Royal Netherlands Institute for Sea Research
1
Tides and shallow water sea research at NIOZ
Royal Netherlands Institute fo...
Crossing the Agulhas current
2
Sea surface temperature
3
Chlorophyll
Crossing the Agulhas current
4
Temperature from CTD behind the clipper
Crossing the Agulhas current
18 april
19 april till
09.00
5
Crossing the Agulhas current
Tides
Herman Ridderinkhof
NIOZ and Utrecht University
 What are the causes of tides and what are their characteristics?
...
Daily
inequality
delay: moon phases - tidal phenomena
Neap tide
Spring tide
Two highs and
lows per day
General pattern of ...
Examples:
“Lunar” frequencies
- lunar day
- 2 x lunar day (dominant)
- overtones
- eccentricity lunar orbit
- tilt lunar o...
Astronomical forces
Tides are caused by the gravitational force of
the moon and sun and the motion of the earth-
moon-sun...
Tidal frequencies: lunar day
A lunar day is the time that elapses between
when the moon is directly overhead and the
next...
Tidal frequencies: spring-neap
variability
There are lots of other “astronomical frequencies” :
example: relative tilts of plane of the Moon’s orbit and equator plan...
© 2002 Brooks/Cole, a division of Thomson Learning, Inc.
Amplitudes of tidal component can differ
enormously at different ...
Tide Patterns
The worldwide distribution of the three tidal patterns.
 Tide driven by astronomical forces is present only in the Southern
Ocean.
 Amplitude of tide due to astronomical force,...
 How do tides propagate in oceans and shelf seas?
William Thomson
(Lord Kelvin) Sea level displacement for a
Kelvin wave
Kelvin wave in a
square tank:
The Coriolis force
lets the wave run
along the wall on the
right side (northern
hemisphere)
Amplitudes and phase lines from a world ocean tidal
model
The Kelvin waves in the
Atlantic Ocean start in
the south
For the tidal wave
it takes about 2-2.5
days to move from
the So...
Kelvin waves in the
North Sea
split up in
three separate
Kelvin waves
The “Knots”
are called
Amphidromic
points. Here is n...
Resonance occurs if reflected wave from landward end amplifies the
incoming wave (length basin = .5 * tidal wave length)
T...
The largest tidal range in
the world occurs in Nova
Scotia's Bay of Fundy. Even
though the maximum spring
tidal range at t...
 Bay of Fundy, High Tide
Bay of Fundy, Low Tide 
Kelvin wave along Dutch
coast
Near-resonance in Wadden
Sea combined with strong
bottom friction
Tides in Wadden Sea have
become stronger due to
closure ...
 Tide is excited by astronomical forces. ‘Ideal tide’ is present only
in the Southern Ocean (no continents).
 Frequencie...
29
Some NIOZ Wadden Sea studies based on
our speciality: observations at sea
‘Navicula’ ‘Stern’ (Tern) Flatboat ’t Horntje...
Continuous (sensor based) observationsContinuous (sensor based) observations
ferry
jetty
Ferry observations since 1998
water
Slib
Netto fluxen
water: naar
Noordzee
slib: naar
Waddenzee
(veel groter dan
eerdere
schattingen, nu als
T0 meting i...
Bottom depth of
the Marsdiep inlet,
and the changes
over time showing
migrating
sandwaves
A
Cross section of the bottom profile along section A
Migrating sandwaves into the WaddenSea with a
height of 2-3 m and a ...
B
Cross section of the bottom profile along section B
Migrating sandwaves into the WaddenSea with a
height of 7-8 m and a ...
1 8 6 0 1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0
Y e a r
8
9
1 0
1 1
1 2
1 3
Temperature(oC)
M a r s d ie p...
Into the field
Predicted intake rate of the knot (time-
series since 1991)
1970 1977 1984 1991 1998 2005
-2
-1
0
1
2
3
Standardisedunits(-)
Estuarine birds (PC2; following winter)
Macrozoobenthos (...
December
November
October
September
August
July
June
May
April
March
February
January 1975 1980 1985 1990 1995 2000 2005
P...
Wadden Sea Observatory (2010 onward)
Sensorobservations from
•Exisitng platforms
•New poles
Field surveys (e.g. benthos)
20100418_Herman_Ridderinkhof_Getijden
20100418_Herman_Ridderinkhof_Getijden
Upcoming SlideShare
Loading in …5
×

