A systematic error in MST/ST radar wind measurement induced by a finite range volume effect: 2. Numerical considerations


  • Shoichiro Fukao,

  • Motoyuki Inaba,

  • Iwane Kimura,

  • Peter T. May,

  • Toru Sato,

  • Toshitaka Tsuda,

  • Susumu Kato


A finite range volume effect causes a systematic error in MST/ST radar wind measurement when a thin turbulent layer is simultaneously located in several adjacent range volumes. This error appears as a false vertical shear of horizontal wind or as a false temporal wind variation at some ranges even if the ambient wind field is uniform with height and does not change at all. Also, because of this effect the observed Doppler power spectrum becomes asymmetric, and a noticeable error is induced in estimation of echo power, mean Doppler velocity, and spectral width. The present investigation will show that these errors are well explained by a simple numerical model which is made to simulate an actual observational situation. The observed wind velocity is more reliable at ranges where the echo intensity is relatively larger compared with adjacent ranges. The finite range volume effect is negligibly small for weak ambient wind velocities less than approximately 10 ms−1 and/or for an antenna beam width less than one degree.