Wind‐driven upwelling and surface chlorophyll blooms in Greater Cook Strait

Abstract

We present the results of a combined observational and numerical study to investigate cool plumes of nutrient‐rich upwelled water that emanate near the Kahurangi Shoals and extend into Greater Cook Strait. Surface temperature and chlorophyll are mapped using satellite observations to produce surface climatologies, to validate a numerical simulation and to show the utility of using spatial temperature differences as a measure of upwelling. We find upwelling near the Kahurangi Shoals is strongly wind‐driven in the weather band. Upwelling occurs at all times of the year, but its surface signature is only visible in summer months. The upwelled nutrient‐rich water supports increased primary production compared to surrounding waters, particularly in summer when the water column is more stratified and surrounding surface waters are presumably nutrient depleted.

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