Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 55.
  1. Library Resource
    Synthesis of agricultural land system change in China over the past 40 years
    Publication évaluée par des pairs
    février, 2019
    Chine

    In summary, China presents a particularly intriguing case for the study of land system dynamics with its spatial patterns of cropland and crops, crop structure and diversity, land transfer and consolidation, and land use intensity changes against the backdrop of its rapid socio-economic transformation, globalization, and environmental challenges. Moreover, after 40 years since the commencement of China’s Economic Reform and the de-collectivization of agriculture, it is a good time to review and reflect how China’s agricultural land systems have been transformed.

  2. Library Resource
    Articles et Livres
    septembre, 2013
    Chine, Asie orientale

    Implementation of land management policies influences land use and hence
    causes environmental change. Taking the Ordos rangelands in China as a case
    study, this paper explores the potential of remote sensing to assess in dryland
    areas the impacts of policies on the environment. Thirteen Landsat images of the
    period 1978 2010 were acquired and those corresponding to the starting dates of
    implementation of different policies were selected for land-cover change analysis;
    others were used to check the detected change and track the normalized

  3. Library Resource
    Articles et Livres
    décembre, 2011
    Chine

    The Geoscience Laser Altimeter System (GLAS) instrument onboard the Ice, Cloud and land Elevation Satellite (ICESat) provides elevation data with very high accuracy which can be used as ground data to evaluate the vertical accuracy of an existing Digital Elevation Model (DEM). In this article, we examine the differences between ICESat elevation data (from the 1064 nm channel) and Shuttle Radar Topography Mission (SRTM) DEM of 3 arcsec resolution (90 m) and map-based DEMs in the Qinghai-Tibet (or Tibetan) Plateau, China.

  4. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    Accurate and timely land cover change detection at regional and global scales is necessary for both natural resource management and global environmental change studies. Satellite remote sensing has been widely used in land cover change detection over the past three decades. The variety of satellites which have been launched for Earth Observation (EO) and the large volume of remotely sensed data archives acquired by different sensors provide a unique opportunity for land cover change detection.

  5. Library Resource
    Articles et Livres
    décembre, 2015
    Chine

    The Shangri-La County of the Yunnan Province, SW China, is an economically and ecologically important area. This is especially true for Jiantang that is famous for the Napahai, Bitahai and Shudu Lake wetlands. However, continuing development has threatened the wetland ecosystems and the associated biodiversity in these areas. To better document such changes in land use and their effect on the ecosystem, land use was mapped using a time series of satellite images acquired in 1974, 1993, 2000 and 2012. The results of this survey suggest that forest cover first decreased and then increased.

  6. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    The Loess Plateau suffers the most serious soil erosion in China. Sloping cultivated land is one of the most common land types in the region, and it leads to severe soil erosion. Analyses based on fine resolution satellite imagery can play a key role in the surveying of sloping farmland. In this article, a combination of remote-sensing (RS) and geographical information system (GIS) techniques under the hierarchical classification framework is used to investigate the sloping cultivated land in the Xi–He ecological engineering demonstration region of the Loess Plateau.

  7. Library Resource
    Articles et Livres
    décembre, 2011
    Chine

    Land managements and agricultural practices in China changed significantly during the past 25 years. Differences in soil fertility parameters between 1981 and 2006 in Jingzhou County, China were investigated, with the changes of land management and agricultural practices. The results showed that, from 1981 to 2006, soil pH and organic matter decreased by 3.35% and 32.2%, while total nitrogen (TN), available N (AN), available phosphorus (AP), and available potassium (AK) increased by 0.4 g kg⁻¹, 21 mg kg⁻¹, 8 mg kg⁻1, and 32 mg kg⁻¹, respectively.

  8. Library Resource
    Articles et Livres
    décembre, 2012
    Japon

    We analysed Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data on the areas damaged by the Iwate–Miyagi Nairiku earthquake that struck Japan in 2008. The observations before and after the earthquake have been carried out in the full polarimetric mode. We observed the dominance of surface scattering of the three-component scattering model in the landslide areas and identified 11 of the 13 landslide areas. However, we also detected vacant pieces of land, pastures and other land bodies.

  9. Library Resource
    Articles et Livres
    décembre, 2011
    Chine

    Grassland degradation not only results in soil degradation and severe decreases in land productivity, but also can promote the emission of soil carbon and nitrogen compounds as greenhouse gases into the atmosphere. The primary objective of this study was to characterize the impact of grassland degradation on carbon and nitrogen budgets in Inner Mongolia, China. We investigated the changes of total carbon, organic carbon, inorganic carbon and total nitrogen that occur in a grassland ecosystem (including vegetation and top 30 cm soil layer) in the course of grassland degradation.

  10. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    Time series of vegetation index (VI) information derived from remote sensing is important for land-cover change detection. Although traditional change vector analysis (TCVA) is an effective method for extracting land-cover change information from a time series of VI data, it has the disadvantage of being too sensitive to temporal fluctuations in VI values. The method tends to overestimate the changes and confuse the actual land-cover conversion with the land covers that have not been converted but experience significant VI changes.

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