排序方式： 共有5条查询结果，搜索用时 15 毫秒
1
1.
Studia Geophysica et Geodaetica - The ionospheric response to geomagnetic storms is usually investigated by considering the variability of the critical frequency of the F2-layer (foF2) or the total... 相似文献
2.
3.
Jan Feranec Monika Kopecka Rumiana Vatseva Anton Stoimenov Jan Otahel Juraj Betak Karol Husar 《Central European Journal of Geosciences》2009,1(1):106-119
Landscape change assessment was conducted in selected areas of Slovakia and Bulgaria in 1990–2000 using CORINE land cover (CLC) data layer analysis. Assessment of causes that led to these changes was undertaken, with an emphasis on those that determined the extensification of agriculture. The LC data were obtained under the CLC90 and I&CLC2000 projects, jointly managed by the European Environment Agency in Copenhagen, Denmark and the Joint Research Centre of the European Commission in Ispra, Italy. The CLC1990-2000-changes data layer was generated by overlaying the CLC90 and CLC2000 data layers for change in areas of a minimum 5 ha. The analysed causes of changes (driving forces) were then classified. Land cover (LC) changes characterizing urbanization processes occurred only in the Trnava and Tatras areas. Intensification of agriculture was also higher in these two areas. LC changes characterizing the extensification of agriculture were dominant in Plovdiv and Trnava. Deforestation and forestation were identified in all areas (Trnava, Tatras, Plovdiv, and Burgas). The basic reasons of these changes were related to the transformation of national economies from being centrally planned to market controlled, following the fall of socialism and before the countries joined the European Union. 相似文献
4.
5.
Yuqin Liu Jiahui Zhang Linlin Zhang Tamas Jancso Rumiana Vatseva 《International Journal of Digital Earth》2016,9(4):387-409
Urban green space forms an integral part of urban ecosystems. Quantifying urban green space is of substantial importance for urban planning and development. Considering the drawbacks of previous urban green space index models, which established either through a grid method or green distribution, and the difficulty of the validation process of earlier urban green space index models, this study exploits the advantages of multisource high-resolution remote sensing data to establish a Building Neighborhood Green Index (BNGI) model. The model which analyzes the spatial configuration of built-up areas and the vegetation is based on the building-oriented method and considers four parameters – Green Index (GI), proximity to green, building sparsity, and building height. Comparing BNGI with GI in different types of characteristic building regions, it was found that BNGI evaluates urban green space more sensitively. It was also found that high-rise low-sparsity area has a lower mean value of BNGI (0.56) as compared with that of low-rise low-sparsity neighborhood (0.62), whereas mean GI (0.24) is equal for both neighborhoods. Taking characteristics of urban building and green types into consideration, BNGI model can be effectively used in many fields such as land suitability analysis and urban planning. 相似文献
1