藏北高原地表反照率的初步研究

基于中日合作项目“全球协调加强观测计划之亚澳季风青藏高原试验”(CAMP/Tibet)在藏北高原D105站、Amdo站、MS3478站以及BJ站的观测数据资料,分析了该地区地表反照率的时空分布特征。结果表明:藏北高原地区的地表反照率具有明显的日变化和月/季节变化特征。冬、春季的日变化曲线呈“U”形,且曲线形状的变化不如夏、秋季大。6~9月的月平均反照率在全年中最低,5月份月平均反照率波动较大。从季节平均值来说,冬季>春季>秋季>夏季。该地区的平均地表反照率为0.2457;反照率的空间分布很不均匀,其值的大小、曲线的形状在不同站点都很不一样,这与站点的地理位置有关,但天气状况和下垫面属性也起了很大的作用。

A Preliminary Study on Land-Surface Albedo in Northern Tibetan Plateau

Based on the observed data at Automatic Weather Stations(AWS) including D105,Amdo,MS3478 and BJ in northern Tibetan Plateau during the experimental period of CEOP/CAMP-Tibet(Coordinated Enhanced Observing Period(CEOP) Asia-Australia Monsoon Project(CAMP) on the Tibetan Plateau),the temporal variation and spatial distribution characteristics of surface albedo in this area are analyzed.The results indicate that the surface albedo in this area has obvious diurnal,monthly and seasonal variation characteristics.The diurnal variation curves in winter and spring present marked saddle shapes,and the change of curves shape is not obvious in summer and autumn.The monthly average albedos from June to September are the lowest in the whole year,and the albedo fluctuation in May is obvious.As to the seasonal average values,those in winter are the hightest,the second in spring,the third in autumn,and the lowest in summer.The average value in the region is 0.2457.The spatial distribution of albedo is also not homogeneous.Both the values and the shapes of curves are dissimilar in different stations.It relates to the geographical position of observation station,but weather condition and underlying surface situation are also very important.