The deductio of hydroxyl radical atmospheric background concentration and its seasonam variation by the observation of Cl2C=CCl2 and MeCCl3

• Main Authors: Tsou, Ching-Yuan, 鄒慶源
• Other Authors: Jia-Lin Wang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/28105514935946919681

碩士 === 國立中央大學 === 化學系 === 85 === Hemispheric averaged background mixing ratios of CCl2＝ CCl2 during the period 1988-1996 are reported for the northern and southern hemispheres. These data were generated form the 71N to 46S. Pronounced seasonal variation in the atmospheric abundance of CCl2＝CCl2 was observed in the northern hemisphere with annual maximum in the summer and minimum in the winter, suggesting a strong interplay between hydroxyl radicals and CCl2 ＝CCl2 molecules. Models of different types were developed to deduce the hemisphric average hydroxyl radical abundance and constraining the resulting CCl2＝CCl2 mixing ratios with our observed hemispheric averages, the average hydroxyl radical abundance was deduced to be about 2.3×10^6#/c.c. and the ratio of maximum concentration versus minimum concentration was about 4.1. Modeling of the trend of CH3CCl3 was also performed based on the UCI measurements of CH3CCl3 in the same period as for C2 Cl4. The results were compared with those deduced by the ALE/ GAGE. Excellent agreement was found between these two independent data sets. In this work, we are showing that the availability of more than one data set of CH3CCl3 provides a better constrain on the estimate of hydroxyl radical concentrations.