Figure 10: Bottom panel: schematic conception of atmosphere-ionosphere coupling through the global electric circuit: left panel: for condition of increased air conductivity, right panel: for condition of decreased air conductivity. Upper panel: the differential maps obtained from the GIM GPS TEC data for the period before the Wenchuan earthquake on 12 May 2008. Left panel: 2D distribution obtained on 3 of May 2008, right panel: 2D distribution obtained on 9 May 2008.