The Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) program is a key component of the DOE’s research strategy to address global climate change. The ARM program is a highly focused observational and analytical research effort that will compare observations with model calculations in the interest of accelerating improvements in both observational methodology and General Circulation Models (GCMs) and related models. The objective of the ARM program is to provide an experimental testbed for the study of important atmospheric effects, particularly cloud and aerosol processes and testing parameterizations of these processes for use in climate change models. ARM observational sites include a broad array of instruments to characterize cloud and aerosol properties as well as the background atmospheric state and the flow of radiation to the earth’s surface. Included in this array of instruments are several types of advanced lidar systems that each provides valuable information about the atmospheric column. The focus of this activity, called Combined HSRL and Raman Measurement Study (CHARMS), is to evaluate the potential of combining two lidar systems, the Raman and High-Spectral Resolution Lidar (HSRL), for providing information about aerosols and clouds that would not be possible with either of these systems on their own.