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Abstract
Recently the Koldewey Aerosol Raman Lidar (KARL) located at the research village of Ny Ålesund, Spitsbergen was significantly improved. Its main new features are: a) a bigger recording mirror b) a new (laser) beam widening telescopes allows smaller fields of view c) an aperture stop which is movable in diameter and position allows measurements with the very same telescope at near and far distances as well as an estimation of multiple scattering d) an additional channel for the depolarisation at 355nm is implemented (depol. at 532nm was already recorded) As before, KARL is a Nd:Yag ¡È3+2¡É Raman Lidar that can also perform water vapour (407nm and 660nm) measurements. In the past, various measurements of aerosol events have been recorded with the system. These observations allowed in the case of spherical scattering particles an estimation of the index of refraction and a size distribution in the range between 0.1 -1.25¦Ìm with long integration times. However, it is principally challenging to derive precise information of the absorption with a lidar and this hinders especially the determination of the imaginary part of the refractive index, the SSA and the number concentration of aerosol. After the redesign of the instruments new applications and aims become feasible: a) in all colours full information already at the altitude of the close by Zeppelin Station at 474m will be obtained b) the second depolarisation channel will allow an estimation of the aspect ratio (particles shape) c) multiple field of view measurements will allow an estimation for the size distribution of large crystals as in clouds. These new measurement strategies shall be briefly discussed.