Details
Original language | English |
---|---|
Pages (from-to) | 478-489 |
Number of pages | 12 |
Journal | Earth Surface Processes and Landforms |
Volume | 46 |
Issue number | 2 |
Early online date | 28 Nov 2020 |
Publication status | Published - 9 Feb 2021 |
Abstract
Underwater dunes are a morphological feature that are explored by marine scientists and coastal engineers alike. This study presents new methodologies in order to simplify bedform identification and morphodynamic analyses. Specifically, subaqueous compound dunes are decomposed with a simple yet extensive tracking algorithm, which relies on a repeated evaluation of unfiltered bed elevation profiles according to five predefined length classes. In a second step, morphological trends are assessed in the form of bed migration rates, bed slope asymmetries and net sediment changes, in which all parameters are referred to equidistant sections of the examined fairway stretch. This integrated approach not only avoids the challenges in weighting the varying size and abundance of dunes of different scales but also ensures comparability between dune-specific and areal parameters, which significantly improves the interpretation of the morphological setting as a whole. The developed methods are applied to the Outer Jade fairway, an anthropogenically influenced and regularly maintained waterway in the German Bight, and allow scrutiny of spatio-temporal trends in this region. Based on a unique data set of 100 sequential high-quality echo-sounding surveys, various types of bedforms are identified, comprising large-scale primary as well as superimposing secondary dunes that are assumed to interfere with each other. Temporal trends show a long-term rise of the troughs of major bedforms and constant maximum crest elevations near the official maintenance depth, which matches the observed long-term aggradation of sediments. The spatial distribution of integrated morphodynamic parameters reflects a previously described zone of primary dune convergence and facilitates the precise localization of this geophysical singularity. The presented findings both confirm the robustness of the proposed methodologies and, in return, enhance the understanding of morphological processes in the Outer Jade.
Keywords
- German North Sea, Jade fairway, bedform identification, morphodynamics, subaqueous compound dunes
ASJC Scopus subject areas
- Social Sciences(all)
- Geography, Planning and Development
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
- Earth and Planetary Sciences(all)
- Earth and Planetary Sciences (miscellaneous)
Sustainable Development Goals
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In: Earth Surface Processes and Landforms, Vol. 46, No. 2, 09.02.2021, p. 478-489.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Robust methods for the decomposition and interpretation of compound dunes applied to a complex hydromorphological setting
AU - Scheiber, Leon
AU - Lojek, Oliver
AU - Götschenberg, Axel
AU - Visscher, Jan
AU - Schlurmann, Torsten
PY - 2021/2/9
Y1 - 2021/2/9
N2 - Underwater dunes are a morphological feature that are explored by marine scientists and coastal engineers alike. This study presents new methodologies in order to simplify bedform identification and morphodynamic analyses. Specifically, subaqueous compound dunes are decomposed with a simple yet extensive tracking algorithm, which relies on a repeated evaluation of unfiltered bed elevation profiles according to five predefined length classes. In a second step, morphological trends are assessed in the form of bed migration rates, bed slope asymmetries and net sediment changes, in which all parameters are referred to equidistant sections of the examined fairway stretch. This integrated approach not only avoids the challenges in weighting the varying size and abundance of dunes of different scales but also ensures comparability between dune-specific and areal parameters, which significantly improves the interpretation of the morphological setting as a whole. The developed methods are applied to the Outer Jade fairway, an anthropogenically influenced and regularly maintained waterway in the German Bight, and allow scrutiny of spatio-temporal trends in this region. Based on a unique data set of 100 sequential high-quality echo-sounding surveys, various types of bedforms are identified, comprising large-scale primary as well as superimposing secondary dunes that are assumed to interfere with each other. Temporal trends show a long-term rise of the troughs of major bedforms and constant maximum crest elevations near the official maintenance depth, which matches the observed long-term aggradation of sediments. The spatial distribution of integrated morphodynamic parameters reflects a previously described zone of primary dune convergence and facilitates the precise localization of this geophysical singularity. The presented findings both confirm the robustness of the proposed methodologies and, in return, enhance the understanding of morphological processes in the Outer Jade.
AB - Underwater dunes are a morphological feature that are explored by marine scientists and coastal engineers alike. This study presents new methodologies in order to simplify bedform identification and morphodynamic analyses. Specifically, subaqueous compound dunes are decomposed with a simple yet extensive tracking algorithm, which relies on a repeated evaluation of unfiltered bed elevation profiles according to five predefined length classes. In a second step, morphological trends are assessed in the form of bed migration rates, bed slope asymmetries and net sediment changes, in which all parameters are referred to equidistant sections of the examined fairway stretch. This integrated approach not only avoids the challenges in weighting the varying size and abundance of dunes of different scales but also ensures comparability between dune-specific and areal parameters, which significantly improves the interpretation of the morphological setting as a whole. The developed methods are applied to the Outer Jade fairway, an anthropogenically influenced and regularly maintained waterway in the German Bight, and allow scrutiny of spatio-temporal trends in this region. Based on a unique data set of 100 sequential high-quality echo-sounding surveys, various types of bedforms are identified, comprising large-scale primary as well as superimposing secondary dunes that are assumed to interfere with each other. Temporal trends show a long-term rise of the troughs of major bedforms and constant maximum crest elevations near the official maintenance depth, which matches the observed long-term aggradation of sediments. The spatial distribution of integrated morphodynamic parameters reflects a previously described zone of primary dune convergence and facilitates the precise localization of this geophysical singularity. The presented findings both confirm the robustness of the proposed methodologies and, in return, enhance the understanding of morphological processes in the Outer Jade.
KW - German North Sea
KW - Jade fairway
KW - bedform identification
KW - morphodynamics
KW - subaqueous compound dunes
UR - http://www.scopus.com/inward/record.url?scp=85100037139&partnerID=8YFLogxK
U2 - 10.1002/esp.5040
DO - 10.1002/esp.5040
M3 - Article
VL - 46
SP - 478
EP - 489
JO - Earth Surface Processes and Landforms
JF - Earth Surface Processes and Landforms
SN - 0197-9337
IS - 2
ER -