Spoilt for Choice -- When to Use Which Bedform Identification Tool for
What Purpose?
Abstract
Subaqueous dunes are fascinating morphological features that exist in
diverse environments such as the deep sea, continental shelves and
inland streams or rivers. Due to their rhythmic and oftentimes very
frequent occurrence along the predominant flow direction, the analysis
of these bedforms is usually assigned to bedform identification tools.
Such algorithms automatically determine crest and trough locations and
calculate dune dimensions accordingly. Over the last years, the number
of these tools has notably increased with specialized methodologies for
every environment and bedform scale. Although many of them are readily
available to interested researchers, there may be uncertainty as to
which method should be applied in view of a specific research question.
As authors of some of the most recent bedform identification tools, we
have started to systematically compare our approaches by analyzing an
agreed set of diverse bathymetric data. The bed features assessed in
this context range from river dunes formed under unidirectional flow
over tidally constrained compound dunes to bed elevation profiles gained
from flume experiments. The resulting dune characteristics, which each
scientist obtained by applying his/her particular algorithm, are
thereupon contrasted in a qualitative and quantitative manner uncovering
the similarities and differences between individual methodologies. Our
preliminary results suggest a strong influence of the original focus of
each algorithm and therefore corroborate the need for systematic
comparison. In the next step, the gained insights will be used to find
and explain the optimum fields of application and, in the end, provide
user-oriented guidelines that may support the bedform community in
deciding which identification tool should be used for what purpose.