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Paul Ritchie

Postgraduate

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Telephone: 01392 723590

Extension: (Streatham) 3590

I'm currently a postdoc studying potential tipping points in UK ecosystems from future land-use and climate change projections supervised by Prof. Tim Lenton and Dr. Anna Harper. A system is often described to pass a tipping point when gradual changes made to input levels or rates cause the output to suddenly change state. My current project involves working with the Joint UK Land Environment Simulator (JULES) a land-surface model to look for tipping events in carbon stocks, greenhouse gas emissions and frehwater fluxes.

During my PhD (also here at Exeter) I studied the underlying dynamics behind tipping points, supervised by Dr. Jan Sieber and Prof. Peter Cox. In particular my work studied a more recent concept of tipping known as rate-induced tipping. For classical tipping events such as a slow passage through a fold bifurcation, so-called early-warning indicators (increase in autocorrelation and variance) have been developed to detect the approach of a tipping point. However, for rate-induced tipping the dynamics are different and thus it is unclear if these early-warning indicators can still be used for rate-induced tipping events. However, we were able to show that there exists both a delay in the time of tipping from when one would expect to see tipping and in the early-warning indicators. Furthermore, these delays are consistent such that we conclude that early-warning indicators can be used for rate-induced tipping events, see papers below.

 

Papers:

Probability of noise- and rate-induced tipping, 2017

Early-warning indicators for rate-induced tipping, 2016

 

Presentations:

Dynamics Days Europe, Szeged, Hungary, June 2017

SIAM Conference on Applications of Dynamical Systems, Snowbird , USA, May 2017

Tipping Points Reading Group, August 2016

Climate Tipping Points Workshop, Dartington Hall, April 2016

Dynamical Systems Reading Group, November 2015

Dynamics Days Conference, Exeter, September 2015, Poster

Equadiff Conference, Lyon, France, July 2015

SIAM Conference on Applications of Dynamical Systems, Snowbird, USA, May 2015

Dynamical Systems Reading Group, 2014

Edinburgh Tipping Points Worshop 2013, Poster

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