Comparison of horizontal velocity measurements between the ST-VHF Provenceradar and a VHF small profiler using two different antenna configurations

In the classical development of wind profiler systems, the VHF range (40-60 MHz) has been generally selected for high altitudes explorations (ST and M ST systems) and the UHF range oriented mainly towards low altitudes soundin gs (T systems). Preliminary experiments in LSEET have shown that it was pos sible to investigate as low as 300 m with a low-power, small 50 MHz profile r radar in a classical configuration (squared, nxn). Bur using a small ante nna array involves an increasing of the half-power beamwidth and of the ove rlapping in adjacent gates in oblique directions, and inverse methods have to be applied for atmospheric parameters retrieval. A new configuration of the antenna (two crossed lines) leads to decrease the oblique angle and the half-power beamwidth, and allows to reduce overlapping between adjacent ga tes. In this paper, measurements from the small profiler in these two diffe rent configurations (squared and crossed configurations) and from the Prove nce radar (reference radar) will be: compared, without using inverse method s. Validities of small radar measurements for horizontal velocities will be given in a quantitative way, as a function of the altitude and of the sign al-to-noise ratio. Conclusions will be clearly exposed, and will indicate t hat measurements from the small profiler in crossed configuration ape not s trongly affected by overlapping, and that then horizontal velocities can be interpreted directly without using inverse methods.