Testing the IFU high-spectral-resolution lidar at the 2009 Leipzig field campaign

Abstract. The mobile three-wavelength aerosol lidar of IFU (Garmisch-Partenkirchen, Germany) was converted into a high-spectral-resolution (HSR) lidar during an extended period ending in May 2009. The system features four simultaneously operated data-acquisition channels, for the backscatter measurements (354.8 nm, 532.2 nm and 1064.4 nm) and for a spectrally filtered second 532.2-nm extinction channel. The system was successfully tested during the EARLINET-ASOS validation field campaign EARLI09 in Leipzig in May 2009, apart from systematic errors in the data that could recently be eliminated in a resumed effort. Here, we compare our results during that campaign with those of the MULIS mobile reference lidar system from the Ludwig-Maximilian University in Munich. The extinction coefficients obtained from the HSR channel and the Raman channel of MULIS agree well (within roughly ±7×10^-6 m^-1) up to vertical distances of about 5 km, with a better near-field behaviour of the HSR caused by analogue detection instead of single-photon counting. In addition, a slightly higher 532.2-nm backscatter signal relative to the Rayleigh background was obtained by the IFU lidar below 3 km. However, there are limitations in the EARLI09 signal quality of the IFU lidar due to problems with the then newly developed 40 MHz transient digitizer that can be greatly improved as known from our other lidar systems. A reasonable daytime performance was found which demonstrates the potentially high value of HSR lidar systems in a lidar network such as EARLINET.