1. School of Geosciences, University of Oklahoma, 100 East Boyd Street, Norman, Oklahoma 73019, USA
2. Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, Fairfax, Virginia 22030, USA
3. Department of Atmospheric and Planetary Sciences, Hampton University, 21 East Tyler Street, Hampton, Virginia 23668, USA
4. Space Science Institute, 4750 Walnut St., Suite 205, Boulder, Colorado 80301, USA
5. Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109-1005, USA