Temperature and Solar Radiation's Amendment of a Canyon Reservoir with Its Application

Taken the influence of a canyon reservoir surrounding terrain on meteorological factors into account, based on the previous research, the regression remainder method is used to calculate temperature including orographic influence. And a simplified algorithm is applied to calculate solar radiation on the slope land of parallel mountain ridge. Taking Ertan reservoir of Yalong River valley as example, the change regularity of temperature and solar radiation under terrain influence is studied. The river bank slope is about 30 degree, and the main trend of this reservoir is S-N. There are 8 observation stations around reservoir, providing data of annual sunlight average percentage and the temperature. According to the terrain and the trend, Ertan reservoir is divided into 8 groups including 9 points from reservoir tail to reservoir head. Suppose that the temperature is divided into four revisal components-latitude, longitude, altitude and microtopography, and the multivariate linear regression equation is applied to be fit. The equation is qualified because that the value of F is over 35, and the multiple correlation coefficients are over 0.98. The results show that the parameter b₁ has negative value in the whole year, the temperature of each month decreases with the latitude increasing, and t its value is larger in winter and spring than that in summer and autumn and its annual variation is obvious; the second parameter b₂ has positive value in the year except for May, June, September, and generally the temperature of each month increases with the longitude, and its annual amplitude is very large; the value of the last parameter b₃ keeps positive during the year, which means that the temperature of each month decreases with the altitude increasing, but its value is smaller compared with the parameter b₁ and b₂. The application results show that the test precision could reach 0.5℃ by the multivariate regression equation, and the temperature data of Yanbian weather station in the same period of time has verified the result by the equation. The prediction results of temperature in Ertan reservoir show that temperature increases along the river, and the difference of annual temperature between reservoir tail and reservoir head is 1.6℃, which is in consistent with the variation characteristics of climate. Compared with flatland, there are changes on solar radiation of Ertan reservoir due to mountain masking. Besides, different gradients exert influence on solar radiation that Ertan reservoir received. Compared with that of the non-correction annual solar radiation, the corrected is reduced by 9%, which is 15 W/m². And the change of the solar radiation is greater with the increase of slope. The temporal and spatial variations of the solar radiation in the mountain area is revealed, which is contributed by the interaction of the solar declination and geographic latitude and terrain slope. As far as the slope 20 of and 50 dagree concerned, the annual change can reach 56 W/m², and its relative change amplitude reaches 34%. The new method agrees with the actual phenomenon of the mountain.