Is the Oceanography of the New Zealand Subantarctic Region Responding to the Tropics?

The Campbell Plateau, south of New Zealand plays an important role in New Zealand’s regional climate and its oceanography may have a significant impact on fluctuations in fish stocks and marine mammal populations. It is located between the Subtropical and Subantarctic Fronts and exhibits marked variability over long time scales. It has been previously assumed, because of its location, that the Campbell Plateau oceanography is driven by Subantarctic and polar processes. Recent analysis, presented here, suggests this in not the case, and instead forcing comes from the tropics and subtropics. This is supported by positive correlations of Sea Level Anomalies (SLA) and Sea Surface Temperature (SST) with the Southern Oscillation Index (SOI) with SOI leading changes on the Campbell Plateau by two months for SLA and seven months for SST. Here we will present evidence of the similarity between the Campbell Plateau and the Tasman Sea SLA trends which suggests a closer relationship with the subtropical region. Satellite collected SLA data and SST from the last two decades are investigated to understand trends and long-term variability over the Campbell Plateau and its relationship with the surrounding open ocean, and other potential remote drivers of variability.