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Displaying 1285 - 1296 of 1963

Patterns and causes of land change: Empirical results and conceptual considerations derived from a case study in the Swabian Alb, Germany

Journal Articles & Books
Décembre, 2013
Allemagne

Land-use and land-cover change profoundly affect human well-being and, therefore, have become a major topic for society. A thorough understanding of past and present processes transforming landscapes is essential for guiding future developments toward the sustained provision of the ecosystem services humans critically depend upon. Drawing on the driving forces and resilience frameworks, we identify possible variables and patterns of land change, connecting them to empirical findings in three case study areas in the Swabian Alb region, southwestern Germany.

Assessing the impact of urbanization on net primary productivity using multi-scale remote sensing data: a case study of Xuzhou, China

Journal Articles & Books
Décembre, 2015
Chine

An improved Carnegie Ames Stanford Approach (CASA) model based on two kinds of remote sensing (RS) data, Landsat Enhanced Thematic Mapper Plus (ETM +) and Moderate Resolution Imaging Spectro-radiometer (MODIS), and climate variables were applied to estimate the Net Primary Productivity (NPP) of Xuzhou in June of each year from 2001 to 2010. The NPP of the study area decreased as the spatial scale increased. The average NPP of terrestrial vegetation in Xuzhou showed a decreasing trend in recent years, likely due to changes in climate and environment.

Vegetation productivity trends in response to urban dynamics

Journal Articles & Books
Décembre, 2016
Argentine

Urbanization is a global phenomenon with still unknown consequences for vegetation dynamics of urban ecosystems, especially in subtropical areas of developing countries. In this paper we analyze the vegetation productivity trend associated to urban densification and urban expansion during the last decade, in twelve cities of northern Argentina. We used time series analysis of MODIS-NDVI images to reconstruct the phenological patterns to retrieve a productivity trend under three spatial classes of urban dynamics: (1) urban, (2) expansion and (3) periphery.

Modifications in vegetation cover and surface albedo during rapid urbanization: a case study from South China

Journal Articles & Books
Décembre, 2014

The green vegetation fraction (GVF) and surface albedo are important land surface parameters often used for validation of climate and land surface models that are influenced largely by environmental gradients and human activities. In this study, fine resolution GVF and albedo values derived from Landsat Thematic Mapper/Enhanced Thematic Mapper Plus images from 1990 to 2000 were used to examine the relationship of both GVF and albedo values to the spatial gradients of parameters related to dramatic urbanization in the Greater Guangzhou metropolitan area, Guangdong Province, in South China.

Watershed management in an urban setting: process, scale and administration

Journal Articles & Books
Décembre, 2012
Australie

Efforts in post-industrial countries to refine environment and planning administration in the face of unprecedented urban growth have important implications for ecological systems and human quality of life. This paper uses the case of an urban riparian corridor in South East Queensland, Australia to contribute to understandings of interactions between land use planning processes, watershed management initiatives and broader administrative structures in urban and rapidly urbanising settings. In particular it examines the understudied application of watershed management to an urban setting.

Carbon Storage by Urban Soils in the United States

Journal Articles & Books
Décembre, 2006
Hong Kong
États-Unis d'Amérique

We used data available from the literature and measurements from Baltimore, Maryland, to (i) assess inter-city variability of soil organic carbon (SOC) pools (1-m depth) of six cities (Atlanta, Baltimore, Boston, Chicago, Oakland, and Syracuse); (ii) calculate the net effect of urban land-use conversion on SOC pools for the same cities; (iii) use the National Land Cover Database to extrapolate total SOC pools for each of the lower 48 U.S. states; and (iv) compare these totals with aboveground totals of carbon storage by trees.

Simulation of soil carbon changes due to land use change in urban areas in China

Journal Articles & Books
Décembre, 2013
Chine

Land use change can have a strong impact on soil carbon dynamics and carbon stocks in urban areas. Due to rapid urbanization, large areas of land have been paved, and other areas have undergone rapid land use change. Evaluation of the impact of urbanization on carbon dynamics and carbon stock (30 cm) has become an issue of urgent concern. The soil carbon dynamics, due to rapid land use change in Tianjin Binhai New Area of China, have been simulated in this paper using the RothC model.

Efficient segmentation of urban areas by the VIBI

Journal Articles & Books
Décembre, 2012

Urban populations are expanding rapidly and so are cities. Remote sensing offers a convenient means of monitoring this expansion as it covers a period of 40 years in the case of the LANDSAT satellite. In some parts of the globe, this is probably the only viable means of monitoring due to the lack of other types of data. In order to monitor expansion, first, urban land has to be separated from other land-cover types.

Urbanization effects on spatial-temporal differentiation of tree communities in high-density residential areas

Journal Articles & Books
Décembre, 2015
Hong Kong

The changing mode of urban development through time can bring a varied landscape mosaic accompanied by spatial-temporal differentiation of urban vegetation. Hong Kong as an ultra-compact city generates intense interactions between trees and urban fabric to highlight urbanization effects on tree communities. The study areas cover public housing estates which accommodate about half of the 7.26 million population. Thirteen site factors related to estate, landform and habitat traits were measured or computed as surrogate urbanization effects.

Comparison of Different Mapping Techniques for Classifying Hyperspectral Data

Journal Articles & Books
Décembre, 2012

Hyperion is a space borne sensor which provides powerful tool in discriminating land cover features including urban area and in preparation of urban maps. It gives hyperspectral images in 242 bands within 400 nm to 2,500 nm wavelength range with 10 nm band-width. The Hyperion image in raw form is badly affected with several atmospheric effects which cause haziness. In this study hyperspectral image is atmospherically corrected by using FLAASH model of ENVI.

Classification and quantification of green in the expanding urban and semi-urban complex: Application of detailed field data and IKONOS-imagery

Journal Articles & Books
Décembre, 2011
Belgique

Urban land cover is expanding rapidly worldwide. This major phenomenon is often accompanied by an expansion of a green component. Urban green can itself be considered as a most important but often ignored land cover category. With this study we investigate how IKONOS data can be used more exhaustively for the detection and more importantly the quantification of urban green, compared to state-of-the art investigations.