10 Absolute Dynamic Topography from Altimetry
177
10.6 Conclusion
While altimetric measurements have been exploited for a long time to study the
ocean mesoscale dynamics, the launch of dedicated space gravity missions as
GRACE, as well as the development of merging techniques allowing to estimate
with increasing accuracy and resolution the ocean Mean Dynamic Topography, has
led in the recent years to the better exploitation of the absolute dynamic topography
signal. This is of crucial importance for the better understanding and monitoring of
the ocean circulation. The availability in the near future of the new GOCE geoid,
whose accuracy at 100 km resolution is expected to be close to 1–2 cm, will definitively make the altimetric sciences enter a new era. However, new technology as
wide swath altimetry are emerging, pushing back the limits. Similarly, we assist to
an increasing need for coastal products (requiring higher spatial and temporal resolution). As a consequence, the optimal use of GOCE data for altimetry will require a
sustained effort of combination with other kind of data (gravimetric/oceanographic),
in order to keep on improving the estimation of the ocean absolute dynamic
topography, for the better understanding, modelling, and forecasting of the ocean
currents.
References
Andersen O (2008) The DNSC08 Global Mean Sea Surface and Bathymetry. Presented EGU-2008,
Vienna, Austria, April, 2008
Bingham RJ, Haines K, Hughes CW (2008) Calculating the ocean’s mean dynamic topography from a mean sea surface and a geoid. J Atmos Ocean Tech 25(10):1808–1822,
doi:10.1175/2008JTECHO568.1
Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the
Tropical Pacific Ocean. J Phys Oceanogr 32:2938–2954
Cheney RE, Marsh JG, Beckley BD (1983) Global mesoscale variability from collinear tracks of
Seasat altimeter data. J Geophys Res 88(C7):4343
Ducet N, Le Traon PY, Reverdin G (2000) Global high resolution mapping of ocean circulation
from Topex/Poseidon and ERS-1 and -2. J Geophys Res 105(C8):19477–19498
Fu LL (2006) Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter
observations. Geophys Res Lett 33:L14610, doi:10.1029/2006GL026245
Fu LL, Cazenave A (2001) Satellite Altimetry and Earth Sciences: A Handbook of
Techniques and Applications. International Geophysics Series, Vol. 69, Academic Press,
San Diego
Haines K, Johannessen J, Knudsen P, Rio MH (2010) An ocean modelling and assimilation guide
to using GOCE geoid products (in preparation)
Hernandez F, Schaeffer P (2001) Surface Moyenne Oceanique: support Scientifique à la mission
altimetrique Jason-1, et à une mission micro-satellite altimétrique. Contrat SSALTO 2945 –
Lot2 – A.1. Rapport final n ◦ CLS/DOS/NT/00.341, CLS, Ramonville St Agne
Hughes CW (2005) Nonlinear vorticity balance of the Antarctic Circumpolar Current. J Geophys
Res 110:C11008, doi:10.1029/2004JC002753
Hughes CW, Bingham RJ (2006) An oceanographer’s guide to GOCE and the geoid. Ocean Sci
Discuss 3:1543–1568
177
10.6 Conclusion
While altimetric measurements have been exploited for a long time to study the
ocean mesoscale dynamics, the launch of dedicated space gravity missions as
GRACE, as well as the development of merging techniques allowing to estimate
with increasing accuracy and resolution the ocean Mean Dynamic Topography, has
led in the recent years to the better exploitation of the absolute dynamic topography
signal. This is of crucial importance for the better understanding and monitoring of
the ocean circulation. The availability in the near future of the new GOCE geoid,
whose accuracy at 100 km resolution is expected to be close to 1–2 cm, will definitively make the altimetric sciences enter a new era. However, new technology as
wide swath altimetry are emerging, pushing back the limits. Similarly, we assist to
an increasing need for coastal products (requiring higher spatial and temporal resolution). As a consequence, the optimal use of GOCE data for altimetry will require a
sustained effort of combination with other kind of data (gravimetric/oceanographic),
in order to keep on improving the estimation of the ocean absolute dynamic
topography, for the better understanding, modelling, and forecasting of the ocean
currents.
References
Andersen O (2008) The DNSC08 Global Mean Sea Surface and Bathymetry. Presented EGU-2008,
Vienna, Austria, April, 2008
Bingham RJ, Haines K, Hughes CW (2008) Calculating the ocean’s mean dynamic topography from a mean sea surface and a geoid. J Atmos Ocean Tech 25(10):1808–1822,
doi:10.1175/2008JTECHO568.1
Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the
Tropical Pacific Ocean. J Phys Oceanogr 32:2938–2954
Cheney RE, Marsh JG, Beckley BD (1983) Global mesoscale variability from collinear tracks of
Seasat altimeter data. J Geophys Res 88(C7):4343
Ducet N, Le Traon PY, Reverdin G (2000) Global high resolution mapping of ocean circulation
from Topex/Poseidon and ERS-1 and -2. J Geophys Res 105(C8):19477–19498
Fu LL (2006) Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter
observations. Geophys Res Lett 33:L14610, doi:10.1029/2006GL026245
Fu LL, Cazenave A (2001) Satellite Altimetry and Earth Sciences: A Handbook of
Techniques and Applications. International Geophysics Series, Vol. 69, Academic Press,
San Diego
Haines K, Johannessen J, Knudsen P, Rio MH (2010) An ocean modelling and assimilation guide
to using GOCE geoid products (in preparation)
Hernandez F, Schaeffer P (2001) Surface Moyenne Oceanique: support Scientifique à la mission
altimetrique Jason-1, et à une mission micro-satellite altimétrique. Contrat SSALTO 2945 –
Lot2 – A.1. Rapport final n ◦ CLS/DOS/NT/00.341, CLS, Ramonville St Agne
Hughes CW (2005) Nonlinear vorticity balance of the Antarctic Circumpolar Current. J Geophys
Res 110:C11008, doi:10.1029/2004JC002753
Hughes CW, Bingham RJ (2006) An oceanographer’s guide to GOCE and the geoid. Ocean Sci
Discuss 3:1543–1568