Why do dust storms decrease in northern China concurrently with the recent global warming?

Abstract

Recent studies have shown that the spring dust storm frequency (DSF) in northern China exhibits an obvious downward trend over the past 50 years concurrently with the recent global warming. We found that the decline of DSF is significantly correlated with the increase of the surface air temperature (SAT) in the region of 70°E-130°E, 45°N-65°N around Lake Baikal, where anthropogenic forcing induces prominent warming in the recent decades. Corresponding to the SAT rise in this region, an anomalous dipole circulation pattern is found in the troposphere that consists of a warm, anti-cyclone centered at 55°N and a cold cyclone centered around 30°N. The DSF is positively correlated to the activity of Mongolian cyclones. The warming trend around Lake Baikal possibly induces a weakening of the westerly jet stream and the atmospheric baroclinicity in northern China and Mongolian regions, which suppress the frequency of occurrence and the intensity of the Mongolian cyclones and result in the decreasing DSF in North China. This mechanism will likely further reduce the spring DSF in the future global warming, scenario. Copyright 2008 by the American Geophysical Union.