March 29, 2019 | Published by |

After some well deserved (and in many cases long overdue) summer holidays the Centre has seen a rapid ramp up of research in the last couple of months. Cross research program collaboration has intensified, focused on improving our modelling systems, using our models to examine key phenomenon and in particularly how we can improve the representation of extreme events.

There have been multiple workshops bringing researchers together within the Centre, and with strong engagement from affiliated researchers. We have accelerated our research focused on the Southern Annular Mode for example, dealing with significant questions and setting in place a range of research opportunities over the coming years. We played a significant role in a national drought workshop and are now identifying the key priorities in taking specific recommendations forward. A dynamic environment now exists with regular video conferences among researchers, students and associates in most of our research programs.

We are now 18 months into the life of the Centre, and so it is not surprising that Centre work is emerging in the international literature.

In the rainfall program three papers with quite a technical focus have examined data assimilation and the dynamics behind precipitation.  These papers will underpin future research of the Centre but also have global impact. The data assimilation work involved Kalman filtering and assimilation of satellite data to improve forecasting. The dynamics research highlighted the need to improve relatively short lived features responsible for convergence lines in order to improve climate model simulations in the tropics.

Beyond this foundational model research, the program also produced an observational study that examined hybrid cyclones, including the one that damaged electrical infrastructure in South Australia in 2016, to understand how, when and where these destructive storms form. While the processes that created them were similar to tropical cyclones, they occurred at the other end of the year – from May to September – and generally formed in the Great Australian Bight or Tasman Sea.

A fascinating piece of cross-program research from the rainfall and drought programs looked at whether soil moisture influenced precipitation in Australia. It found a link, but by no means a simple link as the influence was in completely opposite directions between the north and south of Australia. In Northern Australia a wetter soil produced more rainfall but to the south, particularly the south east, drier soils led to increased precipitation. As climate models increase in resolution, this will be an important consideration determining how rainfall may change in the future. 

The heatwaves and cold air outbreaks program has continued its world leading research into marine heatwaves. Researchers have put forward a new method for categorising and naming marine heatwaves that is similar to what is currently used for tropical cyclones. The importance of taking this approach to heatwaves was highlighted in another paper by the program that looked at how marine heatwaves were creating step-changes that completely reconstructed marine ecosystems around Australia and the world.

Over land, the heatwaves team explored how ENSO impacted heatwaves across Australia, revealing the soil moisture and surface energy balance of the land surface in north and northeastern Australia modified ENSO impacts. This interaction may help improve forecasts for this region. In another study, the heatwaves team explored the impacts of some Australian cities on overnight temperatures during heatwave events. They found in most cases – with the exception of Perth – temperatures were 1.2°C – 3.3°C warmer than neighbouring rural areas.

The Drought team has produced a much-improved dataset for global river flows and another for land degradation. It also produced a paper that will give agricultural and ecosystem researchers a better understanding of future vegetation changes with global warming. Perhaps the highlight of the past three months was the development of an important theoretical formula that replaces the Priestley-Taylor equation. The new formula provides a fundamental new insight into to how radiation, evaporation and temperature are interlinked. This opens the way to use these results to investigate how temperature might evolve into the future.

In our Climate Variability and Teleconnections program, researchers are revealing new ways that heat is transferred across the ocean, from the tropics to the sub Antarctic at a time when summer sea-ice around the Antarctic is at an all-time low for the instrumental record. Members of the team have also been part of a paper that has called for improvements in the Tropical Observing System, which is crucial in monitoring and forecasting the development of El Niño and La Niña events. Coincidentally, around the same time other researchers in the program published a paper in Nature that highlighted the importance of the Observing System. It showed an increase in the strength and impact of future El Niños appeared consistently across multiple climate models.

The vibrancy of our research has also been matched over the past four months with the accolades received by our researchers. Since our last newsletter in December, AMOS again acknowledged the contribution of CLEX researchers by making Deputy Director Todd Lane an AMOS Fellow, awarding Christian Jakob the 2018 Morton Medal; and announcing Andrew King as the inaugural winner of the AMOS Award for Science Outreach. Student Dominic Thorn also received the AMOS Melbourne Chapter Regional Award for his Masters.

Other triumphs include Julie Arblaster being added to the Highly Cited List produced by Clarivate Analytics and the award of the John and Allen Gilmour Award from the Melbourne University faculty to Pavan Harika Raavi. A recent trip by Joshua Soderholm to Argentina where he studied storms and large hail events resulted in him being invited by The Royal Society of Victoria to present his work on severe weather. I was honoured to be given an Order of Australia for distinguished service to science, which, as I noted at the time, gave me my first dose of imposter syndrome.

An important annual process for the Centre is the production of our Annual Report, which is available online now, here. For all of you linked with CLEX, the Annual Report celebrates successes, but also identifies our priorities in 2019. Please take a look at our priorities listed in the report. If you see areas you want to engage with just contact the research program lead. They will be very pleased to hear from you.

Best wishes,

Prof Andy Pitman
Director Centre of Excellence for Climate Extremes