Measuring rain drops, modelling weather, managing radio communications

Dr. Merhala Thurai-Rajasingam of Colorado State University in the United States has published research that takes into account new techniques for measuring raindrop distortion to enable better weather forecasting. The 2D video Distrometer developed by DIGITAL delivered the highly accurate measurements.

DI(FH) Günter Lammer (JOANNEUM RESEARCH) in the Distrometer Laboratory. Credit: JOANNEUM RESEARCH/B. Bergmann


"The weather is almost ready to become human-made" said a German philosopher Manfred Hinrich.

The state‐of‐the‐art research provides innovative insights into physical properties of weather patterns and leads to the better weather forecasting. The study “Tracking changes in falling raindrops” addresses the issue of variety of rain types and locations and explores the correlation between the various environmental factors and the raindrop shape, size and fall velocity distributions.

The head of the study Dr. Merhala Thurai-Rajasingam from the Department “Electrical and Computer Engineering” at the Colorado State University explains the motivation: “My interest in rain drop characteristics stemmed from my work relating to atmospheric effects on radiowave propagation, in particular the effects in rain. With developments in instruments such as the 2D video Distrometer, it became possible to characterise the essential parameters such as shapes and fall velocities on a statistical basis. Together with developments in polarimetric weather radar worldwide, we can now study the variations in a variety of rain types and locations. I have worked with many colleagues with genuinely shared interests in this topic.”


The collaboration of researchers from USA and Austria has used 2D video distrometer and custom software, developed by Dr. Michael Schönhuber, the head of research group “Space and Communication Technology” at the Institute DIGITAL of JOANNEUM RESEARCH. The 2D video Distrometer provides the necessarily detailed information: precipitation particles (raindrops, for example), filmed from the front and the side with two high-speed cameras are measured with a high degree of accuracy. Reliable models for the fine structure of precipitation are basic requirements for a wide range of applications in telecommunications, remote sensing and meteorology.

The performed study has important implications for weather forecasting and enables more efficient and precisely detection of rainfall over wide geographical areas.