New - El Nino's, volcanoes and human colonisation in the South Pacific
Establishing well dated, quantitative, highly resolved palaeoclimate data for the major climate systems of the south Pacific has become a research priority owing to the paucity ofinstrumental data from this critical region of the Earth. Such information is vital for fully understanding inter-hemispheric climate linkages, global energy fluxes and cyclone activity; the latter essential for those vulnerable populations inhabiting the islands in this region. We will use climate proxies stored within lake sediments to reconstruct the magnitude and rate of change of past climate over millennial timescales in a region from which little is currently known regarding past environmental change.
New - The legacy of cyclone Pam: A unique opportunity to build a long term record of cyclone activity in the western tropical Pacific. (NERC Urgency Grant) This project is built on the unique opportunity provided by the recent Cyclone Pam, to quantify the biogeochemical signature of a specific and extreme (second lowest pressure recorded on earth) tropical cyclone; and to use this “fingerprint” to unequivocally identify past cyclones over longer (1-5ka) periods of time during which the key drivers of cyclogenesis in the tropical Pacific, are known to have changed. During El Niño and positive-phase Interdecadal Pacific Oscillation (IPO), countries such as Vanuatu, which under normal conditions lie within the South PacificConvergence Zone (SPCZ), experience increased tropical cyclone activity. However, the data on which these observations and models are based are short (<50-100 years). Lake sediment archives from the tropical south Pacific are rare, yet are known to contain coherent, long term records of environmental change and proxy data from which high resolution climate records can be extracted. On Efate island, Vanuatu, Lake Emaotul provides a unique opportunity to recover a long coherent lake sediment archive from within a key region of the wider Pacific climate system. It is known that on inter-annual to inter-decadal timescales pan-Pacific climate phenomena such as the ENSO and IPO cause the SPCZ to shift position. El Niño events and a positive phase SOI/IPO influence the SPCZ by shifting it northeast into a more zonalorientation. Climate modelling has suggested that with future global warming the SPCZ will more frequently adopt a zonal orientation, thus increasing the likelihood of extreme cyclone events impacting on Vanuatu. However, this understanding is based on relatively short and partial climate records from the region that do not include the extremes of ENSO observed in the lake sediment records. Thus a greater understanding of how the SPCZ and associated cyclone event frequency and magnitude have responded to global climate oscillations over multi-centennial timescales is vital for our understanding of Pacific cyclone activity in the past and in the future.
2009 - 2012 DEFRA Funded Project in collaboration with ADAS, CEH adn QMUL. Increasing teh Evidence base for the ecological impact of agriculturally derived sediments. Porf Sear leads the teams responsible for a) Development of a national scale typology of river sensitivity to fine sediment impacts; b) development of a major national facility for simulating spawning habitats; c) experiment to determine impacts of different fine sediment loads derived from different sources on incubating salmonids, Grayling and Dace; d) Deveopment in collaboration with Dr D.J.Smallman; Ann Stringfellow (CEES) of a methodology for fingerprinting organic sediments in spawning gravels; e) measurment of sediment oxygen demand of fine sedimnets in spawning gravels; f) numericalmdoelling of fine sediment routing and infiltration into spawning habitats based on the ADAS PSYCHIC sediment delivery model.
2009-11 - NERC Project on the impacts of high magnitude flood events on flood routing and physical habitats. PI in collaboration with Bristol University. The project is based around a comprehensive re-survey of the River Derwent, Cumbrian following the November 2009 flooding. A combination of repeat Fluvial Audit, topographic survey, lake coring and hydraulic modelling has ben used to construct a sediment budget for the 2005 and 2009 flood events. This has been linked to the changes in physical habitat following major morphodynamic adjustments. 2-Dimensional hydrodynamic modelling is being used to quantify the impacts of the 2009 floods on flood conveyance. The project is also investigating the role of large wood on physical habitat and morphodynamic changes, and the use of CAT-Scanning and ITRACs analysis for determinination of flood chronologies from lake Basenthwaite.
2008-10 Engish Heritage and Esmee Fairbarin Foundation; Dunwich Project. On-going project to map, visualise and understand the former medieval town of Dunwich in relation to the process of long term coastal erosion and sea level change. The project has led to major international media interest, including work or the BBC. The project has produced the first ever town sale survey fothe Dunwich site, including the identification of four former religeous buildings. Collaboration with MaCartney AS has led to the first ever use of DIDSON acoustic imaging equipment on a non-wreck archaeological site. Further information is availabel from the project website http://www.dunwich.org.uk/.
2009- Atlantic Salmon Trust - Deriving past Salmon populations from lake sediment records. This project in collaboration with the BGS, is developing methods for deriving proxy indicators of Atlatnic Salmon populations based on novel stabel isotope and ADNA preserved in lake sediments. Initial work on Loch Insh, Speycatchment, shows strong correlations between historic trends in salmon popoulations and species of diatom and marine derived nutrients.
2009 - British Society for Geomorphology 50th anniversary Project to develop a national website and mapping programe for UK geomorphology. The prject is led by Professor Janet Hooke and involves Prof Ken Gregory, Prof Bernie xxx and Dr xxx. The projetc aims to develop a major national resource for geomorphology based on interactive web-delivered mapping of the landsdcape of Britain.
2008- Morphodynamics and salmon habitat changes in the braided river Feshie. This work in colaboration with Dr Joe Wheaton (Utah State), Prof James Brasington (Christchurch, NZ) and Stuttgart University Hydraulics lab, combines accurate topographic survey of changes in channel form with 2-D CFD modelling to create the physical habitat dynamics for Atlatnic salmon life stages. The aplication of the CASIMIR fuzzy habitat model enables uncertainty within the habitat preferences of ifferernt lifestages to be accounted or in the modelling.
2008-9 NERC Project on hydraulicsof complex flows over wooded floodplain surfaces (Co-I, Prof Steve Darby PI). This project utilised novel Terrestrial Laser Scanning coupled to Laser-synthing to genreate millimetre accuracte models of complex wooded floodplain surfaces. The Laser-sythed models were then subjectd to controlled flows within the Chilworth Hydraulis Laboratory 21m recirculating and tilting flume. 3-dimensional flow field was mapped over the patch. The results demonstrate the complex nature of 3-D flow patterns over root sytems on the surface of the floodplain, wich in volves localised advection of flows forcd by the root generated micro-topography.
Earth Surface Dynamics
Professor David Sear
University of Southampton University Road Southampton SO17 1BJ Location: 44/2023
Room Number: 44/2023
Telephone: (023) 8059 4614
Facsimile: (023) 8059 3295