Regional, seasonal, and inter-annual variations of Antarctic and sub-Antarctic temperature anomalies related to the Mansurov effect

Abstract

Abstract We use National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data to show that Antarctic surface air temperature anomalies result from differences in the daily-mean duskward component, B y , of the interplanetary magnetic field (IMF). We find the statistically-significant anomalies have strong geographical, seasonal, and inter-annual variations. For the interval 1999–2002, regional anomalies poleward of 60°S are of diminishing representative peak amplitude from autumn (3.2 °C) to winter (2.4 °C) to spring (1.6 °C) to summer (0.9 °C). Exploiting apparently simplifying properties in the sub-Antarctic region in autumn 1999–2002, we demonstrate that temperature anomalies in this case are due to geostrophic wind anomalies, resulting from the same B y changes, moving air across large meridional gradients in zonal mean air temperature between 50 and 70°S over the 7-hour timescale for which a change in B y can be expected to persist. Since the tropospheric pressure anomalies causing these winds have been associated with B y -driven anomalies in the electric potential of the ionosphere, we conclude that IMF-induced changes to the global atmospheric electric circuit can cause day-to-day changes in regional surface air temperature of up to several degrees Centigrade.