The model solves the equations of mass, energy, momentum and moisture and it calculates radiative fluxes, surface fluxes, latent heat and cloud cover. The control run is represented by a five-year simulation of the modern climate. Change in annual surface air temperature due to colder North Pacific. Blues indicate a decrease and yellows and reds an increase. Change in percentage annual snow cover due to colder North Pacific.
Blues indicate a decrease and yellows and reds an increase.
In contrast to the earlier experiment in which only North Atlantic SSTs were cooled and a downstream effect over land was noted, here the cooling extends throughout the northern hemisphere. The key element in explaining the meteorological processes that cause the signal in the North Pacific to propagate around the globe is water vapor. The colder SSTs cause evaporation from the ocean's surface to decrease. Thus, drier air blows across the North Pacific, and evaporation over North America also decreases. A decrease in precipitation over the northern hemisphere ocean also occurs, and there is less latent heat release, which cools the atmosphere.