利用Thorpe尺度估算南极点大气湍流廓线

ESTIMATING THE PROFILES OF ATMOSPHERIC TURBULENCE ABOVE THE SOUTH POLE BY THORPE SCALE

分析了南极点(South Pole)2012年常规气象参数探空数据,统计了南极点全年的边界层高度分布,利用Thorpe尺度估算了南极点夏季及冬季的折射率结构常数Cn^2、大气相干长度、视宁度、等晕角等参数和边界层高度以上及边界层内的视宁度及其对整层(0—25 km)视宁度的贡献,将之与文献结果比对。结果表明:估算的Cn^2在近地面随高度迅速递减,300 m后随高度缓慢减小,5 km以后出现一个鼓包,10 km后随高度稳定递减,都呈现湍流主要集中于300 m以下这一特点。用Thorpe尺度估算的南极点冬季整层视宁度为1.87",270 m以上高度视宁度为0.39",与文献报道较为吻合。Thorpe尺度相较于其他外尺度模式估算过程更为简便。

Based on analysis of conventional meteorological parameters of sounding data above the South Pole in 2012,this study determined the boundary layer height above the South Pole throughout the entire year and used the Thorpe scale to estimate the refractive index structure constant profiles,atmospheric coherence length,seeing and isoplanatic angle.The seeing above and within the boundary layer and its integrated contribution to the entire layer(0 25 km)was compared with results in the literature.The comparison showed that the estimated profiles of Cn^2 decreased rapidly with height near the ground,decreased slowly above n 300 m,presented a bulge after 5 km and decreased steadily after 10 km.Moreover,they were characterized by the fact that most of the turbulence was concentrated below 300 m.In winter above the South Pole,the Thorpe scale estimate of the average seeing and the seeing below 270 m was 1.87"and 0.39",respectively,consistent with the results of other studies.However,in comparison with other models,the estimates can be obtained more easily using the Thorpe scale.