近地面湍流对整层湍流的贡献及相关研究  

Contribution of the Surface Layer to the Integral Turbulence in Northwest Plateau

作　　者：陈小威[1,2] 孙刚[1] 刘庆[1] 李学彬[1] 翁宁泉[1,3] 

机构地区：[1]中国科学院安徽光学精密机械研究所中国科学院大气成分与光学重点实验室,安徽合肥230031 [2]中国科学技术大学研究生院科学岛分院,安徽合肥230031 [3]中国科学技术大学环境科学与光电技术学院,安徽合肥230026

出　　处：《光学学报》2015年第11期48-54,共7页Acta Optica Sinica

基　　金：国家自然科学基金(41205023;41375017)

摘　　要：用由HTP-2型温度脉动仪和WXT520气象传感器组成的近地面参数测量系统以及大气相干长度仪的两年观测数据分析了西北高原地区近地面湍流。近地面参数测量系统分两层分别搭建在6 m和2 m高度上。温度脉动仪测量折射率结构常数,气象传感器测量常规气象参数,大气相干长度仪测量大气相干长度。分析结果表明:不同高度的折射率结构常数随高度按幂指数规律变化,白天幂指数平均值为-0.8,夜间为-0.3。用相干长度比评估近地面湍流层对整层湍流的贡献,结果表明:相干长度比有明显的日变化特征,白天小而夜间大;不同月份相干长度比日变化趋势和大小均不同。讨论了近地面局地视宁度与局地温差的关系,结果表明:局地视宁度和局地温差白天正相关,夜间负相关。Results from experiments measuring surface layer turbulence in Northwest China are presented. The measurements are taken over two years using surface layer atmospheric parameter system and differential image motion monitor.The surface layer atmospheric parameter system is composed of HTP-2 microthermal sensors and WXT520 meteorological sensorsis placed at 2 m and 6 m on a mast. Microthermal sensors are used to measure structure constant of refractive index and meteorological sensors are used to measure meteorological parameters. It is observed that structure constant of refractive index in the surface layer falls with exponent altitude dependence with the power index of -0.8 in the day and -0.3 at night. The contribution of surface layer to the integral turbulence is estimated using coherence length ratio. Coherence length ratio changes in a diurnal cycle with large values in the day and small values during the night and the changing trend and monthly averaged values are different between months. Discussion of relationship between local seeing and meteorological variables shows that local seeing correlates with temperature difference positively in the day while negatively during night. Based on longtime experiments, the results are credible and valuable in the work of site-testing and optimizing the performance of adaptive optical systems.

关 键 词：大气光学 光学湍流 天文选址 相干长度比 大气相干长度 视宁度 

分 类 号：P427.1[天文地球—大气科学及气象学]