Transcript Images are courtesy of the National Snow and Ice Data Center

Climate response associated with the
Southern Annular Mode in the
surroundings of Antarctic Peninsula
Andrea F. Carril,
Claudio G. Menéndez
and Antonio Navarra
Images are courtesy of the National Snow and Ice
Data Center (NSIDIC), University of Colorado
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Spatial trends of the
Antarctic Sea-Ice Concentration
Monthly Antarctic sea-ice drifts derived from the
SMMR/SSMI over 1979-2000 (Lui et al. 2004)
• Contours are trends [%]
• Left: full trends
• Right: trends after
removing SAM and ENSO
(contours give the trends
due to SAM and ENSO)
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Observed SAM-related variability in SIC
Regression between seasonal SAM index and SIC
(HadISST1), JAS, 1980-1999 (Lefebvre et al. 2004)
• Shadows * 100 are [%]
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Questions marks
• Are the last generation CGCMs representing the SAM-related
variability appropriately?
• Are those models capturing the recent observed warming in
the Antarctic Peninsula region?
• Is it possible to extract an average picture of the SAM-related
variability in a warmer climate?
• Is the cryosphere sending signals about climate change?
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Based on two IPCC experiments
• 20C3M climate of the 20th century: Historical run
• SRES A2 climate change experiment: initial conditions from
end of 20C3M, to 2100
Time slides
• 1970-1999: actual climate
• 2070-2099: future climate
Selected variables
• ST, SLP, near surface wind and sea-ice
• SAM index is the PC-1 geop(500 hPa)
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Models documentation is available at www-pcmdi.llnl.gov
Models
Institution and Country
CNRM CM3
MètèoFrance, France
GFDL CM 2.0
Geophysical Fluid Dynamics Laboratory, USA
GISS ER
Goddard Institute for Space Studies, USA
IPSL CM4
Institut Pierre Simon Laplace, France
MIROC 3. 2 MedRes
Center for Climate System Research, National Institute for
Environmental Studies and Frontier Research Center for Global
Change, Japan
MRI CGCM 2.3.2
Meteorological Research Institute, Japan
NCAR PCM
National Center for Atmospheric Research, USA
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Multi-model ensemble mean, SLP filed
20C3M
SRES A2
SRES A2 minus 20C3M
+ - +
SAM Positive Phase
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Multi-model Control Run
Contours are the multi-model mean
Shadows are the spread
SLP
ST
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SIC
Multi-model Control Run
Control run minus reference climatologies
NCEP (SLP, ST, 1970-1999) and Hadley (SIC, 1982-1999)
SLP
ST
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SIC
Multi-model Annual Mean
Climate Change Projections
Control run minus SRES A2 experiment
Present climate is 1979-1999 while future climate is 2070-2099
SLP
ST
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SIC
Sea ice thickness
Comparison with observations
Image courtesy of Enrico Scoccimarro, INGV
Ice Thickness SINTEXG spring - years 81-130
Ice Draft data
U.S. Navy
submarines
Ice Thickness SINTEXG spring - years 81-130 150 W
Multi-model
SAM-Positive Phase-related variability
• Climate change projects into the positive phase of the SAM in
annual mean conditions
• In present climate SAM is particularly strong during the austral
spring
• In future climate SAM is also strong during the austral spring
(and summer)
We are going to explore into the SAM-PP-related variability
and its change in a warmer climate
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Present climate SAM-PP-related variability
SLP
SW
ST
SIV
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Future climate SAM-PP-related variability
ST
ST
(future conditions)
(present conditions)
SIV
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SIV
Future climate SAM-PP-related variability
SLP
SLP
(present conditions)
(future conditions)
SW
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SW
Conclusions
 We extracted a picture of the response of the SAM to
increasing GHG in a multi-model ensemble produced in the
framework of the 4th IPCC project.
 In mean average, SLP climate change projects into the
positive phase (PP) of the SAM.
 We centered the attention in the surface climate variability
associated with the SAM PP and its change in a warmer
climate.
 Particular attention is on the surroundings of the Antarctic
Peninsula
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Conclusions (cont.)
 Over the present climate slice, the multi-model ensemble
mean reproduce the regional warming around the AP
associated with the SAM.
 When increasing GHG, warming in the neighborhoods of the
AP (and decreasing of sea-ice volume in the sea-ice edge
region) intensifies.
 This result suggests that recent observed sea-ice trend around
the AP could be associated to anthropogenic forcings.
 Surface changes in T and SI are consistent with anomalous
atmospheric heat transport associated with circulation
anomalies.
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Word of warning …
•
The confidence in sea-ice anomalies response is limited by the
reduced number of models that provides the information and the
large inter-model spread.
•
Even if the large scale response to the SAM variability is an
important driver of the AP climate change, in CGCMs the local
interactions between the atmosphere, sea and sea-ice are
misrepresented.
!
If the stratospheric ozone recovers the SAM variability could also
be affected (Shindell and Schmidt 2004).
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
We emphasize that the results need
to be view with caution, given the
weaknesses in the models and the
uncertainties related to the future
evolution of the O3.
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
Following the IPCC schedule…
 March 2005, preliminary results were presented
at IPCC meeting, Hawaii
 May 2005, a manuscript was submitted to GRL
(in revision)
 December 2005, dead-line to
be in press, then to be included in
the IPCC AR4
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra
SAM vs ENSO related variability
Regression maps of SIC (shaded) and T at 2m
(contour) anomalies, 1979-2002 (Lui et al. 2004)
•Left: SAM signal
• Right: ENSO signal
Regression coefficients
indicate changes in SIC [%]
and T [°C] corresponding to
1standard deviation change
in the indices
Andrea F. Carril, Claudio G. Menéndez and Antonio Navarra