Climate Freund

My research integrates diverse evidence from various time scales, combining observations, paleoclimate data, and climate model simulations to unravel the complexities of the climate system.

Climate variability and changes
I am a Lecturer in Climate science who specialises in climate variability of the tropics and extra-tropics across seasonal to decadal time scales. My research interests include: the El Niño Southern Oscillation and its related teleconnections, regimes influencing droughts and precipitation anomalies, advanced statistical and machine learning methods and their dynamical links, implications and applications.

Integrating Evidence Across Time Scales
My passion is to combine multiple lines of evidence (past proxy archives, observational data and future model simulation data) to gain new insights into current and future changes in climate. A strong seasonal focus of my work provides unprecedented opportunity to study climate-scale climate processes by contextualizing key climatic hazards such as droughts, rainfall extremes and recent trends and their dynamical links. Climate processes are evaluated by using a combination of observational data, seasonal forecasts such as ACCESS-S2, CMIP models, and statistical techniques to understand the current state of the climate, predict future changes, and assess the reliability of forecasts.

news

Sep 27, 2024	The Conversation article: Australia may be facing another La Niña summer. We’ve found a way to predict them earlier, to help us prepare.
Sep 23, 2024	New paper on ENSO diversity, transitions, and projected changes

latest posts

Oct 29, 2024	ENSO transitions - a game of domino
Sep 23, 2024	La Niña possible, but not very likely
May 06, 2019	Unraveling the history of El Niño flavours

selected publications

Interannual ENSO diversity, transitions, and projected changes in observations and climate models

Mandy B Freund, Josephine R Brown, Andrew G Marshall, Carly R Tozer, Benjamin J Henley, James S Risbey, Nandini Ramesh, Ruby Lieber, and S Sharmila

Environmental Research Letters, Sep 2024

Abs HTML PDF Video

Diverse characteristics of El Niño Southern Oscillation (ENSO) events challenge the traditional view of tropical coupled ocean-atmosphere systems. The probability of a transition from one type of event to another is influenced by multiple factors of which many are projected to change. Here we assess the likelihood of ENSO transitions in observations and climate models, including a distinction between events that peak in the Eastern Pacific (EP) and Central Pacific (CP). We find that the initial ENSO state influences the likelihood of certain transitions and that some transitions are not physically possible or stochastically likely. For example, transitions to CP events are more likely than EP events except from a neutral state. We also find that El Niños tend to occur as singular events compared to La Niñas. While consecutive El Niño and La Niña events of EP type are possible, opposing EP events do not occur in succession. We identify several transitions likely driven by internal dynamical processes including neutral conditions to El Niño, CP El Niño to another El Niño, EP El Niño to CP La Niña, CP La Niña to CP El Niño and La Niña, and EP La Niña to neutral and CP El Niño. Projections of future transitions show an increased probability of transitions to CP El Niño events while transitions to EP La Niña events become less frequent under a high-emissions scenario. Accordingly, transitions to these events become more and less likely, respectively. We also find changes in the likelihood of specific transitions in a warming world: consecutive CP El Niño events become more likely while EP El Niño events become less likely to transition into CP La Niña events. These changes are expected to occur as early as 2050 with some changes to be accelerated by the end of the 21st century.