A study funded by CPO’s Modeling, Analysis, Predictions, and Projections (MAPP) program, titled: “CMIP5 Model Simulations of the Impacts of the Two Types of El Nino on U.S. Winter Temperature,” was accepted for publication by the Journal of Geophysical Research: Atmospheres.
The work, conducted as a part of MAPP’s CMIP5 Task Force, examined CMIP5 model simulation to examine impacts of the two types of El Niño on the U.S. winter temperatures
By examining 30 CMIP5 model simulations, the researchers concluded that the CMIP5 models are more capable of simulating the observed Eastern Pacific (EP) El Niño impacts on U.S. winter climate but less capable of simulating the observed Central Pacific (CP) El Niño impacts. The cause of this difference in CMIP5 model performance was explained using the tropical Pacific OLR anomalies induced by these two types of El Nino.
Figure 1. The EOF patterns of SSTanomalies calculated from the observations and the CMIP5 models for (a) EP El Niño and (b) CP El Niño. The loading coefficients in the patterns have been scaled by their corresponding eigenvalues to reflect their amplitudes and are in the units of degree Celsius. The patterns are shown in order from the highest to lowest pattern correlation between the observations and modeled U.S. winter air temperature regression patterns.
The study suggests that it will become more challenge for contemporary climate models to simulate or predict the El Nino impacts on U.S. climate after the El Nino changes from the traditional EP type to the emerging CP type.
To view the full research article, visit: http://onlinelibrary.wiley.com/doi/10.1002/2013JD021064/pdf