Improving Hufnagel-Andrews-Phillips model for prediction [formula omitted] using empirical wind speed profiles

Abstract

Using reanalysis database of wind speed at higher altitudes acquired from the national centers for environment prediction and national centers for atmospheric research for one year 2019, the vertical profiles of optical turbulence represented by refractive index structure parameter (Cn2) were derived for two times (night and day) at twelve free-cloud days. Their dates are 4, 15 and 26 January, 7, 15 and 26 April, 2, 15 and 30 July and 2, 13 and 27 October which represent the seasons: winter, spring, summer and autumn, respectively. The Cn2 profiles extending from lower altitudes up to 25 km were calculated by the modification of single height Hufnagel-Andrews-Phillips model through establishment empirical functions for vertical variation of wind speed as functions of only height. The results show that wind profiles have highest values at night and are mostly obeyed the higher polynomial functions. In winter and spring the Cn2 profiles have significant peak values at 11 km elevation, while in another seasons the near ground Cn2 were largest and then steep decreasing at higher heights.