Temporal decrease in upper atmospheric chlorine
Temporal decrease in upper atmospheric chlorine
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DOI：
10.1029/2006gl027600
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发表时间：
2006-12
影响因子：
5.2
通讯作者：
L. Froidevaux;N. Livesey;W. Read;R. Salawitch;J. Waters;B. Drouin;I. MacKenzie;H. Pumphrey;P. Bernath;C. Boone;R. Nassar;S. Montzka;J. Elkins;D. Cunnold;D. Waugh
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文献类型：
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作者：
L. Froidevaux;N. Livesey;W. Read;R. Salawitch;J. Waters;B. Drouin;I. MacKenzie;H. Pumphrey;P. Bernath;C. Boone;R. Nassar;S. Montzka;J. Elkins;D. Cunnold;D. Waugh
我们报告了稳步下降的上部平流层和下部中间层的氯化氢（HCl）的丰度从2004年8月至2006年1月，测量的微波临边探测器（MLS）搭载的光环卫星。对于60°S至60°N的纬向平均值，0.7至0.1 hPa（150至65 km）区域的年平均变化为-27 ± 3 pptv/年，或-0.78 ± 0.08%/年。这与氯源气体的表面丰度下降率（约6至7年前）一致。MLS数据证实，减少全球臭氧消耗工业气体排放的国际协议正在导致全球气态氯总负荷的减少。利用微波着陆系统的数据，现在有可能按季节跟踪平流层的氯化氢变化。在2006年初，平流层总氯（ClTOT）的推断值为3.60 ppbv，（2-sigma）精度估计为7%;在这里研究的18个月期间，平流层氯负荷减少了约43 pptv。我们在其他基于卫星的HCl数据的背景下讨论了MLS HCl测量，以及对地表氯数据的预期。空气的平均年龄为1.55年，年龄谱宽度为2年或更短，与测量结果的总体拟合相当好。
We report a steady decrease in the upper stratospheric and lower mesospheric abundances of hydrogen chloride (HCl) from August 2004 through January 2006, as measured by the Microwave Limb Sounder (MLS) aboard the Aura satellite. For 60°S to 60°N zonal means, the average yearly change in the 0.7 to 0.1 hPa (∼50 to 65 km) region is −27 ± 3 pptv/year, or −0.78 ± 0.08 percent/year. This is consistent with surface abundance decrease rates (about 6 to 7 years earlier) in chlorine source gases. The MLS data confirm that international agreements to reduce global emissions of ozone‐depleting industrial gases are leading to global decreases in the total gaseous chlorine burden. Tracking stratospheric HCl variations on a seasonal basis is now possible with MLS data. Inferred stratospheric total chlorine (ClTOT) has a value of 3.60 ppbv at the beginning of 2006, with a (2‐sigma) accuracy estimate of 7%; the stratospheric chlorine loading has decreased by about 43 pptv in the 18‐month period studied here. We discuss the MLS HCl measurements in the context of other satellite‐based HCl data, as well as expectations from surface chlorine data. A mean age of air of ∼ 5.5 years and an age spectrum width of 2 years or less provide a fairly good fit to the ensemble of measurements.