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Alternative Simulation of Crop Water Radiometry
Conference proceeding

Alternative Simulation of Crop Water Radiometry

Richard Cirone, Brian Hornbuckle and Anton Kruger
2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, pp.6427-6430
IEEE International Geoscience and Remote Sensing Symposium (IGARSS) (Brussels, Belgium, 07/11/2021–07/16/2021)
07/11/2021
DOI: 10.1109/IGARSS47720.2021.9553511

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Abstract

In the summers of 2018 and 2019, a 433 MHz radio link was installed in an Iowa corn field, intended to measure the vegetation's water content. A set of three transmitters within the canopy emitted microwave radiation omnidirectionally in succession to each other, while the receiver, also within the corn canopy, listened continuously. The system was in operation for 68 days in 2018, beginning when the corn was only 0.3 m tall and ending in a full canopy environment. An increasing vegetation water content corresponded to an increasing canopy dielectric constant and thus a lower canopy transmissivity. A weakened signal received was for the most part attributed to electric field attenuation. In 2019, antennas remained in the field through October, observing the dry-down senescence as an increasing signal strength. The magnitude of air - soil reflection is another strong factor on received signal strength, as for all transmitter - receiver pairs the direct and ground - reflected signal destructively interfered. Radiative transfer models of the system often simulate the received signal to be stronger than observed. Neglecting scattering may be the cause of this error. Utilizing the software Signals of Opportunity Coherent Bistatic Scattering Simulator (SCoBi) may produce a more accurate calculation of power received.
Absorption Scattering attenuation Corn microwave Microwave measurement Radio links Radio transmitters Receivers Soil Vegetation mapping

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