We combined radar data from two frequencies for a case of stratiform rainfall in Japan to estimate the relationship between raindrop size and number concentration aloft. One of the radars used operates at a frequency close to that of satellite-mounted precipitation radars. However, even for stratiform rainfall expected under calm atmospheric conditions, data corrections are required, suggesting that challenges remain for the application to satellite observations.

Over a 3-week period, simultaneous measurements were conducted using a Doppler lidar and a 1.3 GHz radar wind profiler in Japan. Although the instruments had no range overlap, turbulence kinetic energy dissipation rates were estimated through various methods in convective boundary layers. Hourly averaged estimates showed good agreement, within a factor of approximately 2, suggesting that both instruments and methods provide consistent dissipation rate values.

Doppler radars can be used to estimate turbulence kinetic energy dissipation rates in the atmosphere. The performance of various models is evaluated from comparisons between UHF wind profiler and in situ measurements with UAVs. For the first time, we assess a model supposed to be valid for weak stratification or strong shear conditions. This model provides better agreements with in situ measurements than the classical model based on the hypothesis of a stable stratification.

Small-scale turbulent structures are ubiquitous in the atmosphere, yet our understanding of their structure and dynamics is vastly incomplete. IDEAL aimed to improve our understanding of small-scale turbulent flow features in the lower atmosphere. A small, unmanned, fixed-wing aircraft was employed to make targeted observations of atmospheric columns. Measured data were used to guide atmospheric model simulations designed to describe the structure and dynamics of small-scale turbulence.