NORTH-ATLANTIC OSCILLATION DYNAMICS RECORDED IN GREENLAND ICE CORES

Carefully selected ice core data from Greenland can be used to reconst ruct an annual proxy North Atlantic oscillation (NAO) index. This inde x for the past 350 years indicates that the NAO is an intermittent cli mate oscillation with temporally active (coherent) and passive (incohe rent) phases. No indication for a single, ;persistent, multiannual NAO frequency is found. In active phases, most of the energy is located i n the frequency band with periods less than about 15 years. In additio n, variability on time scales of 80 to 90 years has been observed sinc e the mid-19th century.