View source for Tidal Characteristic Numbers of Bed Load Transport

[[category:Tidal Characteristic Numbers]]
[[de: Tidekennwerte des Geschiebetransports]]

[http://www.baw.de/downloads/wasserbau/mathematische_verfahren/pre_postpr/pdf/tdkl-de1.pdf Graphical representation] of characteristic numbers of bedload transport (with German text only). This graphical representation is also available in [http://www.baw.de/downloads/wasserbau/mathematische_verfahren/pre_postpr/eps/tdkl-de2.eps Encapsulated PostScript format]

==Motivation==

The calculation as well as the graphic visualization of various tidal characteristic numbers of [[bed load]] transport contributes to an improved understanding of tidally dominated transport processes in estuaries. Spatial variations of [[bed load]] transport by means of [[flood]] and ebb currents can be highlighted for areas like coastal seas and estuaries.

* The calculated characteristic numbers of [[bed load]] transport do allow for a separation between the amount of [[bed load]] material transported by means of the [[flood]] current as well as by means of the ebb current. Differences in between the two transport rates are mainly due to different hydrodynamic regimes during ebb and [[flood]] tide (e.g. maximum and/or mean current velocity, duration of ebb/flood current).
* The asymmetry between ebb and [[flood]] current transport can be at best demonstrated using the ratio between [[flood]]- and ebb-induced transport rates. But also the calculated residual transport is a good measure for these differences. Zones of convergent or divergent residual transport indicate depositional or erosional areas, whereas zones with a mostly homogeneous residual [[bed load]] transport rate are related to a dynamically stable bed. 

'''An automatic analysis of all tidal characteristic numbers of [[bed load]] transport is carried through by the computer programs [[TDKLF]] and [[NCANALYSE]].'''

==Definitions for the Tidal Characteristic Numbers of Bed Load Transport==

===Program [[NCANALYSE]]===

====Flood Current====

=====Mean Bed Load Transport due to Flood Current=====

Mean value (computed from magnitude) of [[bed load]] transport during [[flood]] current. Vector quantity.
The magnitude corresponds to the mean value computed from the magnitude of all individual vectors (given for different dates).
Mean direction follows from vectorial addition of the individual vectors. <br />
<!-- [[Example figures: mean bed load transport during flood current]]. -->

=====Residual Bed Load Transport due to Flood Current=====

Residual [[bed load]] transport during [[flood]] current. Vector quantity.
Magnitude as well as (mean) direction follow from vectorial addition of the individual vectors (given for different dates).
In case all individual vectors point into the same direction mean and residual value are identical.
The residual can never be larger than the mean value. <br />
<!-- [[Example figures: residual bed load transport during flood current]]. -->

=====Integral Bed Load Transport due to Flood Current=====

Integral (over time) [[bed load]] transport during [[flood]] current. Vector quantity.
Follows from vectorial addition of the individual vectors (given for different dates). <br />
<!-- [[Example figures: integral bed load transport during flood current]]. -->

====Ebb Current====

=====Mean Bed Load Transport due to Ebb Current=====

Mean value (computed from magnitude) of [[bed load]] transport during ebb current. Vector quantity.
The magnitude corresponds to the mean value computed from the magnitude of all individual vectors (given for different dates).
Mean direction follows from vectorial addition of the individual vectors. <br />
<!-- [[Example figures: mean bed load transport during ebb current]]. -->

=====Residual Bed Load Transport due to Ebb Current=====

Residual [[bed load]] transport during ebb current. Vector quantity.
Magnitude as well as (mean) direction follow from vectorial addition of the individual vectors (given for different dates).
In case all individual vectors point into the same direction mean and residual value are identical.
The residual can never be larger than the mean value. <br />
<!-- [[Example figures: residual bed load transport during ebb current]]. -->

=====Integral Bed Load Transport due to Ebb Current=====

Integral (over time) [[bed load]] transport during ebb current. Vector quantity.
Follows from vectorial addition of the individual vectors (given for different dates). <br />
<!-- [[Example figures: integral bed load transport during flood current]]. -->

====Tidal Cycle====

=====Mean Bed Load Transport within a Tidal Cycle=====

Mean value (computed from magnitude) of [[bed load]] transport during a tidal cycle (here this
corresponds to the period between two subsequent ebb slacks). Scalar quantity.
Magnitude corresponds to the mean value computed from the magnitude of all individual vectors (given for different dates).<br />
<!-- [[Example figures: mean bed load transport within a tidal cycle]]. -->

=====Residual Bed Load Transport within a Tidal Cycle=====

Residual (computed from vectorial addition) [[bed load]] transport during a tidal cycle (here this
corresponds to the period between two subsequent ebb slacks). Vector quantity.
Magnitude and direction are computed from vectorial addition of the individual vectors (given for different dates).<br />
<!-- [[Example figures: residual bed load transport within a tidal cycle]]. -->

=====Integral Bed Load Transport within a Tidal Cycle=====

Integral (over time) [[bed load]] transport during a tidal cycle (here this
corresponds to the period between two subsequent ebb slacks). Vector quantity.
Follows from vectorial addition of the individual vectors (given for different dates). <br />
<!-- [[Example figures: integral bed load transport within a tidal cycle]]. -->

=====Ratio of mean Bed Load Transport during Flood Current : mean Bed Load Transport during Ebb Current=====

Quotient computed from the magnitude of mean [[bed load]] transport during [[flood]] current and mean [[bed load]] transport during ebb current.<br />
<!-- [[Example figures: Quotient for mean bed load transport flood current vs. ebb current]]. -->

=====Ratio of mean Bed Load Transport during Flood Current : mean Bed Load Transport during Tidal Cycle=====

Quotient computed from the magnitude of mean [[bed load]] transport during [[flood]] current and mean [[bed load]] transport during the tidal cycle.<br />
<!-- [[Example figures: Quotient for mean bed load transport flood current vs. tidal cycle]]. -->

=====Ratio of mean Bed Load Transport during Ebb Current : mean Bed Load Transport during Tidal Cycle=====

Quotient computed from the magnitude of mean [[bed load]] transport during ebb current and mean [[bed load]] transport during the tidal cycle.<br />
<!-- [[Example figures: Quotient for mean bed load transport ebb current vs. tidal cycle]]. -->

===Program [[TDKLF]]===

====Flood Current====

=====Bed Load Transport due to Flood Current=====

Amount of [[Bed load|Bed Load]] Material which is transported by means of [[flood]] current through a cross section

====Ebb Current====

=====Bed Load Transport due to Ebb Current=====

Amount of [[Bed load|Bed Load]] Material which is transported by means of Ebb Current through a cross section

====Tidal Cycle====

=====Residual Bed Load Transport during a Tidal Cycle=====

Residual amount of [[bed load]] material which is transported by means of ebb and [[flood]] currents through a cross section (the different transport directions are taken into account). If the transport by means of [[flood]] current is equal but in opposite direction of the ebb current transport this will result in a zero advective residual transport of [[bed load]] material.

=====Bed Load Transport, Flood-Ebb-Ratio=====

[[flood]] to ebb ratio for the different amounts of [[bed load]] material which are transported by means of [[flood]] and ebb currents
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