Monitoring of Winds in the Lower Stratosphere with the MU Radar

Environmental Assessment for the Stratospheric Radio Link System

Abstract

Height, seasonal, and short-period variations of lower stratospheric winds around 20km altitude, where aircraft for the stratospheric radio link system will fly, are analyzed based on the wind data obtained by the MU (middle and upper atmosphere) radar for three years. While the stratospheric jet stream was found to be weak enough in summer, it turned to be fairly strong in winter even at the so-called ‘zero-wind’ height of around 20km, sometime exceeding 40m/s over a period of two days. Random wind fluctuations of the order of 1m/s was found to exist in thin turbulent layers of 50-100m thickness.