Microparticle Concentration Within the Dunde Ice Core and itsRelation to Dust Storm and Climate Since the Little Ice Age
LIU Chunping1 YAO Tandong Thompson L. G.2 Davis M. E.2(1 Laborlary of Ice Core and Cold Regions Environment, LIGG, CAS, LanZhou 730000,2 Byrd Polar Research Center, the Ohio State University Columbus O H 43210 U. S. A. )
it is known that insoluble microparticlewithin ice core are associated with the phenomena ofparticle generating, such as large-scale dust storm,volcanic activity, organism activity, and so on.Microparticle analysis may reveal the microparticlesources and dust events, moreover, reveal global andregional climatic records in ice core. Determination ofmicroparticles, 2.0μm, 2.0-2.5μm, 5.04μm indiameter, since the Little Ice Age in the Dunde icecore is presented in this paper. Three increasing andthree decreasing periods are distinguished since 1400AD. Among them the greatest one was in the end ofthe 17th century and the early 18th century. A comparison between microparticle concentration and climaticdata since the Little Ice Age confirms that there werethree increasing and decreasing periods. The higherthe microparticle concentration, the colder and drierthe climate; the lower the microparticle concentrationthe warmer and wetter the climate. There exists agood relationship between the concentration ofmicroparticles and dust storm frequency. Most of thematerial deposited on the Dunde ice cap is thoughtoriginated in the surrounding arid and semi--arid areas, probably transported by the dust storms movinginto the Qilian Mountains. When microparticle concentrations appear special values, dust storms wouldhappen and a good relationship presents betweenmicroparticle concentrations and the scale, frequency,intensity of the dust storms, as well as the intensity ofwind. The concentration of total microparticles ( 2.0μm in diameter) for the upper 4--meter ice core is plotted against water--equivalent depth. Seasonal variationis obviously shown. Analyzing microparticles of different sizes, we can see that microparticle variation has acycle of about 200 a.