INSTRUMENTS ,

The Laser, Molecular Spectroscopy and Quantum Chemistry Group of the University of Murcia has been developing a stationary lidar system to monitor the atmosphere over the city of Murcia within the projects 01733/CV/98 and PI00798/CV/01 of the Murcia Region’s Research Coordination Centre, and HF2000-0055, FIT-020100-2001-75, FIT-020100-2001-564, FIT-020100-2002-485, BQU2001-0142 and CTQ2004-07818-CO2-01 of the National Research and Development Plan. The University of Murcia’s lidar, installed in the laboratories of the Physical Chemistry Department of the Chemistry Faculty, is a biaxial monostatic system equipped with a Q-switch pulsed Nd:YAG laser with a frequency doubler capable of emitting electromagnetic radiation pulses of a duration between 5 and 10 ns at the wavelengths of 1064 nm (1 J maximum power), 532 nm (500 mJ maximum power), 355 nm (250 mJ maximum power) and 266 nm (110 mJ maximum power) with a triggering frequency of 10 Hz. The radiation generated is projected into the atmosphere by means of a dichroic mirror mounted on a computer-controlled motorised platform, which enables it to perform vertical and horizontal sweeps. Reception is by means of a 35 cm telescope, also motorised, which projects the light towards a monochromator equipped with optimised diffraction networks to work in the close-infrared, visible and ultraviolet region. Detection is by means of a broad-spectrum photomultiplier with a maximum response between 300 and 800 nm. The electrical signals are acquired by means of a Boxcar system equipped with integrators, amplifiers and a digitisation system. This equipment makes it possible to detect elastic pulses at 532 nm and inelastic pulses from Raman backscattering of radiation at 355 nm.