Error estimation of spectral parameters for high-resolution wind and turbulence measurements by wind profiler radars

Abstract

Using numerical simulations, we investigated a method for calculating the spectral parameters from Doppler spectra collected by high-resolution wind profiler radars (WPRs). Because high-resolution WPRs collect a huge amount of Doppler spectra, calculations must be simple and fast. The proposed method has two steps. In the first step, the echo range (R echo ), in which the Doppler spectrum point with peak intensity is contained and all the smoothed Doppler spectrum points have intensities that are greater than the noise intensity, was determined. For producing the smoothed Doppler spectrum, a running average with equal weight (RA) or multitaper method (MTM) was used. In the second step, the spectral parameters were calculated using the Doppler spectrum points within R echo . By comparing the performance of the computation methods using RA and MTM, we concluded that the computation method using RA is more suitable because it has better estimation performance for small spectrum widths and the calculations are faster. Estimation error of the spectral parameters depends on the determination accuracy of the Doppler spectrum peak and R echo . Furthermore, for the case of a 512-point Doppler spectrum and 13-point RA, the estimation errors tend to be independent of the signal-to-noise ratio (SNR) when the peak level of the Doppler spectrum (p est ) is ∼8 dB or more greater than the noise intensity. For p est of < ∼8 dB, the estimation errors are well correlated to p est and the SNR. Therefore, the number of incoherent integration times should be determined by considering the SNR and p est .

Spectral parameters estimation in precipitation for 50 MHz band atmospheric radars

“…By using numerical simulation and a method which uses a noise level for determining an echo threshold (bottom method), we evaluated the performance of the two methods. Gan et al [] (hereafter G14) describe details of the bottom method. In section 3, by using the measurement results obtained by the vertical beam of the 46.5 MHz middle and upper atmosphere radar (MU radar) during a precipitation event, the top and two‐echo methods are validated.…”