石羊河流域中部太阳辐射变化的特征分析

Analysis on Change of Solar Radiation in the Central Shiyang River Basin

利用2007—2010年石羊河流域中部观测的太阳辐射资料,结合下垫面和天气变化状况,应用数理统计,综合分析太阳辐射相关因子变化。结果表明:近年来年平均总辐射、反射辐射、地表长波辐射、大气逆辐射和净辐射总量分别为6 030.9 MJ.m-2、1 596.1 MJ.m-2、11 764.7 MJ.m-2、8 892.8 MJ.m-2和1 563 MJ.m-2。年内相关辐射变化均呈单峰形,夏季(6—8月)处于高位,冬季(12月和1—2月)相对较低。地表反射率随着下垫面植被的增加逐步减小,冬季最大值为0.329,秋季(9—11月)最小值为0.241。晴好天气下除大气逆辐射近似波动的一条直线外,其余呈单峰形,一般地表长波辐射的峰值在中午前后滞后于总辐射的峰值1～2 h;阴雨雪天气,短波和长波辐射的日变化比较复杂,呈现多个峰值和谷值。春季和夏季阵性降雨后,云间大气透明度好,出现总辐射瞬时值异常增大,超过太阳常数的现象,最大超过159 W.m-2,云对辐射具有附加效应。云量影响辐射量的变化,大气逆辐射在同一季节,典型晴天值要小于多云和阴雨(雪天)天气,净辐射在日出日落前后均出现正负值之间的跳变,但云可以减少跳变的幅度。

In this study,the change of solar radiation and its affecting factors in the central Shiyang River Basin during the period of 2007-2010 was comprehensively analyzed based on the solar radiation data and considering the underlaying surface and weather conditions using the mathematical statistics.The results showed that the average annual global radiation,reflected radiation,floor long-wave radiation,atmosphere long-wave radiation and net radiation in recent years were 6 030.9,1 596.1,11 764.7,8 892.8 MJ·m-2 and 1 563 MJ·m-2 respectively.The curve of radiation was unimodal,radiation was high in summer（from June to August） but low in winter（from December to January or February）.Surface albedo was decreased with the increase of vegetation coverage,its maximum value in winter was 0.329,and its minimum one in autumn（from September to November） was 0.241.The curves of all other radiation forms on sunshine days were unimodal except the approximate beeline of atmosphere long-wave radiation.The peak value of floor long-wave radiation delayed generally for 1-2 hours than that of global radiation.The daily variation of shortwave radiation and long-wave radiation was complicated under both overcast and rainy or snowy weather conditions.An extreme high value of global radiation（159 W·m-2） occurred after a gustiness rainfall in spring and summer because of the high atmospheric transparency.Cloudage impacted directly radiation.Atmosphere long-wave radiation on sunshine days was lower than that on cloudy and rainy days and overcast,a sharp change of net radiation occurred around sunrise and sundown,but cloud could reduce the change extent.