Evolution of seasonal temperature disturbances and solar forcing in the US North Pacific

We analyze the long-term evolution of seasonal temperature disturbances in a 2.5×2.5° area of the US North Pacific. Late Fall and early Winter display significant correlation of temperature disturbances and are investigated in detail. The long-term evolution of the Fall temperature disturbances from 1945 to 2008 closely follows that of solar activity. The robustness of these results is successfully controlled in a 2.5×2.5° area immediately north of the studied region. The modulation of temperature disturbances is very large (∼30%) compared to the corresponding changes in solar irradiance, and has significant variability, even at small geographical scale. The physical mechanism of solar forcing of temperature disturbances remains to be understood, but a relation with cloudiness and influence of the Madden-Julian oscillation in the North Pacific is suggested.