摘要
利用国家自然科学基金项目"巴丹吉林沙漠陆-气相互作用观测试验和研究"于2009年7—9月在巴丹吉林沙漠取得的系留气球、GPS探空等加强观测资料,分析了沙漠夏季大气边界层位温、比湿及风等的日变化特征。研究表明:(1)巴丹吉林沙漠近地面气温日较差较大,比湿的变化与气温相反,白天风速变化大。(2)昼(夜)不平衡能量差额Rd>0(Rd<0),莫宁-奥布霍夫长度L<0(L>0),大气层结趋于不稳定(稳定);白天大部分净辐射能量转换为感热通量,为深厚大气边界层的发展提供热力条件。(3)午前稳定边界层经历了从重建到消退的过程,其上残留层较厚;午后混合层打通残留层发展迅速,近地面层出现明显的超绝热递减层;夜间稳定边界层迅速发展,最大厚度达900m;(4)从整个边界层来看,午前出现的5层结构在午后变为3层,稳定边界层消失,混合层迅速发展,厚度达到3 000m。夹卷层厚度最大值为1 500m,近地面的超绝热层最大达200m。
The characteristics of daily potential temperature, specific humidity, wind speed and direction of the boundary layer in summer was analyzed based on the observed data from July to September of 2009. The result showed that： （1） Surface daily temperature range was high, the variation of specific humidity was the opposite of temperature, and wind speed changed obviously at the daytime. （2） When energy imbalance item Rd〉0, Monin-Obukhov Length L〈0, the atmospheric stratification was unstable, and vice versa. The most of net radiation was transformed to sensible heat flux at the daytime, providing thermal condition for boundary layer development. （3） Stable Boundary Layer （SBL） experiences from rebuilt to disappearance, Residual Layer （RL） over SBL was thicker before noon; Mixed Layer （ML） got through the RL and develops swiftly, super-adiabatic lapse phenomenon appears at the near-surface in the afternoon; in the nighttime, SBL develops rapidly, and the maximum thickness reached 900 m, ML changed into RL. （4）To the whole atmospheric layer, five-layer boundary structure turned into three-layer structure in the afternoon, SBL disappears, ML develops and the maximum value was about 3 000 m. the thickness of entrainment zone（EZ） achieves 1 500 m and super-adiabatic layer height reaches about 200 m.
出处
《中国沙漠》
CSCD
北大核心
2014年第2期488-497,共10页
Journal of Desert Research
基金
国家公益性行业科研专项项目(GYHY201306066)
国家自然科学基金项目(41130961
41205005
40975007)资助
关键词
巴丹吉林沙漠
大气边界层
变化
Badain Jaran Desert
atmospheric boundary layer
variation
