Vertical Dependence of Refractive Index Structure Constant in Lowest Troposphere

Vertical profiles of atmospheric refractivity are indirectly measured at heights of up to 150 m above the ground using meteorological sensors located at 19 heights. The structure constant of the refractive index C_n is calculated from data measured over a one-year period using its definition relation. Linear regression in heights is applied to a structure constant vertical dependence to obtain single and joint annual statistics of the near ground value of C_n and of its vertical gradient in the lowest troposphere. Approximate probability models are given with C_n being log-normal and the vertical gradient normally distributed.