20100418_Herman_Ridderinkhof_Getijden

712 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
712
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
0
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

20100418_Herman_Ridderinkhof_Getijden

  1. 1. Royal Netherlands Institute for Sea Research 1 Tides and shallow water sea research at NIOZ Royal Netherlands Institute for Sea Research but first: crossing the Agulhas current NIOZ is part of the Netherlands Organisation for Scientific Research (NWO) Herman Ridderinkhof
  2. 2. Crossing the Agulhas current 2 Sea surface temperature
  3. 3. 3 Chlorophyll Crossing the Agulhas current
  4. 4. 4 Temperature from CTD behind the clipper Crossing the Agulhas current 18 april 19 april till 09.00
  5. 5. 5 Crossing the Agulhas current
  6. 6. Tides Herman Ridderinkhof NIOZ and Utrecht University  What are the causes of tides and what are their characteristics?  How do tides propagate in oceans (e.g. Atlantic), shelf seas (e.g. North Sea), shallow tidal basins (e.g. Wadden Sea)?
  7. 7. Daily inequality delay: moon phases - tidal phenomena Neap tide Spring tide Two highs and lows per day General pattern of the vertical tide at one station
  8. 8. Examples: “Lunar” frequencies - lunar day - 2 x lunar day (dominant) - overtones - eccentricity lunar orbit - tilt lunar orbit - etc... “Solar” frequencies - similar to moon freq. And all kinds of crossterms A tidal signal can be decomposed in a number of frequencies related to astronomical frequencies
  9. 9. Astronomical forces Tides are caused by the gravitational force of the moon and sun and the motion of the earth- moon-sun system The gravitational force causes a deformation of the ocean surface (equilibrium tide) Frequencies of planetary motions result in different ‘astronomical frequencies’
  10. 10. Tidal frequencies: lunar day A lunar day is the time that elapses between when the moon is directly overhead and the next time the moon is directly overhead. During one complete rotation of Earth (the 24- hour solar day) the moon moves eastward 12.2 degrees, and Earth must rotate an additional 50 minutes to place the moon in the exact same position overhead. Thus, a lunar day is 24 hours 50 minutes long (and a solar day 24 hours).
  11. 11. Tidal frequencies: spring-neap variability
  12. 12. There are lots of other “astronomical frequencies” : example: relative tilts of plane of the Moon’s orbit and equator plane. These variations are a.o. recognizable in geology.
  13. 13. © 2002 Brooks/Cole, a division of Thomson Learning, Inc. Amplitudes of tidal component can differ enormously at different locations Tide curves for three common types of tides.
  14. 14. Tide Patterns The worldwide distribution of the three tidal patterns.
  15. 15.  Tide driven by astronomical forces is present only in the Southern Ocean.  Amplitude of tide due to astronomical force, the equilibrium tide, is 0.27 m due to the moon and 0.12 m due to the sun  Tides at any location outside the Southern Ocean are caused by propagation of the tidal wave from the Southern Ocean
  16. 16.  How do tides propagate in oceans and shelf seas? William Thomson (Lord Kelvin) Sea level displacement for a Kelvin wave
  17. 17. Kelvin wave in a square tank: The Coriolis force lets the wave run along the wall on the right side (northern hemisphere)
  18. 18. Amplitudes and phase lines from a world ocean tidal model
  19. 19. The Kelvin waves in the Atlantic Ocean start in the south For the tidal wave it takes about 2-2.5 days to move from the Southern Ocean to the North Sea (spring tide is 2-2.5 after full moon)
