Fine-Resolution Measurement of Soil and Vegetation Moisture using InSAR Closure Phase

Events > Fine-Resolution Measurement of Soil and Vegetation Moisture using InSAR Closure Phase

Fine-Resolution Measurement of Soil and Vegetation Moisture using InSAR Closure Phase

Webinar Speaker:

Elizabeth Wig

Affiliation:

Stanford University

About the Webinar

Soil and vegetation moisture can vary spatially at the scale of agricultural fields or landscape features. Active radar provides a finer resolution than most radiometer systems; the amplitude of active radar has been used to measure soil moisture. The phase of active radar is relatively underutilized in moisture measurements. In this talk, I’ll discuss how phase measurements from active radar can be used to detect changing soil and vegetation moisture.

InSAR (interferometric synthetic aperture radar) measures a difference in phase between two radar scenes taken at different times to generate an interferogram. By calculating the phase around a loop of InSAR interferograms, we find a signal we call the closure phase. The closure phase is sensitive to changes in moisture, both in the soil and in vegetation. Here, we show that we can use InSAR closure phase from Sentinel-1 to measure changing soil and vegetation moisture over forests in the northeastern US. The closure phase signal is dominated by soil moisture changes in some areas and vegetation changes in others, or can be produced by a combination of the two. Whether measuring soil or vegetation, InSAR closure phase is a promising new method to measure changing moisture in radar images.

About the Speaker

Elizabeth Wig (Graduate Student Member, IEEE) received the B.S. and M.S. degrees (summa cum laude) in electrical engineering from Northeastern University, Boston, MA, USA, in 2020. She is currently pursuing the Ph.D. degree in electrical engineering with Stanford University, Stanford, CA, USA. Her research interests include electromagnetic wave propagation and radar remote sensing, in particular interferometric synthetic aperture radar (InSAR). She’s interested in using InSAR to measure in how vegetation and soil moisture change in dynamic environments, like agricultural areas and permafrost regions. She received the Goldwater Scholarship in 2018 and the National Science Foundation Graduate Research Fellowship, the National Defense Science and Engineering Graduate Fellowship, and the Stanford Graduate Fellowship in 2020.