Abstract
Cross-polarized temporal coherence observations of a boreal forest, acquired using a tower-based radar, are presented in this article. Temporal coherence is analyzed with respect to frequency, temporal baseline, time of day of observation, season, meteorological variables, and biophysical variables. During the summer, P- and L-band temporal coherence exhibited diurnal cycles, which appeared to be due to high rates of transpiration and convective winds during the day. During the winter, freeze-thaw cycles and precipitation resulted in decorrelation. At temporal baselines of seconds to hours, a high temporal coherence was observed even at C-band. The best observation times of the day were midnight and dawn. Temporal coherence is the main limitation of accuracy in interferometric and tomographic forest applications. The observations from this experiment will allow for better spaceborne SAR mission designs for forest applications, better temporal decorrelation modeling, and more accurate forest parameter estimation algorithms using interferometric and tomographic SAR data.
Highlights
T EMPORAL coherence is the complex correlation coefficient between two coherent radar observations acquired at different times with the same observation geometry
Temporal coherence matrices provide a representation of how the temporal coherence varies for different temporal baselines (t2−t1) and different reference times (t1)
Temporal decorrelation is a major limitation in forest applications of interferometric and tomographic synthetic aperture radar (SAR) data
Summary
T EMPORAL coherence is the complex correlation coefficient between two coherent radar observations acquired at different times with the same observation geometry. Temporal coherence is a measure of observation quality for interferometric and tomographic synthetic aperture radar (SAR) applications and a source of information about the observed scene [1]–[5]. A reduction in temporal coherence (temporal decorrelation) is caused by natural and anthropogenic changes in the geometry or dielectric properties of the scatterers within a resolution cell between two observations [6], [7]. Temporal decorrelation in interferometric and tomographic SAR observations is a major limitation to the estimation accuracy of Manuscript received August 11, 2020; revised January 25, 2021 and March 30, 2021; accepted April 10, 2021.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
