Meten meten meten, denken denken denken, schrijven schrijven schrijven, reviewen, reviewen reviewen, schrijven schrijven schrijven (doet met inmiddels aan Monty Python denken).
En de krant pikt dit stukje op, maar ik heb inmiddels de site van die conferentie gevonden en als je de abstract van het praatje van Byrden leest hebben ze het nergens over een 10 daags stilvallen van de stroom. Voor hun is het waarschijnlijk niet meer dan een opvallend punt uit een breder onderzoek.
Er staat wel een ander abstract dat het heeft over het plotseling wijzigen van de stroom.
Abstract:
Variability in the Atlantic meridional overturning circulation at 25°N
Harry L. Bryden1, Torsten O. Kanzow1, Hannah R. Longworth1, Stuart A. Cunningham1, Molly O. Baringer2, Lisa M. Beal3, Joel J.- M Hirschi1, William E. Johns3, Christopher S. Meinen2, Jochem Marotzke4, Darren Rayner1
1) National Oceanography Centre, Southampton, U.K.
2) NOAA/Atlantic Oceanographic and Meteorological Laboratory, U.S.A.
3) Rosenstiel School of Marine and Atmospheric Science, University of Miami, U.S.A.
4) Max Planck Institute for Meteorolgoy, Hamburg, Germany
Since Spring 2004, the Rapid monitoring array along 25°N has continuously measured the Atlantic meridional overturning circulation (MOC) in the subtropical North Atlantic. The basin-scale monitoring system includes top-to-bottom temperature and salinity and bottom pressure measurements off the Bahamas, south of the Canaries and at either side of the Mid-Atlantic Ridge to define the full depth, basinscale mid-ocean geostrophic circulation on a daily basis. Combining the mid-ocean geostrophic circulation with continuous electromagnetic cable measurements of the Gulf Stream flow through Straits of Florida and with wind-driven Ekman surface layer transport from NCEP, SOC and QuikScat climatologies, we can estimate the size of the overturning circulation on a daily basis. We use the first year of Rapid monitoring measurements from March 2004 to April 2005 to define the subannual variability in the mid-ocean geostrophic circulation for the first time. We then combine the mid-ocean circulation with Gulf Stream and Ekman transport to define the variability in the overturning circulation at 25°N. Finally we examine historical hydrographic stations near the Rapid moorings at the eastern and western boundaries of the section to assess the interannual variability in the mid-ocean circulation and overturning. Transport anomalies of the upper waters and NADW computed from these historical stations suggest that the interannual variability between 1980 and 2005 is not significantly greater than the variability observed from the first year of Rapid monitoring.
Treating the Rapid observations as a continuous hydrographic section, we first estimate the temporal variability in the mid-ocean baroclinic circulation where the overall mid-ocean geostrophic transport is set to a constant annual average value representing the annual average Gulf Stream plus Ekman transport. The standard deviation in upper or lower layer transports is less than 3 Sv, half as large as previous estimates of baroclinic variability made by Ganachaud (2003). The year-long average layer transports are similar to those estimated for the April-May 2004 transatlantic hydrographic section but indicate a slightly larger overturning than the section estimate.
Bottom pressure records show surprising coherence at low-frequency time scales: to first order, bottom pressures everywhere along the 25°N section go up and down together. Zonal differences in bottom pressure do occur between the eastern and western basins and across the western basin and we use these bottom pressure differences to define an "external" mode of geostrophic variability. The "internal" mode is defined to be the baroclinic geostrophic flow referenced to the bottom which is determined from the top-to-bottom temperature and salinity measurements. The external and internal modes exhibit significant anti-correlation and there is strong compensation between them. Furthermore, the sum of the internal and external mode transports is anti-correlated to Gulf Stream and Ekman transport variability so that the four modes largely compensate to ensure mass balance on periods longer than two weeks.
En de krant pikt dit stukje op, maar ik heb inmiddels de site van die conferentie gevonden en als je de abstract van het praatje van Byrden leest hebben ze het nergens over een 10 daags stilvallen van de stroom. Voor hun is het waarschijnlijk niet meer dan een opvallend punt uit een breder onderzoek.
Er staat wel een ander abstract dat het heeft over het plotseling wijzigen van de stroom.
Abstract:
Variability in the Atlantic meridional overturning circulation at 25°N
Harry L. Bryden1, Torsten O. Kanzow1, Hannah R. Longworth1, Stuart A. Cunningham1, Molly O. Baringer2, Lisa M. Beal3, Joel J.- M Hirschi1, William E. Johns3, Christopher S. Meinen2, Jochem Marotzke4, Darren Rayner1
1) National Oceanography Centre, Southampton, U.K.
2) NOAA/Atlantic Oceanographic and Meteorological Laboratory, U.S.A.
3) Rosenstiel School of Marine and Atmospheric Science, University of Miami, U.S.A.
4) Max Planck Institute for Meteorolgoy, Hamburg, Germany
Since Spring 2004, the Rapid monitoring array along 25°N has continuously measured the Atlantic meridional overturning circulation (MOC) in the subtropical North Atlantic. The basin-scale monitoring system includes top-to-bottom temperature and salinity and bottom pressure measurements off the Bahamas, south of the Canaries and at either side of the Mid-Atlantic Ridge to define the full depth, basinscale mid-ocean geostrophic circulation on a daily basis. Combining the mid-ocean geostrophic circulation with continuous electromagnetic cable measurements of the Gulf Stream flow through Straits of Florida and with wind-driven Ekman surface layer transport from NCEP, SOC and QuikScat climatologies, we can estimate the size of the overturning circulation on a daily basis. We use the first year of Rapid monitoring measurements from March 2004 to April 2005 to define the subannual variability in the mid-ocean geostrophic circulation for the first time. We then combine the mid-ocean circulation with Gulf Stream and Ekman transport to define the variability in the overturning circulation at 25°N. Finally we examine historical hydrographic stations near the Rapid moorings at the eastern and western boundaries of the section to assess the interannual variability in the mid-ocean circulation and overturning. Transport anomalies of the upper waters and NADW computed from these historical stations suggest that the interannual variability between 1980 and 2005 is not significantly greater than the variability observed from the first year of Rapid monitoring.
Treating the Rapid observations as a continuous hydrographic section, we first estimate the temporal variability in the mid-ocean baroclinic circulation where the overall mid-ocean geostrophic transport is set to a constant annual average value representing the annual average Gulf Stream plus Ekman transport. The standard deviation in upper or lower layer transports is less than 3 Sv, half as large as previous estimates of baroclinic variability made by Ganachaud (2003). The year-long average layer transports are similar to those estimated for the April-May 2004 transatlantic hydrographic section but indicate a slightly larger overturning than the section estimate.
Bottom pressure records show surprising coherence at low-frequency time scales: to first order, bottom pressures everywhere along the 25°N section go up and down together. Zonal differences in bottom pressure do occur between the eastern and western basins and across the western basin and we use these bottom pressure differences to define an "external" mode of geostrophic variability. The "internal" mode is defined to be the baroclinic geostrophic flow referenced to the bottom which is determined from the top-to-bottom temperature and salinity measurements. The external and internal modes exhibit significant anti-correlation and there is strong compensation between them. Furthermore, the sum of the internal and external mode transports is anti-correlated to Gulf Stream and Ekman transport variability so that the four modes largely compensate to ensure mass balance on periods longer than two weeks.
Karma police arrest this man, he talks in math...
.