Urban–agricultural water appropriation: the Hyderabad, India case

With the urbanisation drive comes steady growth in urban water demand. Although in the past this new demand could often be met by tapping unclaimed water sources, this option is increasingly untenable in many regions where little if any unclaimed water remains. The result is that urban water capture, and the appropriation of associated physical and institutional infrastructure, now often implies conflict with other existing uses and users. While the urbanisation process has been studied in great depth, the processes and, critically, impacts of urban water capture and appropriation are not well researched or understood. This paper undertakes a critical examination of the specific case of Hyderabad, one of India's fastest growing cities, to shed light more generally on the process of water capture by cities and the resultant impacts on pre-existing claims, particularly agriculture. It does this by examining the history and institutional response to Hyderabad's urban–rural water contest; how the results of that contest are reflected in surface and groundwater hydrology; and the eventual impacts on agriculture. The findings show that the magnitude, and sometimes even direction, of impact from urban water transfer vary in space and time and depend on location-specific rainfall patterns, the nature of existing water infrastructure and institutions, and farmers' adaptive capacities and options, notably recourse to groundwater. Broader consideration of the specific findings provides insights into policy mechanisms to reduce the possible negative impacts from the global, and seemingly inexorable, flow of water to the world's growing cities.     

Texture-based identification of urban slums in Hyderabad, India using remote sensing data

This paper outlines a methodology to identify informal settlements out of high resolution satellite imagery using the concept of lacunarity. Principal component analysis and line detection algorithms were applied alternatively to obtain a high resolution binary representation of the city of Hyderabad, India and used to calculate lacunarity values over a 60 × 60 m grid. A number of ground truthing areas were used to classify the resulting datasets and to identify lacunarity ranges which are typical for settlement types that combine high density housing and small dwelling size - features characteristic for urban slums in India. It was discovered that the line detection algorithm is advantageous over principal component analysis in providing suitable binary datasets for lacunarity analysis as it is less sensitive to spectral variability within mosaicked imagery. The resulting slum location map constitutes an efficient tool in identifying particularly overcrowded areas of the city and can be used as a reliable source in vulnerability and resilience assessments at a later stage. The proposed methodology allows for rapid analysis and comparison of multi-temporal data and can be applied on many developing urban agglomerations around the world.     

城市再生视野下的棚户区改造实践问题

棚户区改造的目的是为了改善城市面貌和居民居住环境,提高城市品位和居民生活质量.目前,我国城市开展了大规模棚户区改造工程,然而大多数改造工作重心仍以拆建房屋为主,对棚户区的系统改建不足.针对这一问题,从棚户区改造与城市再生的关系入手,结合国内外大量棚户区改造的经验与教训,强调棚户区的改造不仅是单纯意义上的物质再生,更是涵盖经济复兴、社区重构、文化重建的社会再生.以辽宁省阜新市棚户区改造作为实证案例进行分析,指出当前棚户区改造中存在的诸多问题.在棚户区改造中,需要将建筑、就业、环境、文化、社会等因素融合一起,以促进城市再生与可持续发展.     

热带森林覆被的时空动态评价——以印度Malkangiri district of Orissa为例

Tropical forests have been recognized as having global conservation importance. However,they are being rapidly destroyed in many regions of the world. Regular monitoring of forests is necessary for an adaptive management approach and the successful implementation of ecosystem management. The present study analyses the temporal changes in forest ecosystem structure in tribal dominated Malkangiri district of Orissa,India,during 1973-2004 period based on digitized forest cover maps using geographic information system (GIS) and interpretation of satellite data. Three satellite images Landsat MSS (1973),Landsat TM (1990) and IRS P6 LISS III (2004) were used to determine changes. Six land cover types were delineated which includes dense forest,open forest,scrub land,agriculture,barren land and water body. Different forest types were also demarcated within forest class for better understanding the degradation pattern in each forest types. The results showed that there was a net decrease of 475.7 km2 forest cover (rate of deforestation = 2.34) from 1973 to 1990 and 402.3 km2 (rate of deforestation = 2.27) from 1990 to 2004. Forest cover has changed over time depending on a few factors such as large-scale deforestation,shifting cultivation,dam and road construction,unregulated management actions,and social pressure. A significant increase of 1222.8 km2 agriculture area (1973-2004) clearly indicated the conversion of forest cover to agricultural land. These alterations had resulted in significant environmental consequences,including decline in forest cover,soil erosion,and loss of biodiversity. There is an urgent need for rational management of the remaining forest for it to be able to survive beyond next decades. Particular attention must be paid to tropical forests,which are rapidly being deforested.     

