Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Basil R. Stanton x
  • Refine by Access: All Content x
Clear All Modify Search
Basil R. Stanton

Abstract

Variations in coastal sea level in the weather band (periods 5–20 days) on the west coat of New Zealand can largely be explained in terms of wind-forced coastal-trapped waves. Long-wave theory was applied to the North Island shelf with some success in hindcasting sea level at New Plymouth. On the southern South Island shelf, the sea level signal was found to propagate like a mode-one coastal-trapped wave, but the complex topographic variations made application of simple long-wave theory impossible. The sea level signal in the south of the region was highly correlated with alongshore wind stress over the shelf region to the north, suggesting that alongshore wind stress is the major forcing mechanism. In contrast, the generation of coastal-trapped waves by a coastal flux through Taranaki Bight/Cook Strait appears to be the dominant mechanism over the northern and central South Island shelf, from the present and previous studies.

Full access
Basil R. Stanton

Abstract

Wind data for the period July–October 1994 from an ocean buoy moored off the west coast of New Zealand have been compared with model wind data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and data from the nearest land-based station. The buoy and ECMWF winds were highly coherent and strongly polarized in the alongshore direction, suggesting that the ECMWF model correctly accounts for the orographic effect of the mountainous New Zealand landmass on the prevailing synoptic weather systems. At low frequencies, the ECMWF data can be used as a substitute for in situ wind data in oceanographic applications in the New Zealand region. This is a similar result to that reported in some Northern Hemisphere studies. In contrast, winds at the land-based site were much weaker and less strongly aligned alongshore than winds recorded offshore.

Full access
Madeleine L. Cahill, Jason H. Middleton, and Basil R. Stanton

Abstract

The coastal ocean response to wind forcing on the west coast continental shelf of South Island, New Zealand is examined using current, sea level and wind observations. Weather band motions over the northern region of the shelf appear to be dominated by the response to wind-forced flux through Cook Strait. Through-strait forcing is still evident in the currents of the southern region but west coast alongshore wind-forcing is also important.

Most of the variance of nearshore weather band currents in the northern region of the shelf can be described in terms of coastal-trapped waves (CTWs). A fit of CTW modes 1 and 2 to the observations in that region indicates the equal importance of both modes, in agreement with the theories of strait-generated CTWS. Farther south, the across-shelf depth profile alters dramatically such that CTW structures change from being almost barotropic in the northern region to highly baroclinic. This rapid change in topography suggests that considerable scattering of CTWs might occur, a hypothesis which is supported by current observations in the southern region of the shelf.

Full access