In October 2013, I (Sophia Schäfer) was seconded to Susanne Crewell’s research group at the University of Cologne for 2 weeks. In my project, I will use data from the Jülich ObservatorY for Cloud Evolution (JOYCE) scanning cloud radar to reconstruct 3D cloud fields and develop a statistical parametrisation for the area of cloud sides, depending on cloud type, for use in a 3D radiation scheme. Goals of the secondment were to get acquainted with the measuring strategies used at JOYCE, the available data and possible artefacts, adapt an interpolation scheme for that data and decide on a choice of cases that are representative and allow intercomparison with work done in Cologne.

I worked on retrieving the data from crosswind RHI scans (elevation scans in a plane perpendicular to the wind, that cover the cloud field as it is blown across the radar’s field of view, as seen below), correcting for variations in wind direction and interpolating it onto a regular spatial grid. As a next step, I developed an algorithm to retrieve the cloud side area from the reflectivity field.

Many thanks to the whole group for the great reception, and especially to Susanne Crewell, Claudia Acquistapace, Kerstin Ebell, Pavlos Kollias and Thijs Heus, for highly profitable discussions on the best choice of cases, comparison with simulations, scaling effects, possible modifications of future measurements and error sources in the data, that sparked many ideas for my future work.