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Keywords:

  • dust storm;
  • Arctic Oscillation;
  • weather disturbance;
  • East Asia

Abstract

In this work, the authors investigated the spring dust storm frequency variations in northern China and its relationship with weather disturbances, cold high, eddy kinetic energy (EKE), as well as the impact of the Arctic Oscillation (AO) on the dust storm frequency variations. It is found that there is a significantly decreasing trend of −26%/10 years in the dust storm frequency variations. In addition, the year-to-year variations are also remarkable, which account for 58.3% of the total variance of the dust storm frequency variations. The synoptic variance of 850 hPa height, EKE, and near-surface cold highs are highly correlated with the dust storm frequency variations. During the last 40 years or so, there have been significant trends in synoptic variance, cold-high frequency, and kinetic energy over northern China and Mongolia, which are −3.2, −4.0, and −5.0%/10 years, respectively. The trends are fairly consistent with long-term variations of dust storm frequency. The AO shows good correlation with the interannual variations of the dust storm frequency. This out-of-phase relation is supported by the significantly negative correlations between AO index and eddy growth rate between 850/700 hPa in midlatitude East Asia, implying that AO can modulate weather disturbances and dust storm activities through influencing the atmospheric instability. It is found, however, that the spring AO index shows no evident long-term trend. Land cover changes, global warming, and other climate teleconnections may, at least partly, be responsible for the secular decreasing of dust storm frequency over northern China. Copyright © 2006 Royal Meteorological Society.