Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 160.
  1. Library Resource
    Articles et Livres
    décembre, 2013
    Japon

    This study aimed at clarifying the relationship between the dynamics of land use/land cover (LULC) changes and decline in the groundwater levels, and specifying an LULC category strongly affecting such decline in a Quaternary sedimentary basin. Groundwater level data recorded at 26 observation wells for a 14-year period in the Kumamoto Plain, central Kyushu, southwest Japan, were used for the analysis. The general trends of LULC were detected by a satellite image classification technique and surface spline method, which highlighted the decreases in groundwater-recharge materials.

  2. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    Karst terrains are generally regarded as a fragile and vulnerable environment. China’s karst is mainly developed in pre-Triassic, old-phase, hard, compact carbonate rock. The lack of soil cover in bare karst land can enhance desertification. Its underground drainage system can aggravate both drought and flooding problems; the interconnected surface and subsurface conditions allow for easy contamination by pollutants.

  3. Library Resource
    Articles et Livres
    décembre, 2015
    Chine

    Groundwater vulnerability assessment is an important method for groundwater pollution risk assessment. However, vulnerability assessment results rarely consider groundwater pollution concentration. Few quantitative studies consider groundwater pollutant concentration in different hydrogeological conditions. HYDRUS-1D software can simulate different concentrations of pollutants reaching the shallow aquifer under some vadose zone conditions.

  4. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    Agricultural nonpoint source (NPS) pollution at the Three Gorges reservoir area in China has been increasingly recognized as a threat to aquatic environment in recent years due to the serious eutrophication problem. Adsorbed NPS pollution is one of the major forms of NPS pollution in mountainous regions, the essential of the adsorbed NPS pollution is soil loss. Thus, simple, highly sensitive and continuous methods are required to simulate and quantify sediments yield at watershed scales.

  5. Library Resource
    Articles et Livres
    décembre, 2013
    Chine

    Over the past decades, the vast limestone mountain areas in southwestern China have suffered greatly from karst rocky desertification (KRD), which is a unique type of desertification caused by irrational land-use practices and has drawn increasing attention of international academic community. Characterizing soil erosion in this region is the key to understanding the escalating KRD problem and finding solution to it. The authors applied leveling method to study soil erosion process in the Huajiang Karst Canyon area between 1999 and 2003, and tried to relate it to KRD expansion.

  6. Library Resource
    Articles et Livres
    décembre, 2005
    République de Corée

    A combined approach of remote sensing (RS) and geographical information systems (GIS) was used in this study to identify the impact on urban surface radiant temperature (SRT) of urban green-space change. Urban SRT increases as green-space area is converted into non-green-space area. Also, well preserved green space and newly connected green space contribute to a decrease of the SRT. Seoul Metropolitan area is rapidly expanding. Existing urban SRT studies have, however, mainly been conducted for Seoul City.

  7. Library Resource
    Articles et Livres
    décembre, 2014
    Chine

    China launched the “Returning Grazing Lands to Grasslands” project about a decade ago to restore severely degraded grasslands. Grassland grazing exclusion was one of the experimental approaches for achieving the grand goal. Here, we evaluate the long-term regional ecological effects of grassland grazing exclusion in the Xilingol region of Inner Mongolia, China. The dynamics of grassland communities over 8 years (2004–2011) were continuously monitored at 11 research sites dominated by temperate steppe ecosystems.

  8. Library Resource
    Articles et Livres
    décembre, 2016
    Chine

    There are widespread concerns about urban sprawl in China. In response, modeling and assessing urban expansion and subsequent land use and land cover (LULC) changes have become important approaches to support decisions about appropriate development and land resource use. Guangzhou, a major metropolitan city in South China, has experienced rapid urbanization and great economic growth in the past few decades. This study applied a series of Landsat images to assess the urban expansion and subsequent LULC changes over 35 years, from 1979 to 2013.

  9. Library Resource
    Articles et Livres
    décembre, 2013
    Chine, Mongolie

    In order to understand the genetic diversity of wild Ussurian pears in China, chloroplast DNA (cpDNA) of 186 wild accessions from 12 populations in Inner Mongolia, Heilongjiang and Jilin Provinces and 51 Chinese and European pear cultivars including Pyrus ussuriensis, Pyrus pyrifolia, Pyrus bretschneideri, Pyrus sinkiangensis and Pyrus communis were investigated. Each accession was classified into one of three types (types A, B and C) based on two large deletions in the hypervariable regions between the accD–psaI and rps16–trnQ genes.

  10. Library Resource
    Articles et Livres
    décembre, 2015
    Chine

    Various spectral data preprocessing approaches have been used to improve endmember extraction for urban landscape decomposition, yet little is known of their comparative adequacy for impervious surface mapping. This study tested four commonly used spectral data treatment strategies for endmember derivation, including original spectra, image fusion via principal component analysis, spectral normalization, and the minimum noise fraction (MNF) transformation.

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