A BROAD-BAND LIDAR FOR THE MEASUREMENT OF TROPOSPHERIC CONSTITUENT PROFILES FROM THE GROUND

In this paper we describe a novel lidar that combines differential UV- visible absorption spectroscopy and the lidar technique. The critical and novel element of the system is the use of an imaging spectrometer in conjunction with a two-dimensional CCD detector array to simultaneo usly spectrally and temporally resolve backscattered radiation. To exp loit this approach, the lidar system utilizes a broadband laser output of 10-20 nn full width at half maximum tunable across the UV-visible spectral region, thus allowing the simultaneous measurement of multipl e molecular species by the differential optical absorption spectroscop y technique. To demonstrate the flexibility of the technique for tropo spheric composition monitoring we present initial results for both ela stic and inelastic (Raman) backscatter and for absorption studies in t he spectral regions where NO3 and H2O absorb. In addition, the techniq ue has applicability for a wide range of molecules including O-3, NO2, and other spectrally structured absorbers and for atmospheric tempera ture sounding, which may be derived from either rotational Raman retur n or temperature dependent absorptions such as those of O-2.