Page - 320 - in Book of Full Papers - Symposium Hydro Engineering

Taking everything into account,air temperature and moisture are affected by heat and mass transfer between the air boundary layer and the reservoir water surface,especially during the water storage period the contact area.Based on the above theory analysis,research on climate changes firstly collected related annual and monthly climate dataand calculated correlation between climatic elements and time sequences to summarize climate tendency at different times.In order to test the significance of important parameters, the t testing method was taken to verify the average difference of climate elements, pre and post reservoir water storage,and the F testing method was for evaluating the influence of climate change in the above process. 4. THEORY ANALYSIS Climate changes were analyzed in representative counties around the reservoir. A County was selected for climate trend analysis close to the reservoir, as well as the dam (about 3km from the weather station),B County for the reservoir upstream(about 7km from the weather station). Additionally,A County was also analyzed for the effects of water storage,since it is largely affected by the reservoir.Air temperature, humidity and precipitation were studied comprehensively concerning climate changes, from 1st January 2011 to 31stDecember 2016. To distinguish the trends of climate change, periods of air temperature and air humidity were analysed as follows:1st December to 28th February,1st March to 31stMay,1st June to 31stAugust, 1st September to 30th November, being winter,spring,summer and autumn respectively, and the main flood season was taken as1stMay to 30th September. 4.1. CLIMATE CHANGES IN A COUNTY As shown in Figure 4, the air temperature of A County displays some differences before and after water storage, especially in the winter and summer seasons. Compared to the air temperature before water storage, the air temperature after water storage has little temperature difference, which is concentrated between8.4 ℃ and25.2 ℃.The maximum temperature difference is 7℃ higher thanthe previous record in winter. What's more, air temperature is essentially the same in the spring and autumn seasons. Due to the huge specific heat capacity of water,large temperature differences result in summer and winter after water storage.Reservoir water releases heat to the air,causing higher air temperatures than beforeand vice versa in summer.Air temperature keeps consistent in spring and autumn, since there are no large temperature changes and little heat transfer between air and water.Therefore,there exists a more suitable environmental for people to live and plants to grow. 320