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Original Research Papers

The effect of internal variability on anthropogenic climate projections

Authors:

Asgeir Sorteberg ,

Bjerknes Centre for Climate Research, University of Bergen, Allègaten 70, N-5007 Bergen, NO
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Nils Gunnar Kvamstø

Geophysical Institute, University of Bergen, Norway Bjerknes Centre for Climate Research, University of Bergen, NO
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Abstract

A single model ensemble of five members, with a CO2 increase of 1% per year, has been used to investigate the spread in climate change estimates. It is furthermore explored how this spread is related to internal variability of the climate system and the strength of the CO2 forcing. As expected, the fraction of the globe where a statistically significant climate change could be detected increased with the strength of the CO2 forcing. For temperature this fraction increased rapidly with integration time, while the increase of areas with statistically significant precipitation change was much slower. It is shown that increasing the averaging periods for estimating climate change from 20 to 40 yr reduced the spread due to internal variability by 40% in the Arctic regions. This is due to better sampling of decadal internal variability. In order to reduce sampling uncertainty below a fixed threshold, the number of ensemble members needed is much larger in the polar region than in the lower latitudes. This should be taken into account when designing modelling strategies (high-resolution modelling versus larger number of ensemble members) to reduce uncertainty in future polar climate change. At the time of doubling of CO2, the variance of the climate change estimates, based on 20 yr averages from a single model ensemble, constitutes 13% and 42% of corresponding multimodel ensemble variances for temperature and precipitation, respectively. In the case of precipitation, this indicates that some caution should be used in attributing different climate change estimates to differences in model formulations.

How to Cite: Sorteberg, A. and Kvamstø, N.G., 2006. The effect of internal variability on anthropogenic climate projections. Tellus A: Dynamic Meteorology and Oceanography, 58(5), pp.565–574. DOI: http://doi.org/10.1111/j.1600-0870.2006.00202.x
  Published on 01 Jan 2006
 Accepted on 27 Jun 2006            Submitted on 25 Nov 2005

References

  1. Bentsen , M. , Drange , H. , Furevik , T. and Zhou , T. 2004 . Simulated vari-ability of the Atlantic meridional overturning circulation . Clim. Dyn ., 22 , 701 – 720 .  

  2. Bleck , R. , Rooth , C. , Hu , D. M. and Smith , L. T. 1992 . salinity-driven thermocline transients in a wind-forced and thermohaline-forced isopycnic coordinate model of the north-Atlantic . J. Phys. Oceanogr . 22 , 1486 – 1505 .  

  3. Collins , M. , Botzet , M. , Carril , A. , Drange , H. , Jouzeau , A. and co-authors. 2006 . Interarmual to decadal climate predictability: a multi-perfect-model-ensemble study . J. Climate 19 ( 7 ), 1195 - 1203.  

  4. Covey , C. , AchutaRao , K. M. , Cubasch , U. , Jones , P. , Lambert , S. J. and co-authors. 2003. An overview of results from the Coupled Model Intercomparison Project . Global Planet. Change 37 , 103 – 133 .  

  5. Déqué , M. , Dreveton , C. , Braun , A. , Cariolle , D., 1994 . The ARPEGE/IFS Atmosphere Model: a contribution to the French Climate Mod-elling Community . Clim. Dyn . 10 , 249 – 266 .  

  6. Doblas-Reyes , E J. , Deque , M., Valero , E and Stephenson , D. B. 1998 . North Atlantic wintertime intraseasonal variability and its sensitivity to GCM horizontal resolution. Tellus 50A , 573 – 595 .  

  7. Dutay , J. C. , Bullister , J. L. , Doney , S. C. , On , J. C. , Najjar , R. and co-authors. 2002. Evaluation of ocean model ventilation with CFC-11: comparison of 13 global ocean models . Ocean Model . 4 , 89.  

  8. Furevik , T. , Bentsen , M. , Drange , H. , Kindem , I. K. T. , Kvamsto , N. G. and co-authors. 2003. Description and evaluation of the Bergen climate model: ARPEGE coupled with MICOM . Clim. Dyn . 21 , 27 – 51 .  

