Climate variability of the Great Barrier Reef in relation to the tropical Pacific and El Niño-Southern Oscillation

Abstract

Understanding the nature and causes of recent climate variability on the Great Barrier Reef (GBR), Australia, is fundamental to assessing the impacts of future climate change on this complex ecosystem. New analytical tools, improved data quality and resolution, longer time-series and new variables provide an opportunity to re-assess existing paradigms. Here, we examined sea surface temperature (SST), sea level pressure, surface winds, sea surface height and ocean currents for the period from 1948 to 2009. We focussed on the relationship between GBR surface climate and the wider tropical Pacific, and the influence of El Niño-Southern Oscillation (ENSO) events. Also, for the first time, we investigated the impact of the El Niño/La Niña Modoki phenomenon. Although neither type of ENSO event is a primary driver of inter-annual climate variability on the GBR, their influence is conspicuous. Classical ENSO events have a strong signature in the atmospheric circulation in the northern GBR but no significant relationship with SSTs and the opposite applies for the southern GBR. Conversely, El Niño/La Niña Modoki is significantly related to summer SSTs on the northern GBR, but not for the southern GBR. This study enhances our understanding of tropical Pacific and GBR climate drivers and will improve future predictions of change in climate variables that are likely to impact on the complex GBR ecosystem.