20100414 Herman Ridderinkhof Zeeonderzoek Aan Boord


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20100414 Herman Ridderinkhof Zeeonderzoek Aan Boord

  1. 1. Royal Netherlands Institute for Sea Research Sea research on board the clipper Stad Amsterdam with a focus on ocean currents and the role of the ocean in the climate system Prof. dr. ir. Herman Ridderinkhof NIOZ is part of the Netherlands Organisation for Scientific Research (NWO) 1
  2. 2. Our planet is blue and should not be called ‘earth’ but ‘ocean’ Measurements in the NIOZ database 2
  3. 3. Pelagia: the research vessel that is used by the Netherlands to study the oceans 3
  4. 4. Oceanographers participate in many trajects of the Beagle voyage
  5. 5. Daily observations on board the clipper Watersamples (in -80 freezer) •Nutrients (P,N,Si) •Viruses •Bacteria •Plankton Sensor observations (CTD behind the clipper) •Temperature •Salinity •Fluorescence •transmission 5
  6. 6. More than one million virusses per milliliter seawater…. Daily about 1023 infections in the ocean! …but what are the consequences for the functioning of the marine foodweb? 6
  7. 7. The ocean is a very important component of the earth climate system  The ocean takes up CO2 from the atmosphere  The ocean has a very large capacity to store heat and thereby functions as a ‘memory’ for the atmosphere (and our daily weather)  Ocean currents redistribute heat over the planet
  8. 8. Surface circulation in the upper part of the North Atlantic Ocean Due to the northward heat transport and the westerly winds the climate in western Europe is about 5 degrees warmer than at a similar latitude in Norht America
  9. 9. El Nino: a natural oscillating climate phenomenon with large societal consequences
  10. 10. The average currents at the ocean surface are known for centuries (discovered and described by seaman) Knowledge on theGulf Stream has been used for navigational purposes since the times of Columbus
  11. 11. A regular windfield causes a regular pattern of surface currents: the big surface gyres in all oceans; currents deduced from observations from ships (dead reckoning)
  12. 12. Satellite picture of ocean temperature: the influence of the ocean gyres in redistributing heat is clearly visible
  13. 13. What happens in the deep sea? First observations with German RV Meteor
  14. 14. Global overturning circulation with warm surface currents and cold bottom currents This overturning circulation connects all oceans and is driven by density differences 14
  15. 15. The conveyor belt: a cartoon of the global 3D overturning deep sea circulation
  16. 16. Climate change by changing ocean currents inspires the media, and even Hollywood…..
  17. 17. The Netherlands participates in global research programs on the ocean circulation Long term observations with deep sea moorings; part of the international program OceanSITES; focus on long term variability 17
  18. 18. Measurements on currents, temperature, salinity in the Indian Ocean (2000-2012) Long term moorings in the Mozambique Channel 18
  19. 19. Results of NIOZ-Utrecht University study •No continuous boundary current (currents on nautical charts (and the Bosatlas!) are wrong) •Ocean eddies dominate •Mozambique eddies influence the Agulhas current and thereby the exchange between the Indian and Atlantic ocean •Strong year to year variability 19
  20. 20. •International research with participation of different disciplines •Physical Oceanography •Modelling •Geology 20
  21. 21. Recent knowledge: the ocean is full of eddies that dominate the actual currents Light reflection by plankton Temperature near Californië Chlorophyl near Australië
  22. 22. Satellite measurements on the height of the sea surface •Red: higher sea surface •Blue: lower sea surface 22
  23. 23. Actual ocean currents can be used in planning the route of ships (also on the clipper Stad Amsterdam??) 23
  24. 24. Oceans are characterized by their, unobserved, large spatial variability Recent observations from the CTD on the temperature clipper, Sunday 11 april Showing •Strong increase in temperature (4 degrees) •Strong decrease in chlorophyll chlorophyll 24
  25. 25. Oceans are characterized by their, unobserved, large spatial variability Route of the clipper on Sunday 11 april 25
  26. 26. Satellite observations on chlorophyll and sea surface temperature also show large variability Sea surface temperature 12 april 2010 26
  27. 27. Satellite observations on chlorophyll and sea surface temperature also show large variability Chlorophyll 12 april 2010 27
  28. 28. Oceans are very variable! Eddies and currents in the ocean are similar to high (low) pressure and wind in the atmosphere Ocean current predictions will become similar to weather predictions Tropical cyclone Hudah, Mozambique Channel, 2000