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There are 2, 238 content items of different types and languages related to couverture du sol on the Land Portal.

couverture du sol

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Validation of MODIS, MISR, OMI, and CALIPSO aerosol optical thickness using ground-based sunphotometers in Hong Kong

Journal Articles & Books
Décembre, 2013
Hong Kong

Aerosol observations are essential for understanding the Earth's radiation budget and the complexities of climate change, as they are involved in the backscattering of solar radiation and the formation of cloud condensation nuclei. In Hong Kong, the most direct effect is on air quality. Atmospheric haze caused by the emission of aerosols from industrial and vehicular sources creates visibility lower than 8 km for approximately 20% of the time, having risen at 6% per decade since 1980, but regional emissions are at least as influential as local ones.

Policy impacts on regulating ecosystem services: looking at the implications of 60 years of landscape change on soil erosion prevention in a Mediterranean silvo-pastoral system

Journal Articles & Books
Décembre, 2016
Portugal

CONTEXT: Policy decisions form a major driver of land use change, with important implications for socially and environmentally susceptible regions. It is well known that there can be major unintended consequences, especially where policies are not tailored to regionally specific contexts. OBJECTIVES: In this paper we assess the implications of 60 years of agricultural policies on soil erosion prevention (SEP) by vegetation, an essential regulating ecosystem service in Mediterranean Europe.

Pollen‐based quantitative reconstructions of Holocene regional vegetation cover (plant‐functional types and land‐cover types) in Europe suitable for climate modelling

Journal Articles & Books
Décembre, 2015
Irlande
Europe

We present quantitative reconstructions of regional vegetation cover in north‐western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling.

Simulation of the interannual variations of biogenic emissions of volatile organic compounds in China: Impacts on tropospheric ozone and secondary organic aerosol

Journal Articles & Books
Décembre, 2012
Chine

We use the MEGAN (Model of emissions of Gases and Aerosols from Nature) module embedded within the global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) to simulate the interannual variations in biogenic volatile organic compound (BVOC) emissions and concentrations of ozone and secondary organic aerosols (SOA) in China over years 2001–2006.

Relevance assessment of full-waveform lidar data for urban area classification

Journal Articles & Books
Décembre, 2011

Full-waveform lidar data are increasingly being available. Morphological features can be retrieved from the echoes composing the waveforms, and are now extensively used for a large variety of land-cover mapping issues. However, the genuine contribution of these features with respect to those computed from standard discrete return lidar systems has been barely theoretically investigated. This paper therefore aims to study the potential of full-waveform data through the automatic classification of urban areas in building, ground, and vegetation points.

change vector analysis technique for monitoring land cover changes in Copsa Mica, Romania, in the period 1985–2011

Journal Articles & Books
Décembre, 2014
Roumanie
Europe

During the communist regime, Romania’s planned economy focused exclusively on production neglecting the environment protection. The lack of less polluting production technologies and of environmental protection measures led to excessive pollution in certain industrialized areas. This is the case of the town of Copsa Mica in Sibiu County, which in 1987 was considered one of the most polluted towns in Europe.

Using a sub-pixel mapping model to improve the accuracy of landscape pattern indices

Journal Articles & Books
Décembre, 2011

The assessment of landscape spatial patterns is a key issue in landscape management. Landscape pattern indices (LPIs) are tools appropriate for analyzing landscape spatial patterns. LPIs are often derived from raster land cover maps that are extracted from remotely sensed data through hard classification. However, pixel-based hard classification methods suffer from the mixed pixel problem (in which pixels contain more than one land cover class), making for inaccurate classification maps and LPIs.

Upscaling of evapotranspiration fluxes from instantaneous to daytime scales for thermal remote sensing applications

Journal Articles & Books
Décembre, 2014

Four upscaling methods for estimating daytime actual evapotranspiration (ET) from single time-of-day snapshots, as commonly retrieved using remote sensing, were compared. These methods assume self-preservation of the ratio between ET and a given reference variable over the daytime hours. The analysis was performed using eddy covariance data collected at 12 AmeriFlux towers, sampling a fairly wide range in climatic and land cover conditions. The choice of energy budget closure method significantly impacted performance using different scaling methodologies.

Evaluation of Bagging, Boosting, and Random Forests for Land-Cover Classification in Cape Cod, Massachusetts, USA

Journal Articles & Books
Décembre, 2012
États-Unis d'Amérique

The iterative and convergent nature of ensemble learning algorithms provides potential for improving classification of complex landscapes. This study performs land-cover classification in a heterogeneous Massachusetts landscape by comparing three ensemble learning techniques (bagging, boosting, and random forests) and a non-ensemble learning algorithm (classification trees) using multiple criteria related to algorithm and training data characteristics.

Land cover changes on the coastal zone of Candarli Bay, Turkey using remotely sensed data

Journal Articles & Books
Décembre, 2009
Turquie

Land cover of the Earth is changing dramatically because of human activities. Information about changes is useful for management of natural resources. Rapid land cover changes have taken place in many coastal areas of Turkey over the last two decades due to urbanization and land degradation. In this paper, land cover change dynamics were investigated by the combined use of satellite remote sensing and geographical information systems. The main objective of the study was to determine land-cover transition rates among land cover types in coastal areas of Turkey.

Using Advanced Land Imager (ALI) and Landsat Thematic Mapper (TM) for the Detection of the Invasive Shrub Lonicera maackii in Southwestern Ohio Forests

Journal Articles & Books
Décembre, 2012

We tested how accurately image data from the Advanced Land Imager (ALI) sensor vs. the Landsat Thematic Mapper (TM) predict the land cover of Lonicera maackii in the forest understory, taking advantage of this invasive shrub's extended leaf retention in the fall when the canopy is leafless. Percent cover of L. maackii in 20 woodlots in southwestern Ohio was regressed on values for spectral vegetation indices (SVIs) derived for each image. The land cover of L. maackii was best explained by the Simple Ratio (SR) using TM data (R ² = 0.537). The regression results for SVIs from TM vs.