Remote sensing of atmospheric aerosols and water vapor in the lower troposphere are carried out at the University of Maryland, Baltimore County (UMBC) by the Atmospheric Lidar Group. Elastic (532 nm) by the Elastic Lidar Facility (ELF) and Raman (355, 386, 407 nm) lidar measurements from the Atmospheric Lidar Experiment (ALEX) support a number of current experiments: the Regional East Atmospheric Lidar Mesonet (REALM), which monitors air quality in the vertical from multiple locations on the eastern coast of the United States, the North American component of the Global Atmospheric Watch Aerosol Lidar Observation Network (GALION), validation of CALIPSO/OMI instruments on the NASA's A-Train, and for the Water Vapor Variability – Satellite/Sondes (WAVES) campaign.

For lofted layers encountered above the planetary boundary layer, the extinction to backscatter ratio (Sa) was computed to determine the aerosol extinction and subsequently the optical depth. Depolarization and attenuated color ratios from observables from the lidar systems were calculated to aid in the identification of aerosol speciation and characterization. Synergistic observations from instruments from the A-Train were used to identify the horizontal and vertical extent of these atmospheric scatterers. This paper will present the results obtained over the 2004-2007 timeframe. In particular, observation of low-level jet activity over the Baltimore site shows the utility of frequent lidar observations coupled with a wind profiler at night.