Die  Küste,  81  (2014),  369-392

389

Figure  19:  Net  sediment  deposition  integrated  over  the  boundary  of  the  German  Bight  derived
from  UnTRIM  (red),  TELEMAC  (green)  and  MARINA  (light  blue)  and  duration  of  high  wind
(>  18  m/s)  at  Elelgoland  —  control  sections  for  balancing  are  marked  in  the  right  panel.

The  highest  net  deposition  quantity  of  die  investigated  yearly  simulations  is  42  Mtyr 1 .
This  amount  is  only  reproduced  in  other  years  toal/2orl/3  amount.  The  comparison
of  the  different  model  results  shows  e.g.  for  die  year  1998  a  relatively  good  agreement
(40.5  -  46.5  Mtyr 1 ).  In  2006  die  difference  is  distinct  (30  Mt/a  -  44  Mtyr 1 ).
The  comparison  witii  die  duration  of  high  wind  speed  shows  a  predominantly  large
correlation  witii  die  net  deposition  quantity.  This  suggests  tiiat  meteorological  forcing  has
a  strong  effect  in  relation  to  the  magnitude  and  direction  of  die  residual  velocities  /
transport  in  die  German  Bight.
The  deptii  variable  distribution  of  die  net  transport  mass  is  of  special  interest.
Detailed  analyses  show  tiiat  a  predominant  portion  is  transported  in  a  deptii  range  of
between  10  -  20  m.  The  transport  rates  behind  die  East  Frisian  Islands,  on  the  wadden
area  towards  die  coast,  are  noticeably  smaller.

7  Conclusion
There  are  many  reasons  why  the  assessment  of  morphological  conditions  in  the  German
Bight  is  associated  with  great  uncertainties.  The  measuring  techniques  and  field  data  in
themselves  fail  to  provide  a  reasonably  sufficient  level  of  accuracy.  Of  course,  all  models
are  based  on  numerous  simplifications,  and  simulation  models  as  such  are  also  restricted
due  to  die  numerical  approximation  of  physics  and  die  limitations  (construction,  evolution ­
  ...)  of  computer  systems.
It  will  only  be  possible  to  obtain  greater  confidence  concerning  die  reproduction,
analysis  and  prediction  of  sediment  transport  and  morphodynamics  in  die  German  Bight
within  a  multidisciplinary  approach.  This  integrated  concept  provides  a  broad  consistent
dataset  for  future  analyses  and  numeric  modelling  of  morphodynamic  processes  in  the
German  Bight.
Uncertainty  can  be  reduced  by  adopting  a  multi-model  approach  to  data  and  process
based  simulation  models.  The  application  of  different  spatial  and  temporal  model  improvements, ­
  as  well  as  miscellaneous  physical  approximations  in  different  modelling  systems, ­
  will  also  improve  the  accuracy  of  the  overall  findings.
The  process-based  modelling  approach  enables  large  area  circulation  and  sediment
transport  processes  in  the  entire  German  Bight  to  be  simulated  and  analyzed.  This  is