Comparison of current meter and altimeter data in the Southern Indian Ocean

Elaine McDonagh		School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, U.K. e.mcdonagh@uea.ac.uk http://www.uea.ac.uk/env
Karen Heywood		School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, U.K. k.heywood@uea.ac.uk http://www.uea.ac.uk/~e280/karen.htm

Abstract

In this study data from a current meter mooring was compared with data from a satellite altimeter. This analysis was prompted by the positioning of a current meter mooring within 12 km of an altimeter crossover point. The mooring of interest here and nine others were positioned in the Crozet-Kerguelen gap, South Indian Ocean, between March 1993 and March 1994 as part of a two-cruise campaign named the Antarctic Deep Outflow Experiment (ADOX). It is necessary for the mooring to lie on a crossover point rather than just a single ground track so that orthogonal components of the velocity can be resolved rather than just that component perpendicular to the ground track. Velocities from the current meters were extrapolated to the surface to compare with the altimeter measurements. Using this favourable comparison the variability of the velocity, and therefore the transport in this region where vertical coherence is high, can be inferred for other years of the altimeter mission. An attempt is also made to deduce the mean flow in other years of the altimeter missi