<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The view angle range of Sentinel-1 SAR in the Interferometric Wide swath (IW) measurement mode is 29.1° – 46.0°. The dependence of backscatter on the arbitrary local incidence angle is usually corrected using a linear regression model where the incidence angle is a predictor variable. We analysed the whole time series of Sentinel-1 SAR VV-polarised backscatter over the flat 15×15 km test site in Laeva, Estonia (26° 26′ 43″ E; 58° 31′ 56″ N). Time series containing measurements from three different orbits were constructed for 3,159 stands from nighttime data and for 1,105 stands from daytime data. We can confirm that daytime backscatter is systematically greater than nighttime backscatter. We found a significant deviation from linearity in the backscatter dependence on local incidence angle. The empirical finding may be caused by the microwave scattering dependence on local incidence angle or by the influence of Sentinel-1 SAR sub-swath configuration in the Terrain Observation with Progressive Scans SAR (TOPSAR) method that is used for the measurements.</p>
</abstract>

The view angle range of Sentinel-1 SAR in the Interferometric Wide swath (IW) measurement mode is 29.1° – 46.0°. The dependence of backscatter on the arbitrary local incidence angle is usually corrected using a linear regression model where the incidence angle is a predictor variable. We analysed the whole time series of Sentinel-1 SAR VV-polarised backscatter over the flat 15×15 km test site in Laeva, Estonia (26° 26′ 43″ E; 58° 31′ 56″ N). Time series containing measurements from three different orbits were constructed for 3,159 stands from nighttime data and for 1,105 stands from daytime data. We can confirm that daytime backscatter is systematically greater than nighttime backscatter. We found a significant deviation from linearity in the backscatter dependence on local incidence angle. The empirical finding may be caused by the microwave scattering dependence on local incidence angle or by the influence of Sentinel-1 SAR sub-swath configuration in the Terrain Observation with Progressive Scans SAR (TOPSAR) method that is used for the measurements.

The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests

Forestry Studies

This work is licensed under the Creative Commons Attribution 4.0 International License.

Pildi alamvälja mõju Sentinel-1 SAR mõõtmiste aegridades

The view angle range of Sentinel-1 SAR in the Interferometric Wide swath (IW) measurement mode is 29.1° – 46.0°. The dependence of backscatter on the arbitrary...

Relative orbit Orbiidi number	θ (deg)	Time, UTC Aeg, UTC	Direction Suund	Images Pilte
058	45.5	16:00	W	254
153	31.3	04:30	E	217
160	39.3	16:00	W	281
080	38.9	04:30	E	281
087	31.7	16:00	W	233
007	45.3	04:30	E	280

The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests

Article Category: Short communication

Pubblicato online: 04 mag 2023

Pagine: 90 - 96

Ricevuto: 19 set 2022

Accettato: 03 ott 2022

DOI: https://doi.org/10.2478/fsmu-2022-0015

Parole chiave
Sentinel-1 SAR, incidence angle, hemiboreal forest, time series, normalization

© 2022 Mait Lang et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1.

Figure 2.

Lisa 1.

Lisa 2.

Sentinel-1 images over Laeva test site. θ is the local incidence angle. Sentinel-1 SAR pildid Laeva testalal. θ on lokaalne langemisnurk.

The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests

Article Category: Short communication

Pubblicato online: 04 mag 2023

Pagine: 90 - 96

Ricevuto: 19 set 2022

Accettato: 03 ott 2022

DOI: https://doi.org/10.2478/fsmu-2022-0015

Parole chiaveSentinel-1 SAR, incidence angle, hemiboreal forest, time series, normalization

© 2022 Mait Lang et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1.

Figure 2.

Lisa 1.

Lisa 2.

Sentinel-1 images over Laeva test site. θ is the local incidence angle. Sentinel-1 SAR pildid Laeva testalal. θ on lokaalne langemisnurk.

Parole chiave
Sentinel-1 SAR, incidence angle, hemiboreal forest, time series, normalization