Abstract
Concurrent measurements of three-dimensional wind velocities made with three co-located wind profilers operated at frequencies of 52 MHz, 449 MHz, and 1.29 GHz for the period 12–16 September 2017 are compared for the first time in this study. The velocity–azimuth display (VAD) method is employed to estimate the wind velocities. The result shows that, in the absence of precipitation, the root mean square difference (RMSD) in the horizontal wind speed velocities U and wind directions D between different pairs of wind profilers are, respectively, in the range of 0.94–0.99 ms−1 and 7.7–8.3°, and those of zonal wind component u and meridional wind component v are in the respective ranges of 0.91–1.02 ms−1 and 1.1–1.24 ms−1. However, the RMSDs between wind profilers and rawinsonde are in the range of 2.89–3.26 ms−1 for horizontal wind speed velocity and 11.17–14.48° for the wind direction, which are around 2–3 factors greater than those between the wind profilers on average. In addition to the RMSDs, MDs between wind profilers and radiosonde are around one order of magnitude larger than those between wind profilers. These results show that the RMSDs, MDs, and Stdds between radars are highly consistent with each other, and they are much smaller than those between radar and rawinsonde. This therefore suggests that the wind profiler-measured horizontal wind velocities are much more reliable, precise, and accurate than the rawinsonde measurement.
Highlights
Introduction iationsWith the implementation of the coherent integration technique at the Jicamarca veryhigh-frequency (VHF, 30–300 MHz) radar, making it possible to measure the atmospheric wind and turbulence in the early 1970s [1], the notion of wind profiles to detect the echoes backscattered by atmospheric refractivity irregularities at Bragg scale exclusively for wind and turbulence measurement emerged
Due to differences in operating frequencies and radar parameters set for echo signal processing, such as pulse width, coherent integration, bit number of phase code, data points of FFT, and so on, which determine the signal-to-noise ratio (SNR) of the radar returns, there are differences in the height coverages of the wind measurements of the VHF, UHF, and L-band wind profilers
We summarize the values of the statistical parameters, i.e., C.C., root mean square difference (RMSD), mean of difference (MD), and standard deviation of difference (Stdd), of the U, D, u, and v components in Tables 2 and 3 to facilitate comparisons
Summary
Introduction iationsWith the implementation of the coherent integration technique at the Jicamarca veryhigh-frequency (VHF, 30–300 MHz) radar, making it possible to measure the atmospheric wind and turbulence in the early 1970s [1], the notion of wind profiles to detect the echoes backscattered by atmospheric refractivity irregularities (or clear air turbulences) at Bragg scale exclusively for wind and turbulence measurement emerged. The horizontal wind velocities measured by wind profilers have long been compared with those observed by rawinsonde. There are two primary methods implemented in a wind profiler to measure the wind velocity, namely the Doppler beam swing (DBS) and velocity–azimuth display (VAD) methods. For the DBS method, threedimensional wind velocity is estimated from the Doppler (radial) velocities by steering the radar beams in the vertical and several (at least two mutually orthogonal) azimuthal directions at specific zenith angles (usually greater than 12◦ to avoid the underestimation of the horizontal wind velocity caused by the aspect sensitivity effect) [17], respectively
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