Assessment of spatial and temporal dynamics of tropical forest cover: A case study in Malkangiri district of Orissa, India

Tropical forests have been recognized as having global conservation importance. However, they are being rapidly destroyed in many regions of the world. Regular monitoring of forests is necessary for an adaptive management approach and the successful implementation of ecosystem management. The present study analyses the temporal changes in forest ecosystem structure in tribal dominated Malkangiri district of Orissa, India, during 1973–2004 period based on digitized forest cover maps using geographic information system (GIS) and interpretation of satellite data. Three satellite images Landsat MSS (1973), Landsat TM (1990) and IRS P6 LISS III (2004) were used to determine changes. Six land cover types were delineated which includes dense forest, open forest, scrub land, agriculture, barren land and water body. Different forest types were also demarcated within forest class for better understanding the degradation pattern in each forest types. The results showed that there was a net decrease of 475.7 km2 forest cover (rate of deforestation = 2.34) from 1973 to 1990 and 402.3 km2 (rate of deforestation = 2.27) from 1990 to 2004. Forest cover has changed over time depending on a few factors such as large-scale deforestation, shifting cultivation, dam and road construction, unregulated management actions, and social pressure. A significant increase of 1222.8 km2 agriculture area (1973–2004) clearly indicated the conversion of forest cover to agricultural land. These alterations had resulted in significant environmental consequences, including decline in forest cover, soil erosion, and loss of biodiversity. There is an urgent need for rational management of the remaining forest for it to be able to survive beyond next decades. Particular attention must be paid to tropical forests, which are rapidly being deforested.     

Satellite remote sensing for monitoring of vanishing seagrass in Swedish coastal waters

Jon Martin Trolldalen: On the fringe - a systems approach to the evolution of the environment and agricultural production in The Gambia, West Africa, 1948-1983. Dr. scient. thesis. Department of Geography, University of Oslo, 1986.     

城市暴雨内涝综述：特征、机理、数据与方法

建成环境的高空间异质性与致灾过程的复杂性给城市暴雨内涝研究带来巨大的挑战,具体表现为模型代表性不够、计算效率低、基础数据和验证数据匮乏。以机器学习为代表的人工智能技术、高分遥感和互联网大数据的快速发展则为城市暴雨内涝研究提供了新的契机。论文结合人工智能、高分遥感和互联网大数据等新技术发展,从特征、机理、数据与方法4个维度对暴雨内涝的研究现状和发展趋势进行了系统总结,主要结论包括：① 暴雨内涝具有短历时性、空间散布性、连锁性和突变性,其热点呈现空间上的动态迁移特征。② 降雨时空特征和城市化程度决定暴雨内涝灾害的量级,地形条件尤其是微地形则决定发生位置和内涝频率。地形控制作用指数(topographic control index, TCI)对暴雨内涝发生位置具有良好的指示能力。③ 排水管网、高精度地形和不透水面分布是暴雨内涝模拟的关键基础数据;降雨过程的高时空变异性是暴雨内涝近实时预报预警的主要瓶颈,需要充分利用天气雷达观测提高其精准度;互联网众包大数据是获取高空间覆盖度暴雨内涝灾情信息的新途径,但也面临不同类型信息融合、提炼和质量控制的挑战。④ 结合水动力模拟与机器学习可建立兼具物理基础和计算效率的暴雨内涝模拟方法,是实现近实时模拟与快速预报预警的有效途径。     

