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

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 th...

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Main Authors: Lang Mait, Praks Jaan
Format: Article
Language:English
Published: Sciendo 2022-12-01
Series:Metsanduslikud Uurimused
Subjects:
Online Access:https://doi.org/10.2478/fsmu-2022-0015
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author Lang Mait
Praks Jaan
author_facet Lang Mait
Praks Jaan
author_sort Lang Mait
collection DOAJ
description 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.
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spelling doaj.art-fa0048cc2ede4f9593c62ad1ad7340562023-05-29T10:56:30ZengSciendoMetsanduslikud Uurimused1736-87232022-12-01771909610.2478/fsmu-2022-0015The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forestsLang Mait0Praks Jaan11Tartu Observatory, University of Tartu, 61602Tõravere, Tartumaa, Estonia;3Department of Radio Science and Engineering, Aalto University, P.O. Box 13000, 00076Aalto, Finland;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.https://doi.org/10.2478/fsmu-2022-0015sentinel-1 sarincidence anglehemiboreal foresttime seriesnormalization
spellingShingle Lang Mait
Praks Jaan
The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
Metsanduslikud Uurimused
sentinel-1 sar
incidence angle
hemiboreal forest
time series
normalization
title The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
title_full The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
title_fullStr The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
title_full_unstemmed The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
title_short The influence of Sentinel-1 SAR sub-swath on the recorded backscatter time-series over managed hemiboreal forests
title_sort influence of sentinel 1 sar sub swath on the recorded backscatter time series over managed hemiboreal forests
topic sentinel-1 sar
incidence angle
hemiboreal forest
time series
normalization
url https://doi.org/10.2478/fsmu-2022-0015
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