Modeling the Pattern of Tropical Ocean Warming

Authors Shin and Sardeshmukh (2011) note that there is increased interest in the ability of climate models to simulate and predict surface temperature and precipitation changes on sub-continental scales," and they state that these regional trend patterns "have been strongly influenced by the warming pattern of the tropical oceans," which suggests that correctly simulating the warming pattern of the tropical oceans is a prerequisite for correctly simulating sub-continental-scale warming patterns.

In exploring this subject further, Shin and Sardeshmukh compared multi-model ensemble simulations of the last half-century with corresponding observations, focusing on the world's tropical oceans, as well as the land masses surrounding the North Atlantic Ocean, including North America, Greenland, Europe, and North Africa. This was done, as they describe it, using "all available coupled [atmosphere-ocean] model simulations of the period 1951-1999 from 18 international modeling centers, generated as part of the IPCC's 20th century climate simulations with prescribed time-varying radiative forcings associated with greenhouse gases, aerosols, and solar variations."

The two researchers determined that "the tropical oceanic warming pattern is poorly represented in the coupled simulations," and they say that their analysis "points to model error rather than unpredictable climate noise as a major cause of this discrepancy with respect to the observed trends." And because of this problem, they found that "the patterns of recent climate trends over North America, Greenland, Europe, and North Africa are generally not well captured by state-of-the-art coupled atmosphere-ocean models with prescribed observed radiative forcing changes."

Shin and Sardeshmukh state that "the fact that even with full atmosphere-ocean coupling, climate models with prescribed observed radiative forcing changes do not capture the pattern of the observed tropical oceanic warming suggests that either the radiatively forced component of this warming pattern was sufficiently small in recent decades to be dwarfed by natural tropical SST variability, or that the coupled models are misrepresenting some important tropical physics." And since the greenhouse-gas forcing of climate "in recent decades" is claimed by climate alarmists to have been unprecedented over the past millennium or more, it would appear that the models are indeed "misrepresenting some important tropical physics."