Satellite imagery activism: Sharpening the focus on tropical deforestation

Since the first land remote sensing satellite was launched in the early 1970s, government agencies, private companies and research institutions have used satellite imagery data for a growing range of civil and commercial applications focused on natural resource management and exploitation, and environmental monitoring. The global diffusion of remote sensing expertize, along with growing public access to satellite images, has created conditions for improving levels of global transparency. One aspect of this global transparency is the advent of new users of imagery data – or 'imagery activists'– including, among others, issue-oriented nongovernmental organizations (NGOs), media groups, multinational organizations and academic researchers who now are able to access satellite imagery in order to draw domestic and international attention to particular public policy concerns. This paper broadly surveys the contemporary phenomenon of satellite imagery activism and outlines the main challenges facing imagery activists, particularly in relation to deforestation and other forest monitoring issues.     

海岛型城市扩展的生态效应分析——以厦门岛为例

利用Landsat卫星影像,采用新型遥感生态指数(RSEI)对海岛型城市厦门在不同时期的生态变化进行研究,以期揭示城市的快速发展对城市生态质量的影响。研究结果表明,1993~2009年,厦门岛的城市建筑用地虽经过大幅扩张,但并没有造成生态质量的大幅下滑,其RSEI生态指数值仅略为下降。分析表明,这主要是得益于厦门城市发展的科学规划。但是厦门岛西北部的生态较差,是今后进一步改善生态的重点地区。     

Satellite dataset analysis of recent vegetation variation in Tibet region

This research investigates the recent distribution variation trends of vegetation in the Tibet region using Normalized Difference Vegetation Index (NDVI) data from 2000 to 2007. It also discusses the causes of vegetation degradation in typical regions (such as Nagqu) based on climatic conditions, human activity, and other influencing factors. Results show that the areas with the best vegetation cover are in Nyingchi and the southern part of Shannan, followed by Chamdo, the Lhasa area, and the eastern part of Nagqu. Vegetation in various regions exhibits significant seasonal differences. The vegetation status has improved in some parts of the Tibet region in the past few years, while the areas with the most serious degradation are in the middle and southern parts of the Nagqu region. On average, distinct vegetation degradation occurred between 2003 and 2006 in the whole Tibet region but vegetation has been increasing since 2006. The vegetation cover in summer basically determines the annual vegetation status. An increase in precipitation and decrease in wind speed generally corresponds to an increase in vegetation cover. The reverse is also true: a decrease in precipitation and increase in wind speed correspond to the decrease in vegetation cover. NDVI is thus positively related to temperature and precipitation but has a negative relation with wind speed. Increasing temperature and decreasing precipitation have led to the present vegetation degradation in Nagqu, and vegetation in all of these regions has been affected by growth of human population, intensified urbanization, livestock overgrazing leading to the proliferation of noxious plants, extraction of underground minerals and alluvial gold, extensive harvesting of traditional Chinese medicinal plants [e.g., Cordyceps sinensis, Caladium spp., and saffron crocus (Crocus sativus)], and serious rodent and other pest damage.     

包尔图地区Aster遥感岩性提取

介绍光谱排序编码法的原理并对其进行精度验证:在14种矿物的56个样品中最高精度为100%,最低为57%,平均为79.4%;分别提取包尔图地区以方解石、Al-OH Mg-OH和石英为主的岩石分布状况,与该区地质图对比结果表明,其分布与实际情况大体相同,从而证实了光谱排序编码法的目标提取能力。     

