Seasonal variations of dust record in the Muztagata ice cores

Based on the oxygen isotope ratio and microparticle record in ice cores recovered at Mt. Muztagata, Eastern Pamirs, the seasonal variations of atmospheric dust have been reconstructed for the past four decades. High dust concentrations and coarser particle grains have the similar trend with oxygen isotope value. Our statistical results indicate that 50%–60% high dust concentration samples occur during the season with high oxygen isotope values (summer), while low dust storm frequency during spring and winter. Back-trajectory analysis shows that the air mass hitting Muztagata predominately came from West Asia (such as Iran-Afghanistan Plateau) and Central Asia, which are the main dust source area for Muztagata. Dust storms in those source areas most frequently occur during summer (from May to August), while frequent dust storm events in northern China mainly occur during spring (March to May). Regions in the path of Asian dust transport, such as in Japan, the North Pacific, and Greenland, also show high dust concentrations during spring (from March to May). Our results indicate that dust storms have different seasonality in different regions within Asia. Supported by the National Basic Research Program (Grant No. 2005CB422004) and the National Natural Science Foundation of China (Grant Nos. 40571038, 40121101 and 40301009)