Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Baltimore, MD, USA

also at: The Atmospheric Chemistry and Dynamics Branch, NASA Goddard Space Flight Center, Greenbelt, MD, USA

Department of Environmental Sciences & Engineering, University of North Carolina, Chapel Hill, NC, USA

Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Baltimore, MD, USA

also at: The Atmospheric Chemistry and Dynamics Branch, NASA Goddard Space Flight Center, Greenbelt, MD, USA

Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, NJ, USA

Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Baltimore, MD, USA

also at: The Atmospheric Chemistry and Dynamics Branch, NASA Goddard Space Flight Center, Greenbelt, MD, USA