旧城改造与城市热岛效应关系的遥感研究——以福州市苍霞片区为例

随着城市建设的快速发展,老城区改造已成为城市发展的重点工程之一。福州市近十几年来对原有旧城区中的棚屋区进行了大规模的改造,改善原有的居住条件。利用遥感技术重点研究和评价了福州市苍霞片区棚屋区改造前后的热环境变化,利用系列Landsat TM影像反演了该区1986年、1996年和2006年的地表温度、不透水面和植被等信息,计算了城市热岛比例指数(URI),并对该区改造前后热岛效应的时空变化进行了全面分析,探讨了其产生的主要原因。研究表明,不透水面与地表温度呈指数相关关系,高不透水面比例地区温度上升比低不透水面比例地区更快。总的看来,福州市苍霞片区通过棚屋区改造,热岛效应有了明显的缓解,在这20 a间,城市热岛比例指数从0.648下降到0.245。福州市苍霞棚屋区的重新规划和改造对缓解该片区的城市热岛效应起到了积极的作用。     

经济欠发达地区中心城市空间拓展分析——以南充市为例

以四川省南充市为例,探讨了西部经济欠发达地区中心城市的空间拓展规律。基于多时相Landsat TM遥感数据和GIS的定量研究方法,以城市分形理论为基础,结合对城市实体地域空间在不同方向上的拓展分析,系统探讨了南充城市空间在不同时期的形态特征。通过人机交互的监督分类方法,提取了1988、1993、1999、2002和2007年5个年份的南充中心城市实体地域数据,在GIS中进行了叠加。采用半径法进行城市分形研究,发现各个时期南充城市总体上存在分形特征,但维数存在两个标度区,而且标度区之间的维数具有跳跃性,以此判断出城市在不同阶段的增长动力存在差异——从自然增长主导的扩张模式向多种增长力量共同作用的综合模式演化。在对南充城市实体地域进行分象限拓展分析后,发现南充城市在演化过程中存在明显的方向性,总体趋势为东北-西南的轴向拓展,并以此为基础建立了城市空间扩展模型。     

Regimes of spatial ordering in Brazil: Neoliberalism,leftist populism and modernist aesthetics in slum upgrading in Recife

This paper shows how regimes of spatial ordering in Brazil are produced by the entangling of neoliberalism, leftist populism and modernist visions. The paper focuses on Prometrópole, a slum upgrading project in Recife funded by the World Bank, which commenced in 2007. In this project, the neoliberal dimension manifests in the idea that the state, private companies and citizens together are responsible for (re)constructing urban space, and further, that beneficiaries should behave as autonomous citizens, taking responsibility for their new living environment. The leftist political dimension is seen in participatory procedures to involve the target population from project design through to implementation, in expectation of their cooperation with the government. The modernist aesthetics – of straight lines, open spaces and visible order – informs the project design with the requirement to use the new houses and public spaces according to the standards of ‘modern civilization’. As our research shows, such a regime of spatial ordering clashes with the livelihoods of the urban poor, whose quality of life might even deteriorate as a result of the intervention. Furthermore, so‐called participatory procedures fail to grant the target population any real influence in creating their environment. Consequently, these residents of the new housing estate drastically reconstruct their private and public areas, reappropriating the urban space and contesting the regime of spatial ordering imposed upon them.     

基于卫星遥感信息的吉林省西部草地退化分析

利用 1996年和 1986年秋季陆地卫星TM数据 ,将计算机监督分类与非监督分类识别方法结合应用进行草地的解译 ,改进算法 ,改善遥感图像的识别精度。试验研究结果表明 :吉林省西部草原生态环境在恶化 ,草地面积平均每年减少 4.5× 10 4hm2 ,草地退化严重 ,退化草地面积已占草地总面积的 81.1%,而且退化程度也在加重 ,中、重度退化草地比例明显提高 ,草地退化呈发展的趋势。     

