The multiple-mirror lidar '9-eyes'

The Institute of Atmospheric Physics is developing a large lidar system for atmospheric remote sensing. It will be installed in two containers, to fac ilitate its deployment at different locations for measurement runs. The emi tted wavelengths are 532 and 355 nm, and are obtained with a Nd:YAG laser. The receiver includes three light collectors to split the large dynamic ran ge of the signal incident on each photodetector. The major receiver, to be used for the observation of the middle atmosphere, is an array of nine 0.5 m diameter telescopes (hence the name '9-eyes'). The advantage of the multi ple-mirror technique, with respect to a single-mirror receiver, is mainly i n the reduced volume, for the same receiving surface (and hence lower cost and transportability). Moreover, the system architecture allows for flexibi lity in the use of different observation geometries. The other two light co llectors are smaller single telescopes, and will be used for the observatio n of the lower layers of the atmosphere (troposphere and lower stratosphere ). Vertical profiles extending from the boundary layer to the mesopause are expected from this instrument, corresponding to a luminous signal spanning over 13 orders of magnitude. Detection of elastic backscattering yields th e aerosol profile and information on clouds (base height, optical and geome trical depth of thin clouds). It also provides the molecular density and te mperature above similar to 30 km. In the final configuration, the system wi ll also be equipped for the detection of the Raman-scattered signal from N- 2 and H2O, to supply the corresponding vertical distributions.