1. Joint Assistant Professor, Dept. of Civil and Environmental Engineering, 3507 CEBA Building, Louisiana State Univ.-Southern Univ., Baton Rouge, LA 70803.
2. Technical Manager, Laboratory for Atmospheric and Space Physics (LASP), 1234 Innovation Drive, Boulder, CO 80303-7814.
3. Professor, Dept. of Civil, Environmental and Architectural Engineering, Campus Box 428, Univ. of Colorado at Boulder, Boulder, CO 80309-0428.