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depth and dissipation in the shallow seas; Egbert et al. (2004) estimate that the North Atlantic tides during glacial times were 2 times as high and the pelagic dissipation almost three times the present rate. These feedbacks dwarf the astronomic forcing. But the numbers will not go away. It takes 10 25 J to melt enough ice to raise the sea level by 120 m. This corresponds to only 300 yr of the 10 15 W flux. A 3% increase in the MOC heat flux could account for the entire melting. Acknowledgments
depth and dissipation in the shallow seas; Egbert et al. (2004) estimate that the North Atlantic tides during glacial times were 2 times as high and the pelagic dissipation almost three times the present rate. These feedbacks dwarf the astronomic forcing. But the numbers will not go away. It takes 10 25 J to melt enough ice to raise the sea level by 120 m. This corresponds to only 300 yr of the 10 15 W flux. A 3% increase in the MOC heat flux could account for the entire melting. Acknowledgments
equation of state). Global sea level rises when the absolute mass of the ocean water is increased (eustatic sources), through variations of the global mean salinity (which depends on eustatic sources, with the exception of melting sea ice), or when the specific volume is modified through net heating or cooling. The ocean heat content would change as a result of a planetary energy imbalance ( Levitus et al. 2000 ). The issue of global sea level rise has received considerable attention in the last decade
equation of state). Global sea level rises when the absolute mass of the ocean water is increased (eustatic sources), through variations of the global mean salinity (which depends on eustatic sources, with the exception of melting sea ice), or when the specific volume is modified through net heating or cooling. The ocean heat content would change as a result of a planetary energy imbalance ( Levitus et al. 2000 ). The issue of global sea level rise has received considerable attention in the last decade
Circulation and Climate: Observing and Modeling the Global Ocean, G. Siedler, J. Church, and J. Gould, Eds., International Geophysics Series, Vol. 77, Academic Press, 455–474 . Cazenave , A. , and R. S. Nerem , 2004 : Present-day sea level change: Observations and causes. Rev. Geophys. , 42 . RG3001, doi:10.1029/2003RG000139 . Cazenave , A. , F. Remy , K. Dominh , and H. Douville , 2000 : Global ocean mass variations, continental hydrology and the mass balance of the Antarctica ice
Circulation and Climate: Observing and Modeling the Global Ocean, G. Siedler, J. Church, and J. Gould, Eds., International Geophysics Series, Vol. 77, Academic Press, 455–474 . Cazenave , A. , and R. S. Nerem , 2004 : Present-day sea level change: Observations and causes. Rev. Geophys. , 42 . RG3001, doi:10.1029/2003RG000139 . Cazenave , A. , F. Remy , K. Dominh , and H. Douville , 2000 : Global ocean mass variations, continental hydrology and the mass balance of the Antarctica ice
. Tokmakian , and K. J. Heywood , 2001 : Antarctic Circumpolar Current response to zonally averaged winds. J. Geophys. Res. , 106 , 2743 – 2759 . Greatbatch , R. J. , Y. Lu , and Y. Cai , 2001 : Relaxing the Boussinesq approximation in ocean circulation models. J. Atmos. Oceanic Technol. , 18 , 1911 – 1923 . Hall , A. , and M. Visbeck , 2002 : Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the annular mode. J. Climate , 15
. Tokmakian , and K. J. Heywood , 2001 : Antarctic Circumpolar Current response to zonally averaged winds. J. Geophys. Res. , 106 , 2743 – 2759 . Greatbatch , R. J. , Y. Lu , and Y. Cai , 2001 : Relaxing the Boussinesq approximation in ocean circulation models. J. Atmos. Oceanic Technol. , 18 , 1911 – 1923 . Hall , A. , and M. Visbeck , 2002 : Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the annular mode. J. Climate , 15
stress curl east of New Zealand. 6. Secular heat content changes For climate applications, our knowledge of the connection between the changing atmospheric forcing and changes in the deep ocean over hundreds of years is rudimentary. In this discussion, changes in the ocean’s inventory of heat, salt, mass, and sea level are all relevant, as is ice melting. We will use in the following the model’s results to compute changes in the global model heat and salt content. Shown in Fig. 12 are time series
stress curl east of New Zealand. 6. Secular heat content changes For climate applications, our knowledge of the connection between the changing atmospheric forcing and changes in the deep ocean over hundreds of years is rudimentary. In this discussion, changes in the ocean’s inventory of heat, salt, mass, and sea level are all relevant, as is ice melting. We will use in the following the model’s results to compute changes in the global model heat and salt content. Shown in Fig. 12 are time series