  20. 20. Kelvin waves in the North Sea split up in three separate Kelvin waves The “Knots” are called Amphidromic points. Here is no vertical tide
  21. 21. Resonance occurs if reflected wave from landward end amplifies the incoming wave (length basin = .5 * tidal wave length) Tides in Confined Basins: no Kelvin wave but possibility of amplification due to resonance
  22. 22. The largest tidal range in the world occurs in Nova Scotia's Bay of Fundy. Even though the maximum spring tidal range at the mouth of the bay is only 2 meters, amplification of tidal energy causes a maximum tidal range at the northern end of Minas Basin of 17 meters.
  23. 23.  Bay of Fundy, High Tide Bay of Fundy, Low Tide 
  24. 24. Kelvin wave along Dutch coast
  25. 25. Near-resonance in Wadden Sea combined with strong bottom friction Tides in Wadden Sea have become stronger due to closure with Afsluitdijk!
  26. 26.  Tide is excited by astronomical forces. ‘Ideal tide’ is present only in the Southern Ocean (no continents).  Frequencies of the tide are related to astronomical frequencies  Tides propagate through the world oceans as rotating (Kelvin) waves  Amplitude of the tide at a certain location strongly depends on the resonance characteristics of a sea basin Tides: important issues
  27. 27. 29 Some NIOZ Wadden Sea studies based on our speciality: observations at sea ‘Navicula’ ‘Stern’ (Tern) Flatboat ’t Horntje’  Ferry based observations and studies  Ecological studies based on (long term) field observations
  28. 28. Continuous (sensor based) observationsContinuous (sensor based) observations ferry jetty
  29. 29. Ferry observations since 1998
  30. 30. water Slib Netto fluxen water: naar Noordzee slib: naar Waddenzee (veel groter dan eerdere schattingen, nu als T0 meting ivm Maasvlakte-II aanleg)
  31. 31. Bottom depth of the Marsdiep inlet, and the changes over time showing migrating sandwaves
  32. 32. A Cross section of the bottom profile along section A Migrating sandwaves into the WaddenSea with a height of 2-3 m and a length of 100 m (dark is orinigal profile)
  33. 33. B Cross section of the bottom profile along section B Migrating sandwaves into the WaddenSea with a height of 7-8 m and a length of 300 m (dark is orinigal profile)
  34. 34. 1 8 6 0 1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0 Y e a r 8 9 1 0 1 1 1 2 1 3 Temperature(oC) M a r s d ie p A n n u a l m e a n t e m p e r a t u r e s in c e 1 8 6 1 1 8 6 0 1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0 Y e a r 2 6 2 8 3 0 3 2 3 4 Salinity M a r s d ie p A n n u a l m e a n s a lin it y s in c e 1 8 6 1 Temperature, Salinity since 1861 (van Aken) Now from NIOZ jetty
  35. 35. Into the field
  36. 36. Predicted intake rate of the knot (time- series since 1991)
  37. 37. 1970 1977 1984 1991 1998 2005 -2 -1 0 1 2 3 Standardisedunits(-) Estuarine birds (PC2; following winter) Macrozoobenthos (PC1; following winter) Phytoplankton (PC2; summer) Concurrent changes Wadden Sea communities Phosphate concentrations early spring Nutrient enrichment & reduction Phytoplankton NIOZ Macrozoobenthos NIOZ/RWS Estuarine birds SOVON Philippart et al. (under review) Ecosystems Observation : Correlation : Possible Cause :
  38. 38. December November October September August July June May April March February January 1975 1980 1985 1990 1995 2000 2005 Philippart & Peperzak (2006) Waddenbulletin < 1000 cells/ml > 1000 cells/ml Observation : Correlation : Possible Cause : Variations in seasonality Phaeocystis blooms Nutrients and/or climate change? Phaeocystis globosa
  39. 39. Wadden Sea Observatory (2010 onward) Sensorobservations from •Exisitng platforms •New poles Field surveys (e.g. benthos)

×