蔡锡祺教授学术讲座

       题  目：Airborne Dust, 'the good guy or the bad guy':  how much do we know? 
       主讲人：蔡锡祺（Dr. Si-Chee Tsay）美国国家航空航天局研究员、马里兰大学气象系教授
           （NASA Goddard Space Flight Center, Greenbelt, Maryland, USA）
       时  间：2008年6月25日下午9：30 
       地  点：盘旋路校区综合楼0310室

ABSTRACT

All substances are poisons; there is none, which is not a poison.
The right dose differentiates a poison and a remedy.
P. A. Paracelsus (1493-1541), one of the fathers of modern medicine

       Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena ?African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth’s ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton ?the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth.
       The U.S. Department of Energy Atmospheric Radiation Measurements (ARM) Mobile Facility (DOE/AMF) and ARM Ancillary Facility (AAF/SMART-COMMIT) are currently deploying simultaneously in China during the Asian Monsoon Year (AMY-2008) to acquire comprehensive ground-based observations for aerosol-cloud-water cycle studies. The Phase-I AAF/SMART-COMMIT measurements are taken at Zhangye (39.082° N, 100.276° E, 1461m elevation), China for dust aerosols originating at the Taklimakan and the great Gobi deserts. The AAF is also closely collaborated with the Lanzhou University, China which operates a supersite of Semi-Arid Climate & environment Observatory-Lanzhou (SACOL, 35.95° N, 104.13° E at an altitude of 1966m and ~40km east of Lanzhou city) and a mobile facility of subset SACOL at Jingtai  (37.35° N, 104.01° E at an altitude of 1604m and ~200km north of Lanzhou city). Thus, analyses of simultaneous measurements from these three sites will provide a better understanding of dust properties near different source regions, as well as properties downwind due to mega-city (Lanzhou) influence. To fully characterize the properties of airborne dust near desert regions in the field is an important but challenging task. In this seminar, we will present our recent measurements and retrievals of airborne dust properties.

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                                       大气科学学院   
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