rapid climate change (rapid) programme meric srokosz southampton oceanography centre
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Rapid Climate Change (RAPID)
programme
Meric SrokoszSouthampton Oceanography Centre
Natural Environment Research Council (NERC)
mas@soc.soton.ac.uk
http://rapid.nerc.ac.uk
Bermuda Rise marine sediment & Greenland ice coreBermuda 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 problemRecords need high temporal resolution and dating accuracy to detect rapid climate change events
Impact of THC collapse in numerical modelsImpact of THC collapse in numerical models
(courtesy Michael Vellinga, Hadley Centre)
Temperature change in deg. C if collapse occurs in 2050, mean for first decade relative to pre-industrial (HadCM3)
Model predictions of THC changes due to global warmingModel predictions of THC changes due to global warming
Wide range of predictions from different models
Uncertainty within models also not well understood
RAPID - Overall objectiveRAPID - 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)
paleo data
modelling
observations
Observational focus on North Atlantic
NERC £20M2001-2008
RAPID fundingRAPID 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 MOCMonitoring 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 CurrentMonitoring the MOC - 26.5˚N & Deep Western Boundary Current
(arrays deployed in 2004)
Monitoring locations
DWBCDWBC
POL RapidLander BPR
Arrays deployed Apriland August 2004
WAVE = Western Atlantic Variability Experiment
Boundary signals in altimetry and modelsBoundary 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 method26.5˚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)Atlantic MOC array at 26.5˚N (deployed Feb/Mar 2004)
Western boundary3 Miami moorings, rest of array SOC moorings
Moored profiler D277/8Moored profiler D277/8
U. Miami & SOC mooringteams
Complete array as deployed February-March 2004Complete array as deployed February-March 2004
ADCP W
EBH5
EB1EB2
EB3
EBH1
EBH2
EBH3
EBH4
MAR2 MAR1 MAR3MAR4WB4
WB2WBH1
WBH2
WB1
BJ A
BJ BBJ E
ADCP E
Currently being recovered and re-deployed (Darwin and Knorr cruises)
D279D279
SOC cruise to calibrate 26.5N array
Monitoring the Atlantic MOC at 26.5˚NMonitoring the Atlantic MOC at 26.5˚N
Estimate
MOC
Placingof densityprofiles
(Hirschi et al.GRL 2003)
OCCAM
FLAME
Calibrating sediment cores with modern observationsCalibrating sediment cores with modern observations
Geostrophic currents from D230x = current meter
Palaeo data from Eirik Ridge sediments on past changes in DWBC
Measure DWBC
---- CTD / LADCP sections
Bacon (SOC)McCave (Cambridge)
Surface fluxes associated with weakening MOCSurface fluxes associated with weakening MOC
HadCM3 MOC Weakening Composite
SOC Flux Dataset NAO 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 convectionNew 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?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)
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