Trends in the surface meridional temperature gradient

Abstract

Given the presence of a meridional temperature gradient (MTG) across midlatitudes, largescale eddies transport heat poleward, thereby shaping Earth's climate. Defining an MTG index here as the difference in surface temperature between the 30°-35°N belt and the 50°-55°N belt, we use a temperature record compiled from observations over a 110-year period to determine a trend in the MTG in the last century. We find a significant decreasing trend in the MTG over this period of 0.4 ± 0.1°C per 100 years, along with indications of substantial multidecadal variability. Copyright 1997 by the American Geophysical Union.