上海城市日照与住宅朝向的选择

SUNSHINE IN SHANGHAI URBAN AREA AND THE CHOICE OF HOUSE ORIENTATION

上海城市日照时数和日照百分率有明显的日变化,季节变化和年际变化,这些变化除受天文因素的制约外,还受天气气候及城市人为因素的影响。城区年总日照时数小于同纬度的郊区(川沙)。并且随着城市的发展,这种城乡差距有愈来愈增大的趋势,为了获得良好的日照和通风条件,兼顾节约建筑甩地和能源消耗,上海住宅朝向以南偏东15°—30°为宜.其中以南偏东15°为最佳朝向.

On the basis of data from Shanghai Central Observatory (Longhua) and its nearby rural stations for more than 20 years,we discuss the important features of sunshine in Shanghai urban area and the choice of house orientation. 1.The diurnal and seasonal variation in sunshine in Shanghai urban area is dominant.It is caused by the latitude situation,meteorological conditions and urban artificial factors. 2.By comparing the simultaneously obtained observed data from Longhua and its nearby rural stations (Baoshan,Jiading,Chuansha and Shanghai counties),it is found that in the urban area both sunshine hours and percentage of possible sunshine are less than in rural areas. This is due to much more artificial heat,pollutants and condensation nuclei to the urban atmosphere.The obvious effect on urban climate is much more low cloudiness and overcast days but less fine days and sunshine. 3.In order to obtain good sunshine (more sunshine in winter and less sunshine in summer) and good ventilation in summer,the favorable orientation of a house in Sbanghai urban district is toward SSE.This orientation can also save the building area and energy consumption.