Summary of the Experimental Cloud Lidar Pilot Study ( ECLIPS ) at ISTS/York Lidar Observatory

Clouds play an important but complex role in modifying the solar radiative transfer in the atmosphere. To gain better insight into cloud physical and optical properties, which form the basis for cloud parameterization in general circulation models, the ECLIPS [1] was initiated in which about a dozen lidar groups have participated. The ECLIPS program has provided an opportunity to conduct lidar measurements of cloud systems simultaneously observed by a satellite (NOAA-10 or 11). A lidar measurement time series, typically of 3 hours encompasses a satellite overpass. Two ECLIPS phases (Sep-Nov 1989, Jun-Jul 1991) have provided consistent cloud lidar measurement time series on a variety of cloud formations. Our achievements in developing analytical methodologies to utilize large amounts of lidar data and to extract information on cloud physical and optical parameters are summarized in this paper. The behaviour of lidar derived cloud parameters in relation to important meteorological parameters will also be discussed.