The Impact of Urbanization on Urban Dew Condensation
It is of great significance to study the urbanization process by comparing the urban dew with country dew. In view of the current urban dew less comparative study carried out, this research is necessary. The experiments were carried out in the urban area of Guangzhou and its suburban areas. The dew collection was carried out by cloth-plate method. The observation time was August -October 2005 and January, April and July 2006 respectively. The results showed that the frequency of dew in different seasons was coincident with that in suburbs, ie, autumn>winter>summer>spring, especially in the autumn (73.3% in urban area, 80.6% in country). In addition to the spring mean dew amounts measured in urban concrete condensation slightly higher than those measured in Conghua country (0.016 mm), the dew amounts of different underlying surface in city were all lower than those in country. In the spring, the average dew condensation volume measured from lawn and concrete in the urban area and the country had no significant difference, and the average dew condensation amount in the other seasons was significant or extremely significant in urban and suburbs. Such as in autumn, the average amount of dew condensation on lawn, shrub and concrete was 6.4 times, 10.4 times and 4.5 times higher than that in urban area, respectively, and arrived at 0.070, 0.099 and 0.039 mm. In the summer, autumn and winter, the maximum dew condensation volume on the suburb surface is higher than that in the urban area. Such as the autumn dew in country, condensed on lawn, shrub and concrete, was 4.6 times, 4.1 times, 5.0 times of that in city, respectively, and arrived at 0.224, 0.178 and 0.139 mm. Urbanization changed the seasonal variation of dew condensation on the underlying surface, and the seasonal variation of dew in the urban area was different from that in the suburbs. The dew water samples in the urban area were 100%acidified, and serious than that in country (43%). The minimum and average pH values of the dew samples in the urban areas were all smaller than those in the country, and the maximum dew pH in the urban areas was smaller than those in country about 1.5. The results suggested that urbanization did not significantly affect the frequency of dew in city and country, but influenced the amount of dew condensation, seasonal variation of dew condensation on the underlying surface and its acidity.
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NSTL
万方数据
维普
