Structure function calculations of convective turbulence during COPS

The Convective and Orographically-Induced Precipitation Study, COPS was conducted in the Black Forest region of Germany during the summer of 2007. Its aim was to advance the quality of forecasts of orographically-induced convective precipitation by 4D observations and modeling. The UK‘s University‘s Facility for Atmospheric Measurement, UFAM, was funded through NERC to participate in the project. The University of Salford collected a variety of atmospheric data products from a range of ground based and remote sensing instruments. The University of Salford instrumentation included a 1.5 micron Doppler lidar system mounted in a mobile laboratory with a full hemispheric scanning capability, a 14 channel microwave radiometer and an automatic weather station (AWS). All Salford instruments were set up to run continuously from 13th June to 16th August 2007. The Doppler lidar was controlled remotely via an internet link.

This dataset has been used to calculate boundary layer turbulence properties. The diurnal cycle of the turbulent behaviour within the mixed layer has been investigated using spectral and simple turbulence modelling methods. Using a von Kármán model fit to the structure function data. Timeseries of turbulent length scale (outer length scale) and energy dissipation rate have been calculated. Results give a unique view of convective boundary layer behaviour.