  9. Giorgi , E , Hewitson , B. Christensen , J. Hulme , M. von Storch , H. Giorgi , E , Hewitson , B. Christensen , J. Hulme , M. von Storch , H. and co-authors . 2001. Regional Climate Information: Evalua-tion and Projections (Chapter 10). In Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the IPCC (eds J. T. Houghton , Y. Ding , D. J. Griggs M. Noguer , P. J. van der Linden X. Dai , K. Maskell and C. A. Johnson ) Cambridge University Press , Cambridge , pp. 739 – 768 .  

  10. Gao , Y. Q. , Drange , H. and Bentsen , M. 2003 . Effects of diapycnal and isopycnal mixing on the ventilation of CFCs in the North Atlantic in an isopycnic coordinate OGCM . Tellus 55B , 837 – 854 .  

  11. Hibler , W. D. 1979 . Dynamic Thermodynamic Sea Ice Model . J. Phys. Oceanogr . 9 , 815 – 846 .  

  12. Houghton , J. T. , Ding , Y. , Griggs , D. J. , Noguer , M., vander Linden , P. J. , DAI , X. , Mashell , K. and Johnson , C. A. 2001 . Climate Change 2001: The Scientific Basis . Cambridge University Press , p. 881 .  

  13. Johannessen , O. M. , Bengtsson , L. , Miles , M. W. , Kuzmina , S. I. , Semenov , V. A. and co-authors. 2004 . Arctic climate change: ob-served and modelled temperature and sea-ice variability. Tellus 56A , 328 – 341 .  

  14. Kuzmina , S. I. , Bengtsson , L. , Johannessen , O. M. , Drange , H. , Bobylev , L. P. and Miles , M. W. 2002 . The North Atlantic Oscillation and greenhouse-gas forcing. Geophys. Res. Lett . 32 ( 4 ), L04703 , DOI: https://doi.org/10.1029/2004GL021064 .  

  15. Kvamstø , N. G. , Skeie , P. and Stephenson , D. B. 2004 . Impact of Labrador sea-ice extent on the North Atlantic oscillation . Int. J. Cli-matol . 24 , 603 – 612 .  

  16. Lopez , P. , Schmith , T. and Kaas , E. 2000 . Sensitivity of the Northern Hemisphere circulation to North Atlantic SSTs in the ARPEGE cli-mate AGCM. Clim. Dyn . 16 , 535 – 547 .  

  17. Meehl , G. A. , Boer , G. J. , Covey , C. , Latif , M. and Stouffer , R. J. 2000 . The Coupled Model Intercomparison Project (CMIP). Bull. Am. Me-teor. Soc . 81 , 313 – 318 .  

  18. Nilsen , J. E. O. , Gao , Y. , Drange , H. , Furevik , T. and Bentsen , M. 2003 . Simulated North Atlantic-Nordic Seas water mass exchanges in an isopycnic coordinate OGCM. Geophys. Res. Lett . 30 ( 10 ), 1536 , DOI: https://doi.org/10.1029/2002GL016597 .  

  19. Otterå O. H. , Drange , H. , Bentsen , M. , Kvamsto , N. G. and Jiang , D. 2003 . The sensitivity of the present-day Atlantic meridional overturn-ing circulation to freshwater forcing . Geophys. Res. Lett . 30 ( 17 ), 1898 , DOI: https://doi.org/10.1029/2003GL017578 .  

  20. Otterå O. H. , Drange , H. , Bentsen , M. , Kvamsto , N. G. and Jiang , D. B. 2004 . Transient response of the Atlantic meridional overturning circulation to enhanced freshwater input to the Nordic Seas-Arctic Ocean in the Bergen climate model . Tellus 56A , 342 – 361 .  

  21. Räisänen , J. 2001. CO2-induced climate change in CMIP2 experiments: Quantification of agreement and role of internal variability. J. Climate 14 , 2088 – 2104 .  

  22. Räisänen 2002 . CO2-induced changes in interannual temperature and precipitation variability in 19 CMIP2 experiments . J. Climate 2395 – 2411 .  

  23. Semtner , A. J. 1976 . Model For Thermodynamic Growth Of Sea Ice In Numerical Investigations Of Climate. J. Phys. Oceanogr . 6 , 379 – 389 .  

  24. Sorteberg , A. , Furevik , T. , Drange , H. and Kvamsto , N. G., 2005 . Effects of simulated natural variability on Arctic temperature projections . Geophys. Res. Lett . 32 ( 18 ), L18708 , DOI: https://doi.org/10.1029/2005GL023404 .  

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