| The area around the Taihu lake is one of developed areas in China. Suzhou, which represented as a typical urban city in this area, since 1990’s, in which all kinds of regional climatic effect of problems brought by the fast urbanization have appeared under the background of global climate change and the rapid development of urbanization. Especially the turbidity climatic effect in Suzhou is outstanding.Based on the data of the daily mean temperature and daily precipitation of 9 meteorological stations in the area around the Taihu Lake during the period of 1971 to 2010, and the statistical yearbook database of 1985 to 2010 in Suzhou. in this paper, the methods of linear regression, EOF analysis, Morlet wavelets analysis and Mann-Kendall Test were used to analyze the spatial and temporal pattern and characteristics of climate changes both in Suzhou and around the whole area of Taihu Lake. Besides, the method of principal component analysis, the Pearson and Spearman correlation analysis were used to construct the comprehensive urbanizational index and analyze the tendency of urbanization in Suzhou during the recent 25 years.Combined with the data of haze days, sunshine duration, precipitation, the appropriate total and scatter radiation empirical formual were selected for calculating of the turbidity factor(D/S) in Suzhou and analysis of its’tendency. Meanwhile, with the method of correlation analysis, the correlation among the climatic elements, unbanization and turbidity factor(D/S) was analyzed.The results showed as follows:(1) The temperature and the precipitation increased significantly in the area around the Taihu lake during the 1971 to 2010. Annual mean temperature fluctuated significantly with an interval of 12 years, and fluctuated with an interval of 35 years in the large scale of the whole area around the Taihu Lake; The annual precipitation in the area fluctuated significantly with an interval of 25 years, and fluctuated with the intervals of 5 years and 30 or 35 years. Besides, there was a transilience, which appeared in the year between 1992 and 1993, from low temperature to high temperature, and a transilience of precipitation, which appeared in the year between 1972 and 1993 during the 40 years.(2) The temperature and the precipitation increased significantly in the area of Suzhou, too. Annual mean temperature fluctuated significantly with the intervals of 24 years or 25 years, and fluctuated with the intervals of 6 years or 35 years; The annual precipitation in Suzhou fluctuated significantly with the intervals of 4 years,10 years and 35 years. Besides, there was a transilience, which appeared in the year of 1992, from low temperature to high temperature, and a transilience of precipitation, which appeared before the year of 1980, during the 40 years.(3) The urbanization in Suzhou have been developing at a particularly high rate since the 1990s. With a short period of decreasing of afforestation coverage in this city, it increased during the recent 25 years overall. There was a significant correlation between the comprehensive urbanization index and the annual mean temperature in Suzhou, with the correlation coefficient of 0.679, which has passed the significance test of 0.01, and a significant correlation between the comprehensive urbanization index and the annual precipitation in the area of Taihu lake, with the correlation coefficient of 0.675, which has also passed the significance test of 0.01.(4) The scattered radiation in Suzhou was obviously increased during the year from 1992 to 2000 at a rate of 192.2MJ·m-2/10a, while the direct radiation was decreased during the same time, at a rate of 139.8MJ·m-2/10a. The turbidity factor(D/S) in Suzhou slowly increased at a rate of 0.17MJ·m-2/10a. The turbidity factor(D/S) increased significantly during the years from 1999 to 2000, following with the reduction of sunshine duration and atmospheric visibility. The rainfall increased and the low cloud covered in a wider range in the city than the rural regions. Especially the haze days increased dramatically during this period.(5) There was a significant correlation between the turbidity factor and the number of rainy days and the annual mean precipitation in Suzhou, with the correlation coefficient of 0.488 for the former, and the correlation coefficient of 0.588 for the latter, both have passed the significance test. Meanwhile, there also was a significant correlation between the turbidity island effect and urbanization, with the correlation coefficient of 0.636, which also passed the significance test of 0.05 during the period of 1993 to 2002. |
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