Inter-comparison between Aanderaa and Potok current meters deployed during INDEX programme

Abstract

The results of inter-comparison study between the Aanderaa RCM 7 and Potok 2M current meters deployed in the Southern Equatorial Indian Ocean during April to September 1996 in phase-2 of the INDEX programme has been presented. The vector averages of currents for seven consecutive 10-day ensembles of both Aanderaa and Potok current meters revealed the presence of a meridional flow, with both the Aanderaa and Potok current meters generally showing the identical ensemble averaged northerly/ southerly directions. The cross spectral analyses showed that both the current meters were coherent for frequencies less than 0.2 cph at 0.01 significance level for both the u and v components of currents. The phase difference between the two types of current meters was nearly zero degree in the above said frequency range indicating that both registered the same signal. At the inertial frequency, rotary spectral analysis showed that the currents are anticlockwise (southern hemisphere) and cross spectral analysis showed that the v component lags behind the u component by 90 degrees.