1. Stevens Institute of Technology, Castle Point on Hudson; Davidson Laboratory; Hoboken NJ 07030 USA
2. NASA Goddard Institute for Space Studies; New York NY 10025 USA
3. Portland State University; Department of Civil and Environmental Engineering; Post Office Box 751 Portland OR 97207 USA
4. Now at Earth Resources Technology, Inc.; NOAA Coast Survey Development Lab; 1315 East West Highway Silver Spring MD 20910 USA