Wairarapa Coastal Current influence on sea surface temperature in Hawke Bay, New Zealand

Abstract

The Wairarapa Coastal Current (WCC) flows along the east coast of the North Island, New Zealand. This current has been relatively little studied, and there are few direct measurements of its mean and variability. Here, an indirect method is used to gain some insight into the WCC variability and its effect on coastal temperature. Eight years of coastal temperature from Napier in Hawke Bay are modelled as a bivariate linear expansion of alongshore windstress and solar radiation. In the frequency domain, the modelled temperatures are coherent with observed temperatures, and in the time domain, they are positively correlated for 80% of the time. The model results suggest both that variations in the WCC are wind-driven, and that alongshore advection accounts for most of the temperature change at Napier. Periods when the modelled temperature is not correlated with observed temperature could be because of episodes of enhanced upwelling, or large-scale influences breaking down the alongshore temperature gradient. © 2002, Copyright Taylor & Francis Group, LLC.