Seasonality of Northern Hemisphere Temperatures

What is it about?

Winter, summer, and transitional months (November, December and April) characterize the seasonality of Northern Hemisphere temperature for the 1890–2010 period. The physical mechanisms behind this seasonality are identified. Extreme and outlier years are highlighted and discussed.

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Why is it important?

1. This is the first visual synthesis in a single plot of the major features of the monthly temperature anomaly time series for the Northern Hemisphere. 2. Two uncorrelated factors underlie the observed temperature anomaly seasonality: the North Atlantic thermohaline circulation and the cold ocean-warm land pattern 3. The North Atlantic thermohaline circulation statistically determines the anomality of summers 4. The cold ocean-warm land pattern statistically determines the anomality of winters 5. Extreme and outlier years occur as a dynamical response to the interannual effect of the El Niño Southern Oscillation, the Arctic Oscillation/North Atlantic Oscillation mode and the volcanism, coupled to the long-term temperature trend

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