A composite study of the synoptic differences between major and minor dust storm springs over the China-Mongolia areas

1 Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan, ROC 2 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou, China 3 Inner Mongolia Autonomous Region Meteorological Administration, Hohhot, China * Corresponding author address: Prof. Chung-Ming Liu, Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan, ROC; E-mail: liucm@ntu.edu.tw In order to improve the understanding of the mean circulations of and the differences between major and minor dust storm springs over the ChinaMongolia area, multiple-cases, multiple-element circulation composite analyses were conducted utilizing the NCEP/NCAR reanalysis gridded data. The main conclusions are: 1) Based on the differences in the dust storminducing system, dust origin, route of cold air and main dust storm-hit areas, the China-Mongolia dust storms regime can be divided into west, east and Southwest China-Mongolia sub-regimes; 2) During the major dust storm springs in Western China-Mongolia, circulations on the mid-and lowerlevels are characterized by a deeper and stronger Siberian high, dominant troughs or cyclones in and around Mongolia, and intensified westerly winds around the China-Mongolia border, with cold air moving frequently along northwestern or northern routes into China. During minor dust storm springs in Western China-Mongolia, the pattern is altered toward lesser cold air intrusions; 3) During major dust storm springs in Eastern ChinaMongolia, circulations on the midand lower-levels are characterized by the dominant China-Mongolia ridges and troughs or cyclones in and around the Japan Sea, with cold air moving frequently along northeast routes into China; 4) The inter-annual and inter-decadal variations in dust storm occurrences in the last five decades are related closely to the changes in synoptic circulations; and 5) Warming in Mongolia and Southwest Siberia are <Back to Index>