Improvement of laser Doppler anemometer results by simultaneous backscatter measurements

Infrared Doppler lidar systems have proven very efficient for remote measurements of atmospheric wind and turbulence. During the last five years the cw CO2 laser Doppler anemometer (LDA) from DFVLR has been successfully used for different routine applications, for example, the measurement of vertical wind profiles up to 750 m altitude or wind profiles close to the sea surface. Another type of applications covers the investigation of turbulence structures, especially the detection and tracking of aircraft wake vortices. Despite all the accurate results gained during these and additional field experiments, some difficulties became evident which can influence the LDA measurements in unfavourable cases. One of those cases is the presence of strongly scattering layers like fog or low clouds within or nearby the sensing volume. This paper describes the possibilities which arise by simultaneous measurements of aerosol profiles and cloud heights using a backscatter lidar and a ceilometer.