敦煌荒漠戈壁地区裸土地表反照率参数化研究  

Study of Parameterization of Surface Albedo of Bare Soil over the Gobi Desert in the Dunhuang Region

作　　者：郑志远[1] 韦志刚[1] 李振朝[2] 魏红[2,3] 刘慧[2,3] 

机构地区：[1]北京师范大学地表过程与资源生态国家重点实验室,北京100875 [2]中国科学院寒区旱区环境与工程研究所寒旱区陆面过程与气候变化重点实验室,兰州730000 [3]中国科学院大学,北京100049

出　　处：《大气科学》2014年第2期297-308,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目41275011;41375001;国家重点基础研究发展计划资助2009CB421402

摘　　要：利用敦煌站观测资料，选取其中观测资料完整且连续性好的7个年份每年5-10月的地表净辐射四分量和土壤湿度资料，分析研究了敦煌荒漠戈壁地区裸土地表反照率与太阳高度角和表层土壤含水量之间的关系，结果表明：地表反照率与太阳高度角呈e指数关系，随太阳高度角的增大而减小，当太阳高度角大于40。时，地表反照率趋于稳定。表层土壤含水量的增大可导致地表反照率的减小，地表反照率与5cm深土壤湿度呈线性关系。另外，建立了敦煌荒漠戈壁地区裸土地表反照率与太阳高度角和表层土壤含水量之间的双因子参数化公式，提出了一种更加适合该地区的地表反照率参数方案，并且选取2002年6-9月的实测资料对拟合的参数化公式进行模拟验证。本文所提出的地表反照率参数化方案能够很好地再现该地区裸土地表反照率的“u”型日变化特征，可准确地模拟出地表反照率的动态变化趋势。基于此参数化方案计算得到的地表反射辐射与实测值基本一致。The relationships among surface albedo, solar elevation angle, and surface soil moisture over the Gobi desert in the Dunhuang region were analyzed by using the data of field observational surface radiation and soil moisture from May to October during a seven-year period. The results showed that the bare soil surface albedo decreases with an increase in solar elevation angle and tends to be a constant when solar elevation angle is larger than 40°. Surface albedo decreases with an increase in surface soil moisture content and shows a liner dependence on soil moisture. On the basis of the relationship of the bare soil surface albedo with the two factors of solar elevation angle and surface soil moisture content, a double factorial parameterization formula of the bare soil surface albedo is put forward over the Gobi desert in the Dunhuang region, which is more suitable for the surface albedo parameterization scheme in this area. The scheme proposed by this paper is able to reproduce the surface albedo ＂U＂ type of diurnal variation for accurate simulation of thedynamic trend of the surface albedo, in addition to accurate calculation of the bare soil surface albedo and reflected radiation. The variation characteristics as well as the trend of the bare soil surface albedo and reflected radiation are consistent with the observational data. Moreover, the calculated surface reflective radiation based on the parameterization scheme is also a good representation of the surface reflection and radiation characteristics of diurnal variation.

关 键 词：敦煌 戈壁 裸土 地表反照率 太阳高度角 土壤含水量 参数化 

分 类 号：P404[天文地球—大气科学及气象学]