New Zealand Journal of Marine and Freshwater Research abstracts

---

In which direction is the mean flow through Cook Strait, New Zealand - evidence of 1 to 4 week variability?

R. A. HEATH

New Zealand Oceanographic Institute Division of Marine and Freshwater Science Department of Scientific and Industrial Research P. O. Box 12-346, Wellington North New Zealand

Abstract Current-meter observations at three sites in the narrows of Cook Strait over individual periods of 30-82 days confirm the dominance of the semi-diurnal tidal flow. The major semi-diurnal constituent, the M₂ tide, has near degenerate ellipses aligned through the Strait with amplitudes decreasing towards the west. Daily mean currents are dominated by flows with 2 and 4 weekly periods which are correlated with the wind (mainly the through Strait component) and possibly associated with the fortnightly MSf (4-9 cm s~') and monthly Mm (4-7 cms~') tides (mainly the across Strait component). Mean currents over the observational periods were directed through the Strait, with a southward component at about 4cms"¹ on the western side and a 5-14cms¹ northwards component on the eastern side. An appreciable (1-12 cm s¹) 6.2 hour M₄ tide is also present with flow directed mainly across Cook Strait. The Mm, MSf, and M₄ compound tides are probably associated with a response to interaction of the non-linear field acceleration of the semi-diurnal tide producing flow across the sloping sea floor.

Keywords tidal currents; Cook Strait; compound tides; semi-diurnal tide

New Zealand Journal of Marine and Freshwater Research, 1986, Vol. 20: 119-137 Received 22 May 1984; accepted 7 May 1985

PDF file of entire paper: medium quality (907K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page