为了定量分析建筑物对地面辐射的影响, 利用吐鲁番气象站周边6座典型建筑物的方位角、高度及其与观测场的距离, 建立了气象站周边建筑对日照时数影响的定量计算方法, 并引入理论影响、理论有效影响和实际影响等三类参数进行了分析。结果表明, 仅考虑天文计算, 则6座建筑对吐鲁番日照的理论遮挡时数为882.9 h, 理论遮挡比例为19.9%; 考虑日照计对直接辐射辐照度的响应阈值, 去除太阳高度角<5°的情形, 得到6座建筑对日照的理论有效遮挡时数为633.1 h, 理论有效遮挡比例为14.2%; 当考虑真实天气条件时, 得到6座建筑对日照的实际遮挡时数在145.4~592.7 h之间, 实际遮挡比例在3.3%~13.3%之间。从每座建筑的独立影响看, 位于观测场南侧的2座建筑, 由于其高度较高或距离太近, 有效遮挡比例最大; 从季节变化看, 冬季太阳高度角低, 日照被遮挡最严重, 秋季次之, 春、夏季较轻。

Taking Turpan meteorological station as an example, and considering the azimuth and height of six typical buildings surrounding it as well as the distance between the observation field and the six typical buildings, a quantitative calculation method of effects of buildings surrounding the meteorological station on sunshine hours was established. In the concrete analysis, three types of parameters including theoretical influence, theoretical valid influence and real influence were introduced. The results showed that if the focus was confined to astronomical calculations, the theoretical block hours of sunlight by the six buildings were 882.9 h and the theoretical block proportion was 19.9%. The response threshold of sunshine recorder on direct radiation irradiance was further considered. When the circumstance of solar elevation angle of less than 5° was eliminated, the theoretical valid block hours of sunlight by the six buildings were 633.1 h, and the theoretical valid block proportion was 14.2%. When the real weather conditions were considered, the real block hours of sunlight by the six buildings were in the range from 145.4 to 592.7 h and the real block proportion was in the range from 3.3% to 13.3%, according to the present data. Viewed from the independent effect of each building, the valid block proportion of two buildings located on the south side of the observation field was largest for their high height or very close distance. Viewed from the seasonal changes, the solar elevation angle in winter was low and the sunlight was shaded most seriously, followed by the solar elevation angle in autumn, spring and summer. The method can be used to calculate the influence of obstacles surround the national meteorological observation stations on sunshine, and further present a correction recommendation for the observed result of sunshine hours.