1. UMass Lowell, Experimental Center for Environmental LIDAR, Department of Physics, Lowell, Massachusetts 01854, United States
2. Boston University, Department of Astronomy, Boston, Massachusetts 02215, United States
3. UMass Boston, School for the Environment, College of Science and Mathematics, Boston, Massachusetts 02215, United States
4. Boston University, Department of Earth and Environment, Boston, Massachusetts 02125, United States