Multi-beam techniques for deriving wind fields from airborne doppler radars

Abstract

Two techniques for deriving horizontal and vertical air motions using vertically scanning airborne Doppler radar data are presented and discussed. These techniques make use of the scanning ability of the NOAA P-3 tail-mounted radar antenna to view a region of space from at least two vantage points during a straight-line flight track. The scanning methodology is termed the “Fore/Aft Scanning Technique” or FAST because the antenna is alternately scanning forward and then aft of the flight track. The major advantages of FAST over flying two quasi-orthogonal flight tracks with the antenna scanning normal to the flight track are that the data are collected in roughly half the time and the aircraft does not have to execute a right-angle turn. However, accuracy of the resulting wind field is compromised slightly because the beam intersection angle is reduced from 90° to about 50°. The reduction of area covered because of large drift angles is also discussed.