Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level

Climate change and increasing weather and seasonal dynamics challenge agricultural landscapes. To cope with this challenge information on crop performance is key. This study presents a novel framework for bridging landscape-scale vegetation dynamics with field-level crop phenology using Sentinel-1 r...

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Main Authors: Johannes Löw, Steven Hill, Insa Otte, Christoph Friedrich, Michael Thiel, Tobias Ullmann, Christopher Conrad
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-08-01
Series:Frontiers in Remote Sensing
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Online Access:https://www.frontiersin.org/articles/10.3389/frsen.2025.1610005/full
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author Johannes Löw
Steven Hill
Insa Otte
Christoph Friedrich
Michael Thiel
Tobias Ullmann
Christopher Conrad
author_facet Johannes Löw
Steven Hill
Insa Otte
Christoph Friedrich
Michael Thiel
Tobias Ullmann
Christopher Conrad
author_sort Johannes Löw
collection DOAJ
description Climate change and increasing weather and seasonal dynamics challenge agricultural landscapes. To cope with this challenge information on crop performance is key. This study presents a novel framework for bridging landscape-scale vegetation dynamics with field-level crop phenology using Sentinel-1 radar time series. Unlike previous approaches that focus on local algorithm optimisation or SAR feature selection, this work integrates two scales: (1) landscape patterns derived from annual distributions of time series metrics (TSMs) and (2) field-level phenology, both linked to growing degree days (GDD). TSMs were generated through breakpoint analyses over different smoothing intensities for Sentinel-1 polarisation (PolSAR) and interferometric coherence (InSAR) features, capturing crop, orbit and sensor-specific responses. The framework quantifies uncertainties inherent in both remote sensing and ground observations, and evaluates trackable progress (phenological stage detectability) and tracking range (GDD variance around stages) to assess accuracy under variable acquisition geometries, weather and smoothing parameters. Applied to the DEMMIN site (Germany), the analysis revealed consistent TSM-GDD relationships for wheat, rape, and sugar beet, with descriptors such as soil fertility and water availability explaining spatial patterns (R2 ≈ 0.8). Key novelties include the identification of low tracking ranges in drought years, the demonstration of the impact of orbit-specific incidence angles on monitoring fidelity, and the highlighting of Sentinel-1’s ability to resolve phenological variance across fragmented landscapes. By harmonising multi-scale SAR time series with agro-meteorological data, this approach advances transferable methods for operational crop monitoring, supporting precision agriculture and regional yield assessment beyond localised models.
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spelling doaj-art-4b2dfd55cabb4cb3829e46e78749c08b2025-08-25T05:26:27ZengFrontiers Media S.A.Frontiers in Remote Sensing2673-61872025-08-01610.3389/frsen.2025.16100051610005Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field levelJohannes Löw0Steven Hill1Insa Otte2Christoph Friedrich3Michael Thiel4Tobias Ullmann5Christopher Conrad6Department of Geoecology, Martin-Luther-University Halle-Wittenberg, Halle, GermanyEarth Observation Research Cluster, University of Würzburg, Würzburg, GermanyEarth Observation Research Cluster, University of Würzburg, Würzburg, GermanyEarth Observation Research Cluster, University of Würzburg, Würzburg, GermanyEarth Observation Research Cluster, University of Würzburg, Würzburg, GermanyEarth Observation Research Cluster, University of Würzburg, Würzburg, GermanyDepartment of Geoecology, Martin-Luther-University Halle-Wittenberg, Halle, GermanyClimate change and increasing weather and seasonal dynamics challenge agricultural landscapes. To cope with this challenge information on crop performance is key. This study presents a novel framework for bridging landscape-scale vegetation dynamics with field-level crop phenology using Sentinel-1 radar time series. Unlike previous approaches that focus on local algorithm optimisation or SAR feature selection, this work integrates two scales: (1) landscape patterns derived from annual distributions of time series metrics (TSMs) and (2) field-level phenology, both linked to growing degree days (GDD). TSMs were generated through breakpoint analyses over different smoothing intensities for Sentinel-1 polarisation (PolSAR) and interferometric coherence (InSAR) features, capturing crop, orbit and sensor-specific responses. The framework quantifies uncertainties inherent in both remote sensing and ground observations, and evaluates trackable progress (phenological stage detectability) and tracking range (GDD variance around stages) to assess accuracy under variable acquisition geometries, weather and smoothing parameters. Applied to the DEMMIN site (Germany), the analysis revealed consistent TSM-GDD relationships for wheat, rape, and sugar beet, with descriptors such as soil fertility and water availability explaining spatial patterns (R2 ≈ 0.8). Key novelties include the identification of low tracking ranges in drought years, the demonstration of the impact of orbit-specific incidence angles on monitoring fidelity, and the highlighting of Sentinel-1’s ability to resolve phenological variance across fragmented landscapes. By harmonising multi-scale SAR time series with agro-meteorological data, this approach advances transferable methods for operational crop monitoring, supporting precision agriculture and regional yield assessment beyond localised models.https://www.frontiersin.org/articles/10.3389/frsen.2025.1610005/fullSentinel-1phenologyInSAR coherencegrowing degree daysDEMMIN
spellingShingle Johannes Löw
Steven Hill
Insa Otte
Christoph Friedrich
Michael Thiel
Tobias Ullmann
Christopher Conrad
Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
Frontiers in Remote Sensing
Sentinel-1
phenology
InSAR coherence
growing degree days
DEMMIN
title Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
title_full Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
title_fullStr Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
title_full_unstemmed Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
title_short Integrating the landscape scale supports SAR-based detection and assessment of the phenological development at the field level
title_sort integrating the landscape scale supports sar based detection and assessment of the phenological development at the field level
topic Sentinel-1
phenology
InSAR coherence
growing degree days
DEMMIN
url https://www.frontiersin.org/articles/10.3389/frsen.2025.1610005/full
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