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

• Published in: Environmental Research Communications
• Main Authors: Freeman, Mervyn, Lam, Mai Mai
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Science 2019
• Subjects: Antarctic; Antarc*
• Online Access: http://nora.nerc.ac.uk/id/eprint/525285/; https://nora.nerc.ac.uk/id/eprint/525285/1/Freeman_2019_Environ._Res._Commun._1_111007.pdf; https://iopscience.iop.org/article/10.1088/2515-7620/ab4a84

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, By, 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 By 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 By can be expected to persist. Since the tropospheric pressure anomalies causing these winds have been associated with By-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.