A Comparative Spectral Analysis of Atmospheric Radar Signal Processing by Using HHT with FFT Algorithm

Radar probing of the atmosphere with high power VHF radars offers a powerful means to explore the structure and dynamics of the middle atmosphere with unprecedented height and time resolutions. Nowadays, atmospheric radars are extensively used for obtaining the wind information (wind profiler) by remote sensing of the atmosphere from the ground. The wind profiling radar system is an extremely versatile and high performance instrument for studies of the lower and middle atmosphere. Wind profilers data are widely used in the meteorological community for research and for the initialization of forecast models. However, any systematic velocity errors, such as those caused by any interference, make these data potentially less valuable or even damaging for analysis and prediction. Therefore, identification of atmospheric signals from the radar backscattered echoes and computation of wind velocity is significant in the atmospheric radar data processing. It is possible with the sophisticated signal processing techniques to improve the accuracy of the wind velocities measured by the wind profilers. A new data analysis approach for signals generated through nonlinear and nonstationary process based on the Empirical Mode Decomposition (EMD) method and Hilbert Transform (HT) was developed and the analysis was carried out on atmospheric signals. The same technique was compared with existing signal analysis technique such as Fast Fourier Transforms (FFT) and it was found to give considerable advantage in identifying the frequencies in finer resolution.