Atmospheric circuit influences on ground-level pressure in the Antarctic and Arctic

Abstract

Pressure variations at 11 Antarctic sites and 7 Arctic sites have been examined and show significant correlations with a daily proxy for the output of the meteorological generators of the global atmospheric circuit. This proxy is derived from vertical electric field measurements made at Vostok on the Antarctic ice plateau. Taken with the finding of proportionate pressure variations correlated with atmospheric circuit changes owing to coupling with the interplanetary electric field, particularly for the Antarctic plateau (magnetic latitude > 83°) region, this provides experimental evidence that a small portion of the surface pressure variations are due to the influence of the global atmospheric circuit. The response to the interplanetary electric field is an example of Sun-weather coupling. To evaluate it, the daily average interplanetary magnetic field (IMF) east-west component (B y) is used as a proxy for the north-south interplanetary electric field, which produces opposite ionospheric potential changes in the northern and southern polar caps. The correlation with IMF B y for the pressure variations for the Antarctic sites for a solar cycle (1995-2005) is small (0.9% average covariance for the magnetic latitude > 83° sites) but significant (99.7% confidence level). The Arctic stations show a negative regression between pressure variations and IMF B y, a relationship expected if the linkage process operates by the atmospheric circuit, but it is only found when the interval is restricted to the peak of the sunspot cycle (1999-2002). Copyright 2008 by the American Geophysical Union.