Multi-polarisation, multi-wavelength radar measurements of ice crystals in clouds

The aim of this project is to make new multi-wavelength, multi-polarisation radar measurements of ice clouds, and use these to determine the shapes and orientations of natural ice particles and their size distribution. At Reading we have a long-standing collaboration with the Chilbolton Observatory which has a unique suite of instruments ideally suited to these kinds of measurements. We have already made substantial progress in analysis of triple-wavelength radar measurements, which have provided evidence for fractal geometry of large snowflakes, and evidence for rapid aggregation (sticking together) of dendritic ice crystals to form large clusters in certain conditions. However this is just the tip of the iceberg, and we feel there is a wealth of new information here waiting to be mined.

Specifically, we are now in a position to make measurements at different elevations, and at multiple polarisations. This offers much more information on the geometry of the particles in the cloud, and how they are oriented. This idea has been studied theoretically, but we would be the first to make actual measurements and interpret them.

More details are available on the project description at http://www.met.reading.ac.uk/nercdtp/home/available/desc/entry2017/SC201729.pdf