| China is one of the most rapidly process of urbanization in the developing world,the city’s heat island effect is getting more and more severe over the years, because ofthe concentration of people in the cities, the developed industrial, traffic congestion,severe air pollution and the iconic buildings are most built by gravel and concrete,which have a lower heat capacity and a higher rate of heat transfer and with the additionof the built architectures have some effects onthe wind to stop or decrease it. As animportant part of the ecological and environmental functions, urban water becomes anindispensable part. It’s known as temperature adjuster and humidifier exhibits greatsuperiority in solving the thermal environment.The Three Gorges reservoir is a huge manual lake, which formed after thecompletion of Three Gorges hydropower station. It locates in the upriver of YangtseRiver and extends across Yangtse River for many kilometers from Yichang (HubeiProvince) up to Jiangjin (Chongqing Municipality). In October2010, the three gorgesreservoir reached the design level of175meters and became a big reservoir witha capacity of39.3billion cubic meters and a total area of1084square km. The threegorges reservoir has a very broad water basin and a plenty of space to spare. Thechanged air mixes with the main air of the land, so as to affect the thermal andpsychrometric status of the main land air. The change of reservoir levels has directinfluence on the changes of the flow condition and velocity of the water, so as to changethe thickness of the heat boundary layers and the mass transfer boundary layers and theheat and moisture transfer in the interface of “water—air”, which eventually expressedon the change of the temperature and the humidity of the air over the water.This article will analysis and discuss the climatic effects and the variation featuresof climate elements of Chongqing in recent years. Based on the statistics and analysis ofthe meteorological data of Chongqing during1961-2010, this article got these changingtrends of average temperature, relative humidity, rainfall and sunlight-time from year toyear and conducted a further analysis of their exploration to find the change rulesof Chongqing micro climate in the decades. The analysis results show that theyear-round average temperature of Chongqing decreased at first and then increased from1961to2010. The rate of increase in average temperature up to0.1℃/10a duringthe50years, which is more than0.074℃/10a in year-round average temperature,especially the rate of increase in average temperature up to0.39℃/10a from1982to2010. The average temperature of Chongqing increased at first and then decreased sincethe implement of the Three Gorges Dam project. The Three Gorges Reservoir from66meters to135meters water level in June,2003and the relative humidity and rain ofChongqing were obviously changed in this year.This paper uses conventional Mobile measurement, as well as gives anothermethod and this method requires less limiting condition but very persuasive. Themethod is that we directly took the interface of “water—air” as the object of study tostudy the Moisture and heat transfer between water and air to solve the question thatwater is heating effects or cooling effect or both heating and cooling effect for the air. Inorder to study how Three Gorges reservoir is impacting the climate characters ofsurrounding environment, Yangtze River and Jialing River as well as tributaries inChongqing were chosen as subjects in this article. The mechanism of effect wasdiscussed and analyzed by the academic analyzing and test. The analysis results showthat water has a certain influence to the distribution of temperature and humidity alongthe river and this effect can be characterized by temperature raising andhumidity reducing,at this point the direction of heat transfer away from the water andthe direction of moisture transfer points the water,or by temperature reducing andhumidity raising,at this point the direction of heat transfer points the water and thedirection of moisture transfer away from the water. The effect of water on the verticalplane of the temperature and humidity is significant, within the range of500~1000mand the temperature change rate is0.03~0.58℃/100m and the relative humidity changerate is0.26~2.5%/100m, within this significant scope; The influence of water on thedistribution of temperature and humidity is relatively strong near the water, and theinfluence is relatively less far from the water but the influence of otherstable factors such as city underlying surface is strong;Compared with concreteand soil underlying surface, water has strong regulatory role in temperature to make itstemperature fluctuations not so much. During the seven test in June to August, the watertemperature fluctuates from0.6to1.6℃, and theconcretetemperature fluctuatesfrom5.5to9.8℃,the soil temperature fluctuates from10.6to27.8℃；Compared with air, water always shows acool effect andthe effect intensity ranges from32186to38109KJ/m· d; Compared with concrete underlying surface, water will show astronger heat effect in the rainy weather and can significantly reduce the heating effectof the thermal environmentin other weather conditions of the test. Compared withconcrete, the thermal effect of water can reduce by1125to4848KJ/m· dandCompared with soil, the thermal effectcan reduce by1064to3104KJ/m· d. |
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