【來訪單位 Institution】：Stony Brook University  

【邀請人 Host】：Bingbing Wang      【聯絡人 Contact】：Jie LiuSpeaker: Dr. Daniel A. Knopf

Professor, School of Marine and Atmospheric Sciences, Stony Brook University
2003 Ph.D., Swiss Federal Institute of Technology (ETH), Inst. for Atmospheric and Climate Science, Switzerland

Sea spray is a major source of atmospheric aerosol mass over much of the earth’s surface. Knowledge of its composition and cloud formation propensity are critical for determining its role in atmospheric chemistry and climate. In absence of other airborne ice nucleating particles such as mineral dust, sea spray aerosol (SSA) may contribute significantly to atmospheric ice cloud formation. Only recently it has been recognized that SSA is associated with organic matter. SSA particles collected in the field and from laboratory mesocosm experiments are physicochemically characterized using, e.g., scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). These analyses reveal that SSA consist of an inorganic core coated with biogenic material. NEXAFS spectra and spectrophotometric methods based on staining support the presence of polysaccharidic and proteinaceous material stemming from phytoplankton exudate. This exudate material can induce ice formation at tropospheric relevant conditions, providing a link between marine biological activity and cloud formation, thus climate. However, the nature of this marine biogenic material and its physicochemical properties resulting in observed ice nucleating propensities are not well understood and will be discussed in this seminar. 

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* 11:40開始提供簡易午餐，12:00開始講座。老師同學們取餐后請直接到A3-206會議室用餐，等待聆聽報告（可以邊吃邊聽）。

* 請老師同學們訪問MEL網頁（http://mel.xmu.edu.cn/lecture.asp?id=1），在本次午餐會的“報名”一欄填寫信息并提交。

* 本講座將發布當天僅開放給科研人員、技術人員、博士后、訪問學者等教師優先報名，第二天起開放給全體師生報名。學生應在規定時間內報名，如提前以教師的名義報名，將導致報名無效。

* 本周五下午4點為截止報名時間，總報名人數限制在100名以內。如未及時報上名，可于12:00直接到場聽報告。如已報名但因事不能參加，也請在周五下午4點前告知。

* 午餐會一如既往地歡迎大家的關注，如有興趣做講座的老師。歡迎與我聯系。