Thursday, March 29, 2007
The future climate of the North Pacific - from IPCC AR4 model projection
The major mode of variability in North Pacific sea surface temperature (SST) fields is studied based on model control runs and 20c3m simulations. Among the 22 models available at the PCMDI archive center, 18 have complete archives for the pre-industrial control run (PIcntrl), the 20th century climate simulation (20c3m) and the forecast for 21st century under the A1B scenario. Based on spatial pattern correlations, power spectrum analysis of the corresponding PC series, we find that 10 models replicate the major structure in the leading mode of the decadal SST variation, the Pacific Decadal Oscillation (PDO), in their 20c3m and control run simulations. This exercise indicates that a subset of the IPCC models which are validated against 20th century data form a more reliable basis for future climate projections. A projection based on this sub-set of models (10) showing that the leading mode of the Pacific SST in the 21st century will be a uniform upward trend pattern, while PDO stays as the 2nd leading mode under the moderate A1B scenario. James E. Overland of NOAA's
Pacific Marine Environmental Laboratory
has contributed to this work.
Muyin Wang is a Research Meteorologist at NOAA's Pacific Marine Environmental Laboratory and a researcher at the Joint Institute for the Study of the Atmosphere and Ocean (JISAO).