Professor Grant Bigg

Department of Geography

Professor in Earth Systems Science

Grant.Bigg@Sheffield.ac.uk
+44 114 222 7905

Full contact details

Professor Grant Bigg
Department of Geography
C7
Geography and Planning Building
Winter Street
Sheffield
S3 7ND
Profile

Grant Bigg obtained his BSc in physics and applied mathematics from the University of Adelaide, Adelaide, South Australia in 1978, with a BSc (Honours) in applied mathematics the following year. He then became a Tutor in the Department of Applied Mathematics, University of Adelaide, working part-time on a PhD on Diffraction and trapping of waves by cavities and slender bodies. This was completed in 1982, the same year he had a pre-doctoral fellowship at the 1982 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution.

In 1983 he moved overseas to the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge for a postdoctoral position in The sensitivity of inverse methods in oceanography. A year later, he followed his Principal Investigator, Adrian Gill, to the Hooke Institute in the Department of Atmospheric, Oceanic and Planetary Physics, University of Oxford, where his postdoctoral work broadened to marine climate change.

In 1987 he became a lecturer in the School of Environmental Sciences, University of East Anglia, and was promoted to Senior Lecturer in 1996. He moved to a Chair in Earth Systems Science at Sheffield in 2003, and served as Head of Department from 2006-2012. He currently lectures on oceanography and polar environments.

Grant is a Fellow of the Royal Meteorological Society and the Royal Geographical Society; he is a member of the Quaternary Research Association, the American Meteorological Society and the American Geophysical Union. He was a member of the Council of the Royal Meteorological Society in the early 1990s and editor of the Society's journal, Weather, for five years until 2003. He has been an Associate Editor of the Journal of Climate and of the International Journal of Oceanography and is currently Chair of the Editorial Board of the Challenger Society for Marine Science’s Ocean Challenge.

He has acted as external examiner for postgraduate degrees in Britain, the Netherlands, Australia and Jamaica and undergraduate and postgraduate degrees in Britain.

Grant is a keen walker, with his border terrier. He has also recorded meteorological data on two continents for almost 40 years.

Research interests

Research Interests

Ocean and climate modelling, marine climate change specialising in polar and tropical regions, with special interest in synoptic or meso-scale weather systems. Palaeoceanography: modelling and interpreting observations. Icebergs, and their role in the ocean's freshwater flux, both today and in the Quaternary. The interactions between climate change and society.

Current research

The common theme to all my research until recently has been marine climate change. However, many threads contribute to this theme. A major thread is the use, and development, of ocean circulation models to understand climate change on scales from global and millennial to local and sub-monthly. I use a combination of models and remote sensing, with interpreting oceanographic and lower atmospheric data, to increase our understanding of the climatic interaction between the atmosphere and ocean. I use iceberg trajectories to study glacial freshwater inputs to modern and Quaternary oceans. My primary focii of recent years can be divided into the global thermohaline circulation, icebergs and tropical climate change. More recently, however, there has begun to be an increased emphasis on the role environmental change plays in society.

Global thermohaline circulation

The possibility of future shut-down of convection in the North Atlantic Ocean, and a consequent reduction in the strength of the Gulf Stream, with associated cooling of western Europe has been much in the news in recent years. While the prospects for this occurring remain limited it is clear that the ocean circulation has changed significantly, and rapidly, at times in the past. I use models to explore the regimes under which change can occur, and the consequences of such change.

Highlights of this work include

  • Discovery of the impact of opening of the sea connection between the Arctic and Atlantic through the Canadian Seaways. Without the freshening influence of Arctic waters on the Labrador Sea the latter becomes much saltier, and more subject to convection, allowing more northward heat transport. An open connection through the Canadian Archipelago therefore acts as a negative feedback on the North Atlantic overturning circulation.
  • Discovery that the location of past injection of massive freshwater or iceberg fluxes to the glacial ocean leads to significantly different climate impact. From this work, it has become clear that a massive iceberg release about 30,000 years ago, known as H3, probably occurred in the European Arctic, rather than from North America, as previously believed.
  • Discovery that variation in sea level over the Quaternary has led to dramatic changes in the thermohaline circulation, due to enhancement of tidal mixing during low sea level stands.

