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Abstract:
We present a two-decade study with DMSP observations of magnetospheric energy input into the magnetosphere-ionosphere (MI) system during magnetic storms with different intensities for interhemispheric comparisons. DMSP observations are for Poynting flux, electron precipitation, and proton precipitation, all with resolution of 1 second. A smoothing Savitzky-Golay filter is applied to all the data to eliminate possible biases caused by data spikes. More than 300 magnetic storms are grouped with respect to storm intensity (weak to extreme), seasons, and local time. Our data only comprise simultaneous observations in both hemispheres for all events to allow for a more concise inter-hemispherical comparison of the results (“bow-tie” diagrams). We report that climatological studies, i.e., long-term observations, show that the northern hemisphere has a slight preference to receive magnetospheric energy during storms in comparison to the southern hemisphere. This result is consistent with previous observations, but the level of preference here is lower than what has been reported before. We also show that such slight symmetry is broken when short term drivers (IMF By and local time variations), and mid-term variations (seasons and solar cycle), act upon the magnetosphere-ionosphere system. Some implications for the future NASA’s GDC (Geospace Dynamics Constellation) mission will be presented as well.
