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Rapid Climate Change (RAPID) programme Meric Srokosz Southampton Oceanography Centre Natural Environment Research Council (NERC). mas@soc.soton.ac.uk http://rapid.nerc.ac.uk. Bermuda Rise marine sediment & Greenland ice core. From Adkins et al. (1997) - high deposition rate 20-100cm/kyr
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Rapid Climate Change (RAPID) programme Meric Srokosz Southampton Oceanography Centre Natural Environment Research Council (NERC) mas@soc.soton.ac.uk http://rapid.nerc.ac.uk
Bermuda Rise marine sediment & Greenland ice core From Adkins et al. (1997) - high deposition rate 20-100cm/kyr Matching the time scales of various palaeo proxies is a problem Records need high temporal resolution and dating accuracy to detect rapid climate change events
Impact of THC collapse in numerical models Temperature change in deg. C if collapse occurs in 2050, mean for first decade relative to pre-industrial (HadCM3) (courtesy Michael Vellinga, Hadley Centre)
Model predictions of THC changes due to global warming Wide range of predictions from different models Uncertainty within models also not well understood
RAPID - Overall objective • RAPID aims to investigate and understand the causes of rapid climate change, with a main (but not exclusive) focus on the role of the Atlantic Ocean’s Thermohaline Circulation (THC) observations paleo data modelling Observational focus on North Atlantic NERC £20M 2001-2008
RAPID funding • 4 Announcements of Opportunity (AO), plus SBRI • Monitoring the Atlantic Meridional Overturning Circulation ~£5M • Specific AO to develop pre-operational “early-warning” system (3 projects) • Working with NSF and NOAA • Joint AO with NWO (Netherlands) & RCN (Norway) • To build on ongoing activities in all three countries, and benefit from a cross-national effort (5 projects) • 1st & 2nd “Science” AO (28 projects) • 2nd AO focus on synthesis / data assimilation of observations • Small Business Research Initiative (4 projects) • Data management ~£1M through NERC data centres
Monitoring the Atlantic MOC • Cannot measure THC per se but can measure the meridional overturning circulation (MOC) and the associated heat transport • Collaboration between NERC - NSF - NOAA • 26.5˚N array Bryden / Cunningham (SOC), Marotzke (MPI, Germany), Johns (Miami) & Baringer (AOML) meridional heat transport, Florida Straits current measurements • Deep Western Boundary Current (DWBC) observations - Hughes (POL) Grand Banks and Halifax arrays & Toole (WHOI) WHOI-Bermuda line • Watson (UEA) autosamplers for 129I • Rossby (URI) Oleander line NY-Bermuda
Monitoring the MOC - 26.5˚N & Deep Western Boundary Current (arrays deployed in 2004) Monitoring locations
DWBC WAVE = Western Atlantic Variability Experiment POL RapidLander BPR Arrays deployed April and August 2004
Boundary signals in altimetry and models Correlation of high pass filtered altimetry everywhere with that averaged in the northern NE Atlantic (marked in black dots). Places where correlation is not significant at the 95% level are left white (Hughes, POL). Williams & Roussenov (Liverpool) are trying to model these boundary signal at the surface and at depth.
26.5˚N monitoring method Gulf Stream transport - Florida Straits cable Ekman transport - using wind climatology Interior geostrophic flow - mooring array Heat transport - XBT sections, CTD sections
Atlantic MOC array at 26.5˚N (deployed Feb/Mar 2004) Western boundary 3 Miami moorings, rest of array SOC moorings
Moored profiler D277/8 U. Miami & SOC mooring teams
ADCP E ADCP W EBH5 EBH4 EBH3 BJ A EBH2 EBH1 WB1 EB3 EB2 EB1 WB2 WBH1 WBH2 BJ B MAR3 MAR1 MAR4 WB4 BJ E MAR2 Complete array as deployed February-March 2004 Currently being recovered and re-deployed (Darwin and Knorr cruises)
D279 SOC cruise to calibrate 26.5N array
Monitoring the Atlantic MOC at 26.5˚N Placing of density profiles MOC OCCAM Estimate FLAME (Hirschi et al. GRL 2003)
Calibrating sediment cores with modern observations Palaeo data from Eirik Ridge sediments on past changes in DWBC Measure DWBC ---- CTD / LADCP sections Geostrophic currents from D230 x = current meter Bacon (SOC) McCave (Cambridge)
Surface fluxes associated with weakening MOC SOC Flux Dataset NAO Composite HadCM3 MOC Weakening Composite Anomalous Heat Flux for 5 year period prior to weakening event Josey et al., 2001, GRL, 28(24), 4543-4546 Josey (SOC)
New model for open ocean deep convection Munk gyre problem. Upper ocean currents caused by the wind stress, and intensified at the western boundary, due to frictional effects. Animation shows the flow adapting finite element grid. (2-D: v-velocity comp.) Pain (Imperial College)
Where next? • MOC observing system seen as key part of N. Atlantic observations by CLIVAR for decadal climate prediction • Recommendation of CLIVAR workshop on Atlantic Predictability 2004 • MOC observing system is funded for 4 years (to 2008) • RAPID will provide proof of concept but to detect significant MOC change requires ….. (longer) • Potential for further funding in UK, but require: • Successful peer reviewed proposal (submitted by early 2006?) • Continued international collaboration (NOAA, NSF) • Links to other international work in N. Atlantic (e.g. MOVE array at 16˚N, ASOF arrays in northern N. Atlantic)