This work has been carried out with Martin Wadley, Richard Levine of the Meteorological Office, and Mattias and Clare Green from Ocean Sciences at Bangor University, Wales, and funded by NERC and the Leverhulme Trust.

Icebergs

Iceberg debris has been used as a tracer for past ocean circulations in the Quaternary since the mid-1970s. However, until the mid-1990s there was little attempt to integrate this information into climate models. I developed a dynamic and thermodynamic model of iceberg movement that can be used in a coupled mode within a larger-scale climate model, or run in a non-feedback mode, to give a dynamical view of how ice-rafted debris distributions came about. This model has been tested in both hemispheres of the modern ocean and used in glacial mode.

Highlights of the work include

  • Discovery that iceberg meltwater may contribute as much as the precipitation budget to freshwater inputs to significant regions of the Southern Ocean. As convection around Antarctica is critically dependent on the salinity of waters following sea-ice formation the iceberg signal acts as a negative feedback on deep water formation.
  • Use of the model to assist interpretation of glacial iceberg-rafted debris signals. Using various palaeoceanographic indicators ranging from carbon isotopes to magnetic strengths of iron fragments in ocean core sediments the iceberg model has been used with various ocean model circulations to narrow down the characteristics of the glacial ocean circulation state. The most compatible ocean state is one with most deep water formation in the Southern Ocean.
  • Discovery of the relationship between large scale iceberg releases Modelling the twentieth century iceberg flux from Greenland, which, from its agreement with observed and marine core data from either side of Greenland, suggests that the dominant calving location of icebergs has shifted north during the century.

Remote sensing has also been used to help validate the iceberg trajectory model, and to move towards an iceberg calving flux for Antarctica, and a sea-ice hazard tool for the Arctic. This work has been carried out in collaboration with Keith Nicholls of the British Antarctic Survey, Barbara Maher of Lancaster University, Rupert Gladstone, Sarah Watkins, Tiago Silva, Richard Levine, Jen King, Clare and Mattias Green from Bangor University, Wales. The work has been funded by NERC and Kongsberg Satellite Services.

Tropical climate change

El Niño dominates work on the tropical climate but is only one aspect. I have been studying interannual variability in the the tropical Atlantic, both links to the Pacific variability of El Niño but also modes of variability that are self-contained within the Atlantic. The latter form an important component of Atlantic climate change. Both observational and modelling work on establishing the mechanisms underlying such change are ongoing.This work has been carried out with Alex Georgiadis, Masamichi Inoue of Lousiana State University, Itsuki Handoh, and Adrian Matthews and Dave Stevens of the University of East Anglia, and funded by NERC, NATO, the Royal Society and the University of Sheffield.

Publications

Books

  • Bigg GR (2015) Icebergs: Their Science and Links to Global Change. Cambridge: Cambridge University Press. RIS download Bibtex download
  • Bigg GR (2003) The Oceans and Climate. Cambridge University Press. RIS download Bibtex download
  • Bigg GR (2003) The Oceans and Climate, Second Edition. Cambridge University Press. RIS download Bibtex download

Journal articles

Chapters

Conference proceedings papers

Teaching interests

While my specialist teaching is in the fields of oceanography and meteorology, throughout what I teach at both undergraduate and postgraduate level I try to convey the importance of thinking of subjects from an interdisciplinary perspective, using a range of tools students pick up in our skills modules.

This is very much a research-led teaching style, exposing students to current ideas about my specialist subjects as well as the other areas I teach, or the wide range of dissertation topics I supervise. While this involves large-scale lectures when necessary, it also involves tutorial groups and individual supervision, particularly at Masters level.