高山草甸下垫面夏季近地层能量输送及微气象特征  

Characteristics of Energy Transfer and Micrometeorology in the Surface Layer of the Atmosphere in Summer over the Alpine Meadow of the Tibetan Plateau

作　　者：李跃清[1] 刘辉志[2] 冯健武[2,3] 赵兴炳[1] 

机构地区：[1]中国气象局成都高原气象研究所,成都610071 [2]中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室,北京100029 [3]中国科学院研究生院,北京100049

出　　处：《大气科学》2009年第5期1003-1014,共12页Chinese Journal of Atmospheric Sciences

基　　金：中国气象局数值模式创新基地项目"青藏高原东部及下游关键区大气边界层科学试验研究";国家国际科技合作项目2007DFB20210;四川省应用技术研究与开发项目2008NG0009;中日JICA计划"中日气象灾害合作研究中心"

摘　　要：利用青藏高原东坡理塘站2007年6～8月的观测资料,分析了高原东坡草甸下垫面夏季近地层气象要素和湍流通量日变化特征,并用涡动相关法估算地面的曳力系数。结果表明：水平风速、动量通量、摩擦速度等均在下午最大,早晨最小。二氧化碳浓度表现为早晚高、中午低的日变化特征,比湿的最大值出现在早晨。地表辐射、热量平衡各分量最高值出现在中午,最低值出现在早晨。地表反照率表现出早晚高中午低的“U”型分布,日平均值为0.164。夏季地面热源强度在白天午后表现为强的热源,在夜里表现为弱的冷、热源交替出现。夏季近地层地气热量交换中,感热输送作用小,潜热输送占主要地位。Based on the observational data of the alpine meadow surface at Litang on eastern slope of the Tibetan Plateau from June to August in 2007, the characteristics of micrometeorology elements and energy fluxes are analyzed in the paper. The drag coefficient is calculated by eddy covariance method. Results show that： the diurnal cycles of micrometeorology elements and turbulence fluxes, such as wind, temperature, sensible heat flux, latent heat flux etc., are evident. The maximum and minimum values of diurnal a...averaged variations of horizontal wind speed,momentum flux, friction velocity etc., were observed in the afternoon and at sunrise respectively. The average CO2 concentration is high from night to morning and the peak value of specific humidity emerges before sunrise. The maximum and minimum values of diurnal averaged variations of radiation and the components of heat energy balancewere observed at noon and sunrise. The surface albedo shows the variations of the ＂U＂ type in a day, with a daily mean value of 0. 164. Intensity of surface heat is analyzed to be a heat source in the daytime, while it is not obvious at night. The latent heat transfer plays a dominant role in the heat transfer between the atmosphere and the land surface in summer, while the sensible heat transfer is secondary.

关 键 词：高山草甸下垫面 微气象 湍流通量 

分 类 号：P404[天文地球—大气科学及气象学]