Variability Report, December 2017

The Variability team took part in two key ENSO workshops in Busan, South Korea, and at the University of New South Wales. You can find reports on both of them in this newsletter. The Busan workshop was of particular note because it suggests a new way of holding workshops that leads to distinct research outcomes.

Dietmar Dommenget visited Germany in September to foster collaborations with the Max Planck Institute and ETH Zurich on model development and the tuning of climate models. Dietmar also continues to build collaborations in Germany and Australia to enable the Monash Simple Climate Model to be used as an education tool in high schools and museums.

The program also produced a number of insightful papers.


Fig 1: From Paul Spence paper showing how distant winds enhance melting on West Antarctic ice sheet.

Paul Spence produced a remarkable paper, which showed how strong winds along the East Antarctica coastline generated ocean Kelvin waves. When these Kelvin waves encountered the steep topography of the West Antarctic Peninsula pushed warmer water under the ice shelves leading to much more rapid melting in this area.

An evaluation of CMIP model dynamics (pdf) by Vilayeta and Dommenget found that nearly all feedbacks in models were underestimated, even though they appeared to simulate the overall statistics of ENSO variability. It was found the model errors compensated for each other, resulting in good simulations but for the wrong reasons.

Another examination of models and how they represented ENSO events by Luo et al, which was prompted by the unusual nature and increasing complexity of recent events, found a substantial mismatch between model simulations and observed trends in the tropical Pacific. The paper revealed that common model biases were forcing models into El Nïno like warming trends that are inconsistent with observed La Nina trends.

The Variability team has also been looking at rainfall in the Australian monsoonal regions, which generally occurs in short bursts. The question has been whether these short bursts are initiated by tropical or mid-latitude weather systems. A study by Narsey et al. found that mid-latitude systems were responsible for two out of three monsoonal bursts, with tropical waves and others systems contributing to the rest. 

  • Photo (top left): Crashing wave by Sasha Lebdeva (Unsplash).
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