丽江高美古视宁度、等晕角及相干时间的探空测量

Measurements of Seeing,Isoplanatic Angle,and Coherence Time by Using Balloon-borne Microthermal Probes at Gaomeigu

对高美古的折射率结构常数C_n^2廓线和常规气象参数廓线进行了探空测量.实验期间,白天视宁度ε_(FWHM)为3〃,等晕角θ_0为0.3〃,相干时间τ_0为0.4 ms左右.夜晚ε_(FWHM)为1.04〃,θ_0为1.00〃,τ_0为1.84 ms.通过计算TER(turbulent energyratio)以及Richardson数表明,视宁度主要来自近地面层和自由大气层湍流的贡献,边界层湍流贡献不大.距地面几米的强湍流层、对流层顶附近强湍流层以及风速梯度变化较大所对应的强湍流层构成了高美古湍流空间分布的主要特征.

The profiles of Cn2 and meteorological data have been measured by using the bMloon-borne microthermal probes at Gaomeigu. We find the seeing of 3H, the isoplanatic angle of 0.3t~, and the coherence time of 0.4 ms in daytime, and the seeing of 1.04H, the isoplanatic angle of 1.00~t, and the coherence time of 1.84 ms in nighttime, respectively. Through the analysis of TER （turbulent energy ratio） and Richardson number, the main contribution to the seeing at Gaomeigu is produced by the surface layer and free atmo- sphere, the boundary layer is not important. The strong turbulent layer associated with a few meters above the ground, highly wind shear, and tropopause is the main characteristic of turbulent spatial distribution at Gaomeigu.