exponential model for the radio refractive index in iran, based on data of radiosonde sites

in this paper, some meteorological data, such as temperature, pressure and dew point temperature are used for extracting the atmospheric refractivity in different locations of iran. these data have been measured at different heights in twelve radiosonde sites of country by using meteorological balloons. the set of refractivity points obtained from data of each site are plotted as a function of height for each month of year and a proper exponential curve is fitted on them. these models are used in design of satellite links and estimation of radar coverage. in addition, two exponential curves named upper and lower bounds are introduced, so that 98% of the refractivity points lie between these two curves. finally, the coefficients of the obtained exponential curves are presented for the four months of year in three tables. using these tables, two examples of the monthly refractivity maps of iran is also plotted.