ECE PhD Student Ken Hunt receives Outstanding Student Paper Award from the American Geophysical Union

 

ECE PhD Student Ken Hunt has received the Outstanding Student Paper Award from the American Geophysical Union Hydrology Section, for his paper on " The Effects of Vegetation on Radio Signal Propagation Through a Corn Field," given at the AGU Fall 2008 meeting in San Francisco. Co-authors were ECE Professor Anton Kruger and LK Cunha of IIHR.

Abstract: As part on of an ongoing research effort, seven rain gauge platforms are deployed in a 1×1-km corn field, near Ames, Iowa. Each site transmits its data to The University of Iowa via a cellular modem operating at 2.4 GHz, at 15-minunte intervals. To monitor communications quality, the system records the received signal at each site in the field every 15 minutes. Though not collected for this purpose, the signal strength data, gathered between mid May and the end of October 2007 provide an opportunity to investigate how vegetation and water moisture in the atmospheric boundary layer affect radio signal propagation. The signal strength data are quite noisy, yet one can clearly identify a long-term trend where the signal strength decreases as the growing season progresses and the plants progressively obscure the radios' view to the cell towers. At the end of the growing season, as the plants dry out and are finally harvested, the signal strength recovers. One can explain this recovery in terms of the water-content in the plants. This is supported by the measured plant water content at different times and selected locations in the field. Spectral and other analysis of the signal strength data also reveal a subtle, yet clear diurnal variation where the signal strength from all sites in the field reaches a minimum between 1 p.m. and 2 p.m. local time. This may be explained by water vapor in the atmospheric boundary layer, probably driven by plant transpiration. Howev