外文翻译--城市环境下的绿色屋顶-环境工程(编辑修改稿)

外文翻译--城市环境下的绿色屋顶-环境工程(编辑修改稿)内容摘要：

s a good chance of achieving success of grassy rooftops if domestic, uncultivated, heat and dryness tolerant grasses are used. Up through the end of the 1970’s, in Europe, the concept of green roof was understood to be the so called intensive green roof garden. During the last ten years, however, as a result of a change in point of view, the extensive roofs have bee widespread. These roofs have given way to a more ecological city planning concept, especially in the design of extensive industrial buildings. Observation of intensive roofs has shown that the direct utilization of roof gardens is negligible. 2 CONSTRUCTIONS Cost cutting requirements as well as lighter roof structures have been motivating forces behind the move toward the use of the thin layered, more economically viable extensive green roof solution. The simpler construction and maintenance options have placed the extensive solution in a more favorable position. The intensive roof gardens developed well where plenty of water and fertilizer were available, but left alone, they didn’t last long. With extensive roof gardens the dry grasses and steppetype vegetation gained ground as well as the naturally sprouting and enduring plants. It has been observed that the naturally 8 sprouting vegetation is able to regenerate annually without care. The green roof solutions mon in Northern Europe utilized a thicker layer of vegetation. However, much more precipitation is characteristic in these areas then in Hungary, and there is a higher overall level of humidity as well. In Central Europe the weather conditions for green roofs are somewhat less favorable. The climate is drier and there is a greater fluctuation in temperature. Therefore, in the case of extensive green roofs, the moisturebalance property of the roofs has to be carefully planned. In these cases the different drainage layers play a significant role (see figure 1) as well as the degree of the slope and the usage of drainage method. Figure 1: 9 Figure 1 There is a good chance of the survival of the so called simpler intensive green roof solution, which, with some care, can be a viable solution even in Central Europe. In this category, under care, we mean the necessary water supply, periodical addition of nutrients, cutting and mowing. Based on international green roofing practices, as well as domestic green roofing experiments, it can be determined that currently green roofs are realistic alternatives for the replacement of developed former green areas. The great number of existing flat roofs and 10 those under construction can be converted into ecologically functioning surfaces. Grassy roofs and roof gardens provide an advantage over insulated roofs and roof terraces. One important advantage is the pleasant, tranquil view. Green surfaces are especially desirable for lessening the rigid, boxtype effect of buildings. In the 1920’s Le Corbusier, in his acclaimed thesis on modern architecture, already pointed out the potentials for expanding the active living areas with roof gardens. Nowadays, the demand for the development of a healthier urban environment is getting more and more urgent since air pollution is nearing the limits of tolerance. The evaporation and oxygen producing effect of the planted vegetation on the roofs of buildings can contribute to the improvement of the microclimate. Evaporation controls the air temperature and humidity, the air being cleaner with the increased production of oxygen. Dust removal。