Investigation on horizontal wind estimation around high aspect sensitivity

Authors

  • Noriyuki Kawano,

  • Shoichiro Fukao


Abstract

In the present paper, simultaneous radar observations in the Doppler beam swinging (DBS), spatial interferometry (SI), and spaced antenna (SA) modes with the middle and upper atmosphere (MU) radar are shown. High aspect sensitivities were found after a passage of a cutoff low and an incidental trough owing to observations in the DBS mode. Because it is known that tilted aspect sensitivities introduce a bias in radial velocity measurements, we corrected the horizontal wind directly measured by oblique beams in the DBS mode by taking account of the arrival angle of the oblique beams estimated by the SI technique. On the other hand, the aspect angle is derived from the echo power ratio of the vertical to the oblique beams with the DBS mode, which allows us to estimate an effective pointing angle, and the Doppler wind is corrected by using this effective angle. In addition, the SA technique is performed simultaneously for estimating the horizontal wind. The above four estimating processes are used to determine the horizontal wind and compared for the aspect sensitivity. Finally, a simple computer simulation is performed for the SA technique for constant and variable wind conditions during incoherent integrations.