Research continuum


MU Radar Observations Atmospheric Turbulence

MU Radar

In collaboration with a French research group, we conducted an extensive study on the small-scale dynamics of the lower atmosphere. The study aims to characterize atmospheric turbulence, its sources and its interactions with largescale dynamics and clouds by means of remote sensing and in situ observations.
The Middle and Upper atmosphere (MU) radar of the Research Institute for Sustainable Humanosphere (RISH) is one of the most suitable instruments for detecting turbulence and stable interfaces throughout the entire troposphere at any time, irrespective of clear or cloudy conditions. In turbulence observations, excellent spatial and temporal resolutions can be achieved through a range-imaging technique using frequency diversity.
In recent years, all the measurement campaigns have involved the MU radar in range-imaging mode with complementary instruments (e.g. radiosondes, Rayleigh-Mie lidars, ultra high frequency [UHF] and meteorological radars) for validating the technique in turbulence studies. The bottom figure shows an example of a time-height cross section of echo power obtained using the MU radar in range-imaging mode on 8 October 2008. We found Kelvin-Helmholtz (KH) braided-like structures along the slope of a cloud base gradually rising with time at an altitude of approximately 5 km, and vertical air motion oscillations exceeding ±3 m/s with a period of approximately 3 min above and below the cloud base.

Hiroyuki Hashiguchi, PhD
Associate Professor, Research Institute for Sustainable Humanosphere