Autonomous, full-time cloud profiling at ARM sites with Micro Pulse Lidar

on analysis and satellite data validation. Since 1993 compact lidar instruments with the sensitivity to profile all cloud and aerosol scattering in the atmosphere have been in operation at sites of the Atmospheric Measurement Program (ARM) and have produced significant data sets. Knowledge of the vertical distribution of cloud and aerosol is of fundamental importance for atmospheric radiation science. The instruments, Micro Pulse Lidar, are special in that it is eye safe and capable of full time, unattended, highly sensitive measurements. The current ARM sites are the southern great plains facility, the north slope of Alaska and two tropical Pacific sites. The data is subject to systematic cloud processing. The currently operational cloud data products are cloud presence, the base and top height of multi layers up to the attenuation limit and the observed cloud cross section profile. Thin cloud optical thickness is a data product in development. Data have been employed in analysis of surface radiation flux. Comparison of results between sites are of interest such as the greater frequency of tropopause sub visual cirrus at the more easterly tropical Pacific site. In addition to the ARM sites there are over a dozen more MPL instruments that have been obtain by international research groups. A cooperative observation network is being formed. The overall data sets will be presented along with a discussion of applications to cloud radia