Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS) has brought together a comprehensive community of researchers from 9 UK institutes supported by 5 project partners including the Met Office who are experts in the atmosphere, the oceans and the land surface. The programme’s research objectives will be fulfilled through 5 research themes, outlined below.
1. Defining hiatus and surge (H/S) events and developing a conceptual framework that characterises such events
There is currently no established framework for quantifying H/S events and their main causes. SMURPHS is aiming to understand the morphology of past events and develop new ways of comparing observations and models to understand interactions between different components of the climate system (atmosphere, land and ocean), forced response and internal variability.
A multi-disciplinary team comprising researchers from Leeds (led by Piers Forster) and Reading (led by Jonathan Gregory) will test different choices of how H/S events are identified and define a precise framework within which anomalous trend periods across atmosphere and ocean responses will be interpreted.
2. Characterisation and Morphology of Hiatus and Surge (H/S) events
The aim of this theme is to determine multivariate spatial fingerprints of H/S events in observations and models, focusing on the processes that relate to the flow of energy through the climate system. A research team with members from UEA (led by Timothy Osborn), Southampton (led by Sybren Drijfhout), Reading (led by Richard Allan), National Oceanography Centre (led by Bablu Sinha) and Edinburgh (led by Gabriele Hegerl) are working to, improve global surface temperature analysis; study multivariate fingerprints of recent H/S events; and considering insights from the long instrumental record and high-resolution palaeoclimate data.
3. Unforced variability and Mechanisms of Ocean Heat Uptake
In this theme the mechanisms responsible for triggering, amplifying and extending H/S events are being examined. It aims to identify ocean dynamical mechanisms that alter ocean heat uptake (from the upper ocean, regarded as part of the surface climate system on interannual timescales, into the ocean beneath); to identify possible cloud feedback changes that alter the Earth’s energy imbalance during H/S events; and to understand how these possible drivers interact and may be linked.
The research team comprises scientists from the Universities of Southampton (led by Sybren Drijfhout) and Reading (led by Richard Allan), the National Oceanography Centre (led by Bablu Sinha) and the British Antarctic Survey (led by Andrew Meijers), with support from the UK Met Office, Laboratoire de Glaciologie et Geophysique de l’Environnement (LGGE) and the Max Planck Institute for Meteorology (MPIM).
4. Forced Response
This research theme is working to understand and bound the uncertainty in the forced-response for the 4 H/S periods. Particularly it is addressing the research aims: to understand the role of changing patterns of anthropogenic, tropospheric aerosol emissions in driving and influencing the evolution of H/S events; to determine the influence of volcanic aerosol on H/S events for both large and small eruptions, and both quiet and active periods; to identify ocean dynamical mechanisms that alter ocean heat uptake; to identify possible cloud feedback changes that alter the Earth’s energy imbalance during H/S events and to understand how these possible drivers interact and may be linked. A team of scientists from Reading (led by Keith Shine), Leeds (led by Piers Forster, Ken Carslaw, Graham Mann and Anja Schmidt), Oxford (led by Lesley Gray), UEA (led by Manoj Joshi), Southampton (led by Sybren Drijfhout) and Edinburgh (Massimo Bollasina), with support from the UK Met Office and CICERO.
5. Predictability of Hiatus and Surge Events
For natural fluctuations, in which ocean dynamics and heat transport are dominant processes, predictability lies within the initial state of the ocean. Predictability may also come from changes in boundary conditions, due to forcing associated with e.g. tropospheric aerosols or volcanic eruptions. H/S events may, in principle, derive predictability from initial conditions or boundary conditions or a combination of the two. This theme is addressing the predictability of H/S events but also examining results from real-world prediction systems.
A team from Reading (led by Ed Hawkins and Rowan Sutton), Exeter (led by Matthew Collins), Southampton (led by Sybren Drijfhout), Leeds (Anja Schmidt) and the Met Office is working to produce and exploit an ensemble of historical and future transient simulations, to establish baseline predictability and to carry out a set of model predictability experiments.
6.Interpreting the historical record
Taking uncertainty into account, this research theme led by a team from Edinburgh and Reading is seeking to reconcile understanding of the historical record with the various conclusions drawn in the literature on H/S events. It is working to separate and quantify forced and unforced contributions to H/S events and to examine the contribution of individual forcings including volcanic, solar and aerosol. The research aims to improve the estimate, with realistic uncertainty, of the contribution by greenhouse gases, unforced variability and other drivers to surface temperature and ocean warming. The research team comprises scientists from the Universities of Edinburgh (led by Gabriele Hegerl), Reading (led by Jonathan Gregory), UEA (led by Timothy Osborn), Southampton (led by Sybren Drijfhout), Leeds (led by Piers Forster), Oxford (led by Lesley Gray), and the Max Planck Institute for Meteorology (MPIM).