Organic and inorganic bromine compounds and their composition in the Arctic troposphere during polar sunrise
Organic and inorganic bromine compounds and their composition in the Arctic troposphere during polar sunrise
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极地日出期间北极对流层中的有机和无机溴化合物及其组成
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
S. Landsberger
中科院分区：
文献类型：
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作者：
Shao;Y. Yokouchi;L. Barrie;K. Muthuramu;P. Shepson;J. Bottenheim;W. Sturges;S. Landsberger
1992年1月18日至4月21日，在加拿大西北地区阿勒特进行的极地日出实验期间，在对流层中测量了颗粒和气相无机溴、总有机溴和几种单独的有机溴。测量结果显示：（1）溴化物粒子从黑暗时期的约10 ng（Br）m−3逐渐增加到光明时期的>20 ng（Br）m−3，其中120 ng（Br）m−3的显著峰值对应于强烈的O3耗尽事件。(2)无机气态溴（InorgBr）在黑暗期间约为60 ng（Br）m−3，相对稳定。在日出前，一个高达280 ng（Br）m−3的主峰伴随着总有机溴的一个类似峰。这些事件起源于格陵兰上空的自由对流层。日出后，InorgBr的峰值对应于O3耗尽期。InorgBr似乎是HBr、HOBr和Br 2的总和。(3)总有机溴在日出前相对稳定，为100 ng（Br）m−3，但日出后变化较大，高达280 ng（Br）m−3。个别物种包括CHBr 3，含量为7-60 ng（Br）m−3。CH 2Br 2、CH 2ClBr、CHClBr 2和CHCl 2Br的水平较低，为0.5-7.5 ng（Br）m−3。CHBr 3对总有机溴的贡献最大，平均占23%，其余4种平均不到5%。假设浓度为40 ng（Br）m−3（按体积计为万亿分之11），CH 3Br（未测量）应占总有机溴的44%。其余的贡献可能来自“缺失”物种，这些物种在日出后占优势，浓度高达240 ng（Br）m−3，可能包括一些无机物种。日出后有机溴的所有峰对应于O3耗尽事件。(4)CHBr 3、CHClBr 2和CHCl 2Br显著相关。CHClBr 2/CHBr 3比值随In（CHBr 3）的增加而线性下降，日出后下降幅度比日出前大。这种降低表明CHBr 3的破坏速率不同，其速率常数大于CHClBr 2。CHCl_2Br/CHClBr_2比值与In（CHClBr_2）之间存在类似的关系，但暗期斜率接近于零，表明两种物种在光照期的速率差异较大。
Particle and gas phase inorganic bromine, total organic bromine, and several individual organic bromine species were measured in the troposphere during the Polar Sunrise Experiment at Alert, Northwest Territories, Canada, during January 18 to April 21, 1992. The measurements revealed the following: (1) Particle bromide increased gradually from about 10 ng (Br) m−3 during the dark period to >20 ng(Br) m−3 during the light period, with a marked peak of 120 ng(Br) m−3 corresponding to a strong O3 depletion event. (2) Inorganic gaseous bromine (InorgBr) was about 60 ng(Br) m−3 during the dark period and relatively constant. A major peak, up to 280 ng(Br) m−3, before sunrise accompanied a similar peak in the total organic bromine. These episodes originated in the free troposphere over Greenland. After sunrise the peaks in InorgBr corresponded to O3 depletion periods. InorgBr appeared to be the sum of HBr, HOBr, and Br2. (3) Total organic bromine was relatively constant before sunrise at 100 ng(Br) m−3 but more variable afterward, up to 280 ng(Br) m−3. Individual species include CHBr3 with levels of 7–60 ng(Br) m−3. CH2Br2, CH2ClBr, CHClBr2, and CHCl2Br levels were lower at 0.5–7.5 ng(Br) m−3. CHBr3 was the largest contributor to total organic bromine of the five species, on average accounting for 23%, while the other four species amounted to less than 5% on average. CH3Br (not measured) should contribute 44% of total organic bromine assuming a concentration of 40 ng(Br) m−3 (11 parts per trillion by volume). The remaining contribution was probably from ”missing„ species which were episodically dominant after sunrise with concentrations up to 240 ng(Br) m−3 and may include some inorganic species. All the peaks in the organic bromines after sunrise corresponded to the O3 depletion events. (4) CHBr3, CHClBr2, and CHCl2Br were significantly correlated. The ratio CHClBr2/CHBr3 decreased linearly with increasing In(CHBr3), with a steeper decrease after sunrise than before. The decreases suggest different rates of destruction with CHBr3 having a larger rate constant than CHClBr2. A similar relationship existed between the ratio CHCl2Br/CHClBr2 and the In(CHClBr2), but the dark period slope was near zero, indicating a greater difference in rates in the two species in the light period.