Error estimation of spectral parameters for high-resolution wind and turbulence measurements by wind profiler radars
Error estimation of spectral parameters for high-resolution wind and turbulence measurements by wind profiler radars
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风廓线雷达高分辨率风和湍流测量的光谱参数误差估计
DOI：
10.1002/2013rs005369
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
H. Okamoto and M. Yamamoto
中科院分区：
文献类型：
--
作者：
Gan;T.;M. K. Yamamoto;H. Hashiguchi;H. Okamoto and M. Yamamoto
通过数值模拟研究了高分辨率风廓线雷达采集的多普勒光谱参数的计算方法。由于高分辨率WPRs收集了大量的多普勒光谱，因此计算必须简单而快速。该方法分为两个步骤。首先，确定回波范围（Recho），其中包含峰值强度的多普勒频谱点，并且所有平滑的多普勒频谱点的强度都大于噪声强度。为了产生平滑的多普勒频谱，可以使用等权重运行平均（RA）或多锥法（MTM）。第二步，利用Recho内的多普勒谱点计算光谱参数。通过比较RA和MTM计算方法的性能，认为RA对小谱宽的估计性能更好，计算速度更快，更适合于使用RA计算方法。光谱参数的估计误差取决于多普勒谱峰和回波的确定精度。此外，对于512点多普勒频谱和13点RA的情况，当多普勒频谱（pest）的峰值电平大于噪声强度~ 8 dB时，估计误差倾向于与信噪比（SNR）无关。对于害虫< ~ 8 dB，估计误差与害虫信噪比有很好的相关性。因此，在确定非相干积分次数时，应综合考虑信噪比和干扰。
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 (Recho), 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 Recho. 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 Recho. 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 (pest) is ∼8 dB or more greater than the noise intensity. For pestof < ∼8 dB, the estimation errors are well correlated to pestand the SNR. Therefore, the number of incoherent integration times should be determined by considering the SNR and pest.