oceanic circulation role in the ongoing warming hiatus - matt england.pdf · • mk3l model in...
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Oceanic circulation role in the ongoing warming hiatus
Matthew England and (many) collaborators Climate Change Research Centre (CCRC)
and ARC Centre of Excellence for Climate System Science The University of New South Wales
www.science.unsw.edu.au/~matthew
Interdecadal Pacific/Atlantic Ocean variability and the ongoing warming ‘hiatus’
Matthew England and (many) collaborators Climate Change Research Centre (CCRC)
and ARC Centre of Excellence for Climate System Science The University of New South Wales
www.science.unsw.edu.au/~matthew
PACIFIC DRIVER??
ATLANTIC DRIVER??
A century of global climate change and variability….
El Nino / La Nina events have a significant impact…..
El Nino / La Nina events have a significant impact…..
Recent Pacific Ocean trends A century of interdecadal
Pacific variability….
Recent Pacific Ocean trends A century of interdecadal
Pacific variability….
Recent climate trends….
1992-2011 ERA-Interim SLP and wind stress trends
England et al. 2014
Recent climate trends….
1992-2011 AVISO sea surface height trends
England et al. 2014
Recent climate trends….
1992-2011 HadISST sea surface temperature trends
England et al. 2014
Recent surface trends. Sea surface temperature (shading) from NOAA OISST11 and
surface wind velocity (arrows) from ERA interim12. Trends are evaluated with monthly anomalies from January 2001 to October 2013 and scaled to ten-year changes.
2001-2013 trends
Recent climate trends….
1992-2011 GISS surface air temperature trends
England et al. 2014
Australian context?
Recent Pacific Ocean trends….
England et al. 2014
How anomalous is the trade wind acceleration….?
England et al. 2014
How anomalous is the trade wind acceleration….?
England et al. 2014
What do the Pacific wind trends do in models….?
OCEAN GCM, SIMPLE ATMOSPHERE
What does this mean for climate projections….?
England et al. 2014
What does this mean for climate projections….?
England et al. 2014
Projections of a rebound in warming out of the current hiatus
Matthew England and (many) collaborators Climate Change Research Centre (CCRC)
and ARC Centre of Excellence for Climate System Science The University of New South Wales
www.science.unsw.edu.au/~matthew
SAT and SST TRENDS 2013-2030
PACIFIC TEMPERATURE TRENDS 2013-2030
DEPT
H
LONGITUDE
A REVERSAL OF CIRCULATION AND T ANOMALIES SEEN DURING THE HIATUS
What about the role of the Atlantic?
Perspective on Chen and Tung (2014) Science
What about the role of the Atlantic?
Chen and Tung (2014) Science
ATLANTIC OCEAN HEAT CONTENT TRENDS
ATLANTIC
HIATUS 14 YEARS ACCELERATING 14 YEARS
What about the role of the Atlantic?
Estimated change in SST due to a shutdown in the AMOC
Rahmstorf (2002)
What about the role of the Atlantic?
Freshwater forcing
NADW overturning
Freshwater forcing
NADW overturning
Global mean SAT
Freshwater forcing
NADW overturning
Global mean SAT
Anomalies in SST and SSS during an Atlantic hiatus
What about the role of the Atlantic?
NA SST
NA SSS
What about the role of the Atlantic?
Conclusions
• Recent observed trade wind trend unprecedented
Conclusions
• Recent observed trade wind trend unprecedented
• Beyond the variability seen in CMIP models
Conclusions
• Recent observed trade wind trend unprecedented
• Beyond the variability seen in CMIP models
• Cooling impact can account for the hiatus • Ocean heat uptake • Teleconnections from cool East Pacific SST
Conclusions
• Recent observed trade wind trend unprecedented
• Beyond the variability seen in CMIP models
• Cooling impact can account for the hiatus • Ocean heat uptake • Teleconnections from cool East Pacific SST
• Hiatus could persist for much of the present decade
• Warming out of hiatus likely rapid and likely to be +ve IPO-like
Conclusions
• North Atlantic hiatuses are associated with a cooler SST and fresh SSS in the North Atlantic
Conclusions
• North Atlantic hiatuses are associated with a cooler SST and fresh SSS in the North Atlantic
• Required SSS anomalies are >> observed
Conclusions
• North Atlantic hiatuses are associated with a cooler SST and fresh SSS in the North Atlantic
• Required SSS anomalies are >> observed
• Present warming hiatus has a NA climate that contributes to +ve SAT anomalies
Oceanic circulation role in the ongoing warming hiatus
Matthew England and (many) collaborators Climate Change Research Centre (CCRC)
and ARC Centre of Excellence for Climate System Science The University of New South Wales
www.science.unsw.edu.au/~matthew
What impact would the observed Pacific wind trends have in models….?
1. In an OGCM/EBM 2. In a coupled climate model
Pacific wind trends added to both an OGCM and a coupled climate model
1. In the UVic ICCM (2° and ¼° OGCMs)
2. In the CSIRO Mk3L coupled model (~1.7° OGCM)
Ocean model experiments
• UVic / MOM model in global configuration • 3D ocean GCM, EBM atmosphere • Dynamic/thermodynamic sea-ice • Model solutions integrated for 1000+ yrs • Experimental design:
• Control climatological unperturbed experiment • Trade wind trends applied
Climate model experiments
• Mk3L model in global configuration • 3D ocean GCM, 3D atmosphere • Dynamic/thermodynamic sea-ice • Model solutions integrated for 1000+ yrs • Experimental design:
• Control climatological unperturbed experiment • Trade wind trends applied
Coupled model captures ocean heat uptake and teleconnections
What does this mean for climate projections….?
What about past hiatus periods?
What do the Pacific wind trends do in models….?
OCEAN GCM, SIMPLE ATMOSPHERE
What do the Pacific wind trends do in models….?
OCEAN GCM, SIMPLE ATMOSPHERE
What do the Pacific wind trends do in models….?
OCEAN GCM, SIMPLE ATMOSPHERE
What do the Pacific wind trends do in models….?
SPIN UP
OCEAN GCM, SIMPLE ATMOSPHERE
Half the hiatus
What about the role of the Atlantic?
What’s happened in 2014?
Chen and Tung (2014) Science
What about the role of the Atlantic?
