Department of Meteorology, Pennsylvania State University, University Park, PA, USA

now at: Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA

Department of Meteorology, Pennsylvania State University, University Park, PA, USA

Rosenstiel School of Marine and Atmospheric Science, University of Miami, FL, USA

now at: Air Resources Laboratory, National Oceanic and Atmospheric Administration, Silver Spring, MD, USA

Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA