Side-Facing UHF-Band Radar System to Monitor Tree Water Status

Published in IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium, 2022

Recommended citation: Rao, K., Ulloa, Y. J., Bienert, N., Chiariello, N. R., Holtzman, N. M., Quetin, G. R., et al. (2022). Side-Facing UHF-Band Radar System to Monitor Tree Water Status. In International Geoscience and Remote Sensing Symposium (IGARSS) (Vol. 2022-July, pp. 5559–5562). Institute of Electrical and Electronics Engineers Inc. https://doi.org/10.1109/IGARSS46834.2022.9883620 https://ieeexplore.ieee.org/abstract/document/9883620

Vegetation water stress is a key control on wildfire risk, tree mortality, and ecosystem water and carbon fluxes. Although active microwave remote sensing methods have been used to estimate vegetation water, they remain poorly validated because of the immense mismatch between the scale of radar pixel resolutions (100 m to 25 km) and field measurements (individual trees). In this study, we present a new plot-scale vegetation water measurement technique using a side-facing bistatic radar. Using field experiments and a matched filtering technique to isolate the radar signal from noise, we show that radar amplitude is sensitive to xylem water potential (a measure of tree water status). However, our results are affected by periodic noise (period of~12 hours), which may be due to radio frequency interference. We discuss potential pathways to isolate the signal and the implications of the new tree water status measurement system for global validation of microwave remote sensing.

Experimenting in Jasper Ridge Biological Preserve, California to develop the new radar system.

Experimenting in Jasper Ridge Biological Preserve, California to develop the new radar system..

In the news …

  1. “Treetops”, a picture clicked by Nona Chiariello during experimenting with the radar wins picture of the year in the 2020 School of Sustainability Photo Contest.