基于风云三号卫星的全球沙尘遥感方法

新一代风云三号卫星的成功发射,使面向全球沙尘发生、发展和传输的监测分析成为可能。本文利用风云三号卫星可见光红外扫描辐射计(VIRR)数据,深入阐述了沙尘遥感的物理原理,完成了多通道沙尘光谱特性分析,提出了综合沙尘遥感识别方法。结果表明:(1)近红外1.6 μm通道对沙尘存在明显的直方图峰值区,适合沙尘的动态识别;(2)中红外3.7 μm通道的反射和辐射融合特性,可以明显地区分沙尘与其他景观物;(3)红外分裂窗通道对干燥沙尘有不同的吸收衰减,这个差异对于弱沙尘的识别有重要意义。同时,本文给出了基于1.6 μm通道e指数和红外分裂窗通道比值指数的沙尘强度指数计算方法,可以定量地获得全球沙尘的强度分布。本文给出的全球4大沙尘暴多发区同一天出现沙尘天气的实例,体现了风云三号卫星极强的全球观测能力。     

Unplanned urban growth: land use/land cover change in the Guwahati Metropolitan Area,India

Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km² in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km² at an annual rate of 2.2 km². Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies.     

Assessment of the importance of moderate spatial resolution cloud climatology data in solar radiation modeling

Improving solar radiation models is critical for supporting the increase in solar energy usage and modeling ecosystem dynamics. However, coarse spatial resolutions of solar radiation models overlook the impacts resulting from spatial variability of clouds at meso- and micro-scales. To address this problem, Moderate Resolution Imaging Spectroradiometer (MODIS) cloud climatology developed by the National Severe Storms Laboratory was used to relate cloudiness to surface solar radiation observations. We developed a linear regression model between the surface solar radiation and MODIS cloud climatology and used the model to estimate average radiation across Oklahoma. Furthermore, the study compared the average error and coefficient of determination to measured ground radiation. Error analysis of the regression model showed that the differences between observed radiation and estimated radiation were spatially autocorrelated for the Aqua MODIS satellite scan. This suggests cloudiness alone is not sufficient to predict surface solar radiation. This study found that simple cloud datasets alone can account for approximately 50% of the variation in observed solar radiation at 250-m spatial resolution, but additional datasets such as optical depth, elevation, and slope are needed to accurately explain spatial distributions of incoming shortwave radiation.     

GRAPES-SDM沙尘模式预报与卫星遥感监测结果对比

GRAPES-SDM沙尘模式和卫星遥感监测是目前沙尘暴监测预报业务中重要的工具.本文使用天气学检验方法,对中国气象局兰州干旱气象研究所目前使用的GRAPES-SDM沙尘模式2012年春季沙尘天气预报情况以及FY-2D卫星遥感产品沙尘指数IDDI的监测效果进行检验评估.结果表明:沙尘模式在西北沙尘暴预报业务中具有很好的预报参考价值,卫星遥感沙尘指数也具有较好的监测效果,但两者均存在一定的问题.沙尘模式对大范围沙尘暴过程有较好的预报能力,但对沙尘强度预报偏强;卫星遥感沙尘指数虽然不能定性地表示沙尘强度,但是在一定程度上能够反映沙尘强度的变化,不过反映沙尘强度的数值及其分布区间还有待于进一步完善.卫星遥感在南疆盆地常会将大片深厚的沙尘气溶胶区域误判为云区,造成对沙尘天气特别是沙尘暴天气未能识别的现象,另外IDDI指数不能用于夜间沙尘监测.     

MODIS卫星影像显示的2001-2017年中国荒漠化年度状况

年度监测是及时掌握荒漠化动态的有效方法。以MODIS卫星影像为数据源,依据荒漠化土地特征和荒漠化遥感监测指标选取原则,选取了能够基于中低分辨率MODIS卫星数据反演的4个遥感监测指标,将原国家林业局第三次荒漠化监测结果与MODIS反演的4个遥感监测指标的栅格图进行叠加,参照各监测指标在不同荒漠化程度等级下的像元值,得到各指标荒漠化程度判别值。根据原国家林业局荒漠化监测气候分区规定,基于各监测指标判别值,应用决策树分类方法,实现了中国不同气候区域2001-2017年的荒漠化状况年度监测。以2009年原国家林业局第四次中国荒漠化土地监测结果与本文年度监测结果对比,吻合度达92.62%。