: Intermediate-depth circulation of the Indian and South Pacific Oceans measured by autonomous floats. J. Phys. Oceanogr. , 35 , 683 – 707 . Ducet , N. , P-Y. Le Traon , and G. Reverdin , 2000 : Global high resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2 . J. Geophys. Res. , 105 , 19477 – 19498 . Hall , A. , and M. Visbeck , 2002 : Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the annular mode. J
: Intermediate-depth circulation of the Indian and South Pacific Oceans measured by autonomous floats. J. Phys. Oceanogr. , 35 , 683 – 707 . Ducet , N. , P-Y. Le Traon , and G. Reverdin , 2000 : Global high resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2 . J. Geophys. Res. , 105 , 19477 – 19498 . Hall , A. , and M. Visbeck , 2002 : Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the annular mode. J
western North Atlantic Ocean. Geophys. Res. Lett. , 29 . 2227, doi:10.1029/2002GL015618 . Foldvik , A. , and Coauthors , 2004 : Ice shelf water overflow and bottom water formation in the southern Weddell Sea. J. Geophys. Res. , 109 . C02015, doi:10.1029/2003JC002008 . Fukasawa , M. , H. Freeland , R. Perkin , T. Watanabe , H. Uchida , and A. Nishina , 2004 : Bottom water warming in the North Pacific Ocean. Nature , 428 , 825 – 827 . Ganachaud , A. , and C. Wunsch
western North Atlantic Ocean. Geophys. Res. Lett. , 29 . 2227, doi:10.1029/2002GL015618 . Foldvik , A. , and Coauthors , 2004 : Ice shelf water overflow and bottom water formation in the southern Weddell Sea. J. Geophys. Res. , 109 . C02015, doi:10.1029/2003JC002008 . Fukasawa , M. , H. Freeland , R. Perkin , T. Watanabe , H. Uchida , and A. Nishina , 2004 : Bottom water warming in the North Pacific Ocean. Nature , 428 , 825 – 827 . Ganachaud , A. , and C. Wunsch
and PF. The southern- and northernmost features (Bdy and SAZ) coincide with less than 70% of the high SSH gradients in their SSH range. SSH gradients in both regions are relatively weak. In addition, the Bdy front is close to the Antarctic continental margin where the SSH satellite observations are most affected by sea ice cover. The weak gradient extrema in the SAZ do not correspond to either the SAF or the subtropical front (STF) and are not as well described by a single SSH value, as discussed
and PF. The southern- and northernmost features (Bdy and SAZ) coincide with less than 70% of the high SSH gradients in their SSH range. SSH gradients in both regions are relatively weak. In addition, the Bdy front is close to the Antarctic continental margin where the SSH satellite observations are most affected by sea ice cover. The weak gradient extrema in the SAZ do not correspond to either the SAF or the subtropical front (STF) and are not as well described by a single SSH value, as discussed
, increasing the eastward transport to 2.2 Sv at 146°E. There is a westward-flowing boundary current against the Antarctic continent south of the Antarctic slope front (ASF), particularly in the presence of the Ross and Weddell Sea gyres, where flow approaches 60 Sv. These gyres are possibly overestimated in this study, in comparison with Semtner and Chervin’s (1992) record of around 30 Sv, because of the lack of sea ice in the model and winter wind bias. The 29.4 ± 14.7 Sv Antarctic coastal
, increasing the eastward transport to 2.2 Sv at 146°E. There is a westward-flowing boundary current against the Antarctic continent south of the Antarctic slope front (ASF), particularly in the presence of the Ross and Weddell Sea gyres, where flow approaches 60 Sv. These gyres are possibly overestimated in this study, in comparison with Semtner and Chervin’s (1992) record of around 30 Sv, because of the lack of sea ice in the model and winter wind bias. The 29.4 ± 14.7 Sv Antarctic coastal
. 2b . The surface anomalies increase in the summertime and are minimal in the winter months. The temperature variance increases in the summer months at the surface, but is constant below 100 m from the surface (not shown). The salinity variability is particularly large during the summer months ( Fig. 2b ), as sea ice melts and creates pockets of freshwater. The observed rms values shown in Fig. 2 represent the temporal variability of the temperature and salinity within a 1° × 1° square rather
. 2b . The surface anomalies increase in the summertime and are minimal in the winter months. The temperature variance increases in the summer months at the surface, but is constant below 100 m from the surface (not shown). The salinity variability is particularly large during the summer months ( Fig. 2b ), as sea ice melts and creates pockets of freshwater. The observed rms values shown in Fig. 2 represent the temporal variability of the temperature and salinity within a 1° × 1° square rather
