Seven – eight year oscillatory mode of climate variability 1 and its coherence with geomagnetic activity from 2 stratosphere to troposphere

Phase coherence between geomagnetic activity and temperature vari7 ability from stratosphere to troposphere is quantified and statistically tested in 8 the oscillatory mode with the period 7–8 years using the ERA-40/ERA-Interim 9 and NCEP/NCAR reanalysis monthly air temperature data. Conditional phase 10 coherence is used to identify the North Atlantic Oscillation (NAO) as a mediator 11 transferring the geomagnetic influence from the stratosphere to the troposphere 12 and near-surface air temperature. Cross-frequency phase–amplitude causal cou13 pling is evaluated in daily surface air temperature using the conditional mutual 14 information in order to understand the role of the 7–8 year cycle in the climate 15 variability. Statistically significant causal influence of the phase of the 7–8 year 16 cycle on temperature variability with temporal scales shorter than 12 months is 17 observed. Within a large area of Europe, yearly conditional means of surface air 18 temperature change within the 7–8 year cycle in the range 1.2–1.6 K. 19