Longterm measurements and statistics study on refractiveindex structure parameter of surface layer

The data of refractive index structure parameter from 1997 to 2000 at a complex terrain in Hefei are studied statistically. Results of refractive index structure parameter in different ground covers, different seasons, different heights are presented. Months goes when refractive index structure parameter in daytime from strong to weak are June, May, April, September, January. The refractive index over the grass are larger than that over the water in daytime, while the result of the comparison in nighttime is the reverse. The refractive index decreases with altitude increase both in day and at night. The refractive index structure parameter falls slower from 3 to 10m than 10 to 15m. refractive index measured and modeled agree well with each other.