1. NOAA Center for Atmospheric Sciences and Meteorology, Howard University, Washington, DC 20009, USA
2. National Center for Atmospheric Research, Boulder, CO 80301, USA
3. NOAA/NESDIS/STAR, College Park, MD 20740, USA
4. NASA/GSFC/SSAI/BSB, Greenbelt, MD 20771, USA
5. Physics Department, University of Maryland Baltimore County, Baltimore, MD 21250, USA
6. School of Mathematical and Natural Sciences, Arizona State University, Tempe, AZ 85281, USA
7. NOAA/ESRL/PSD, Boulder, CO 80305, USA