The 11-year solar cycle affects the intensity and annularity of the Arctic Oscillation

We investigate the dependence of the Arctic Oscillation (AO) in winter on the solar activity by stratifying the data into overlapping intervals defined by percentiles of the 10.7 cm radio flux. The AO exhibits a complex dependence of its polarity, being weakest under low, but not minimum, solar activity, while strongest in solar maxima. The AO is more/less variable (i.e., more/less active) under a high/low solar activity. Under a moderate solar activity, its Pacific centre weakens and eventually disappears. These effects seem to be real in spite of a potential for mixing the AO with the second principal component due to sampling errors caused by insufficient spacing between the first two eigenvalues. The weakening of the Pacific centre is not a result of coincidence with major volcanic eruptions or specific phases of the El Niño-Southern Oscillation.