First 2 Leading Patterns of Global SST Variabilty with Observed Radiative Forcing

Description: Observed radiative forcing and ozone with sea surface temperature set to the combined first 2 leading patterns (EOF1+EOF1) of SST variability.

Experiment ID: eof1+eof2_sst

Years: 1979-2012

Forcings

Sea Surface Temperature (SST)
First 2 leading patterns (EOF1 and EOF2) of Global SST Variabilty
(click images to enlarge)
The EOF analysis is applied to the detrended monthly global SSTs from January 1978-December 2011. The trend is derived from the linear fit to the 408 monthly values during 1978-2011, calculated at each grid point. The EOFs are calculated from the detrended residual data and are based on the covariance matrix.

For subsequent years after 2011, the detrended monthly Hurrell1 SST data are projected onto the above computed EOF patterns, and the principal component time series is updated appropriately.

For purposes of the model simulations, the SST anomalies associated with the sum of the EOF1 and EOF2 variability are added to the monthly varying climatological SSTs (1979-2010) to produce a total SST field. This field is specified within the domain 60N-60S. Poleward of that domain, SST/sea ice variability is according to the Hurrell analysis, and is identical to that specified in the fully-forced experiments. Likewise, all GHGs concentrations and aerosols evolve as in the fully forced experiments.

1Hurrell, James W., James J. Hack, Dennis Shea, Julie M. Caron, James Rosinski, 2008: A New Sea Surface Temperature and Sea Ice Boundary Dataset for the Community Atmosphere Model. J. Climate, 21, 5145–5153. doi: 0.1175/2008JCLI2292.1
Sea Ice (SIC) Values from dataset described here:

Hurrell, James W., James J. Hack, Dennis Shea, Julie M. Caron, James Rosinski, 2008: A New Sea Surface Temperature and Sea Ice Boundary Dataset for the Community Atmosphere Model. J. Climate, 21, 5145–5153. doi: 0.1175/2008JCLI2292.1
Greenhouse Gases (GHG) Values are from:

Meinshausen, M., S. J. Smith, K. V. Calvin, J. S. Daniel, M. Kainuma, J.-F. Lamarque, K. Matsumoto, S. A. Montzka, S. C. B. Raper, K. Riahi, A. M. Thomson, G. J. M. Velders and D. van Vuuren (2011). The RCP Greenhouse Gas Concentrations and their Extension from 1765 to 2300. Climatic Change (Special Issue). doi: 10.1007/s10584-011-0156-z

which are the CMIP5 Recommendations for annual average, global mean concentrations.
Ozone (03) Data from the AC&C/SPARC ozone database:

Cionni, I., V. Eyring, J. F. Lamarque, W. J. Randel, D. S. Stevenson, F. Wu, G. E. Bodeker, T. G. Shepherd, D. T. Shindell, and D. W. Waugh, 2011: Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing, Atmos. Chem. Phys. Discuss., 11, 10875-10933, doi: 10.5194/acpd-11-10875-2011 , 2011.

Aerosols ECHAM5 uses a built-in, time independent aerosol model which is based on atmosphere layers, and land and water surface types, described here:

Tanre, D., Geleyn, J.-F. and Slingo, J. M. (1984): First results of the introduction of an advanced aerosol-radiation interaction in the ecmwf low resolution global model. In: Aerosols and Their Climatic Effects, edited by Gerber, H. and Deepak, A., pp. 133–177. A. Deepak, Hampton, Va.

CAM4 uses time-varying aerosol content, and volcano aerosols from 1979-2005. After 2005, RCP6 aerosols (with no volcanoes) are used.