The scope of this thesis is to investigate the effect of inhomogeneous atmospheric condition on sound wave propagation from a line source array. It is founded in the analysis that inhomogeneous wind condition refracts the sound wave and the Sound Pressure Level (SPL) coverage of the line source array is uneven. A solution is proposed to minimise the SPL coverage differences in the line source coverage area. The solution deals with both crosswind and parallel wind. In the parallel wind case, only upwards refraction is analysed. Measurement shows that the SPL coverage can be optimised from a difference of over 17dB to less than 3dB between the upwards and downwards direction. Moreover, the SPL in the shadow zone is raised in parallel wind condition by forward tilting of the line source array.