| The problems upon urban climate change and atmospheric brought by the urbanization have been widely concerned by all social sectors,and also were one of the important connotation of global climate change.In this paper we systematically studied the influence on local rainfall and temperation caused by Jinan urbanization development,and spatial & temporal variations of urban heat island(UHI)effect in the last 50 years through utilizing Jinan's 5 urban development index data during 1949—2013,which includes urbanization rate,total gross industrial output,paved roads area,number of operating vehicle in public transportation and completed building space,as well as the data of yearly temperature and precipitation of 6 meteorological observation stations from 1964 to 2013,and temperature data of 64 regional automatic meteorological stations from 2012 to 2014.The results are as follows:1,Based on the statistical analysis of the urban development indicators,regarding 1980 as critical point,we found that Jinan's urbanization process can be divided into 2 different development stages,among which the slow development period was from 1949 to 1980,alternatively,the fast period was from 1981 to 2013.The reason just was that it was a slower speed of Jinan's urbanized advancement from 1949 to 1979.However there was a big change since reform and opening up,whatever the road area in Jinan city,industrial gross output and building's construction area all increased by several times or even hundreds of times..2,Nearly 50 years,generally the variation of annual precipitation in Jinan showed a slightly increasing trend in volatility.The annual rainfall rising rate was up to 14.86mm/10 a,and the analysis found that the increase of annual precipitation mainly caused by the increasing rainfall in summer.It was the increased tendency of rainfall during the fast development period in all seasons.It also indicated the abrupt changes during the year of 1989 and 2002,showing the rainy and dry period of more frequent alternation features.3,The increasing trend of precipitation in urban was significantly higher than that existed in suburbs nearly 50 years.The main impact of the urban reaction on climate change was the increased heavy rain(>25mm)and storm rainfall(>50mm),especially the high rainfall intensity in urban.The heaviest annual precipitation was recorded in Jinan urban station,both in the slow and fast urban development periods,showing “urban rain island effect” obviously,which result in increasing the risk of urban waterlogging.4,In recent 50 years,the temperature in Jinan represented the warming trend.The rising ratio in annual temperature,the highest and lowest temperature was 0.230?/10 a,0.118?/10 a and 0.323?/10 a,it mainly happened in the fast urban development period,and the most significant tendency was the lowest temperature.There were obvious changes in temperature period in nearly 50 years of temperature change,among which,there is a cool period from 1964 to 1992,and a warm period from 1993 to 2013.5,The heat island intensity of Jinan showed an increasing trend.With the growth rate on heat island intensity was at 0.063?/10 a,0.023?/10 a and 0.193?/10 a accordingly caused by average temperature,the highest and lowest temperature,and the contribution rate to the urban warming was at 22.3%,16.8% and 39.9% respectively,therefore the influence of the urbanization development on the lowest temperature was the most obvious.The warming trend can be largely attributed to the impact of urbanization/urban heat island in Ji'nan during the recent 50 years.Considering the enhanced heat island intensity of Jinan from the seasonal change perspective,it was winter that the intensity increased most significantly,followed autumn,and spring and summer were the weakest.The diurnal variation of the heat island effect is weaker in the day and stronger in the night.The Quancheng square and its surrounding downtown zone was always the center of urban heat island in Jinan in different seasons.6,By establishing the relational model between the Jinan urbanization and heat island intensity,we found the impact on temperature due to Jinan urbanization applied to the cubic regression model approximately.The correlation coefficient between Jinan urban heat island intensity and integrated urban development index was significant.The main factors for the heat island intensity were industrial gross output and the number of public transit vehicles at year-end from 1964 to 1980,and gross industrial output value,paved roads area and the urbanization ratio for the year 1981 to 2013. |
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