抄録
Late winter surface pressure anomalies over the North Pacific and North Atlantic fluctuate from year to year in a seesaw. This Aleutian-Icelandic seesaw modulates the upward propagation of planetary waves into the stratosphere, thereby causing year-to-year fluctuations in the ozone layer . We first derive the Aleutian-Icelandic seesaw index from the 40-year re-analyses (ERA-40) compiled at the European Centre for Medium-Range Weather Forecast (ECMWF). February column ozone derived from two decades of satellite ozone observations is then regressed upon the Aleutian-Icelandic index to uncover the seesaw ozone signature. The regression map obtained is contrasted with the ozone regression map associated to the Arctic Oscillation. Both the quasi-stationary and the transient eddy components of ozone are influenced by the seesaw, in a manner consistent with the seesaw imprint upon upper-tropospheric meteorological fields. The year-to-year variations in the February-mean ozone over the Aleutian and Icelandic sectors, which are anti-correlated, are shown to be dominated by the seesaw.
