幅度最大,目前地面累计沉降量为-1186．9～-636．9mm,多年平均沉降速率为59．35mm／a,形成了以市区西北部为中心的地面沉降盆地。超量开采深层地下水是造成大规模地面沉降的重要因素。  相似文献