Zenith scattered light measurement: observations of BrO and OClO
Zenith scattered light measurement: observations of BrO and OClO
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DOI：
10.1080/01431161.2010.542621
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发表时间：
2011-12
影响因子：
3.4
通讯作者：
G. Meena;P. Devara
中科院分区：
文献类型：
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作者：
G. Meena;P. Devara
利用差分光学吸收光谱（DOAS）技术，首次在普纳（18° 31′ N，73° 55′ E）观测了平流层BrO和OClO。差分光密度（DOD）拟合技术用于正确选择合适的光谱区域进行分析，以最大限度地减少干扰和不良拟合吸收特征，并最大限度地减少拟合残差。O_3、NO_2、BrO、OClO、O_4、Rayleigh和Ring的观测DOD与计算的DOD吻合较好，DOD的变化百分比分别为0.5%、0.8%、0.15%、0.13%、1.5%、1.2%和1.3%。氯和溴物种在臭氧消耗中发挥着重要作用，因此O3、NO2、BrO和OClO斜柱密度（SCD）是在76°和94°太阳天顶角（SZA）之间推导出来的。在有足够BrO和OClO存在的黄昏期（即90° ~ 94° SZA），O_3的SCD降低。2008年4月1日至6月31日期间，通过紫外/可见光谱法、布鲁尔光谱法和基于卫星的大气制图扫描成像吸收光谱仪（SCIAMACHY）获得了浦那和高纬度站坎普尔（26° 28′ N，80° 24′ E）的O3、NO2、BrO和OClO的总柱密度（TCD）。浦那上空O3和NO2 TCDs的日变化大于坎普尔上空。普纳上空的溴氧TCDs在1.9 × 1013和4 × 1013分子cm−2之间变化，这是由紫外/可见光谱法得出的，而高海拔站坎普尔的TCDs在0.5 × 1013和3.5 × 1013分子cm−2之间变化，这是由科学家得出的。OClO的TCDs在上述期间有增加的趋势，变化范围在2 × 1013和4.5 × 1013分子cm-2之间。
Stratospheric BrO and OClO observations have been made for the first time over a tropical station, Pune (18° 31′ N, 73° 55′ E) using a Differential Optical Absorption Spectroscopy (DOAS) technique by measuring zenith sky scattered light spectra in the wavelength range of 346–358 nm by ultraviolet (UV)/visible spectrometer. The Differential Optical Density (DOD) fitting technique is applied for the right selection of a suitable spectral region for the analysis to minimize interference and poorly fitting absorption features, and also to minimize the residual of the fit. Observed DODs of O3, NO2, BrO, OClO, O4, Rayleigh and Ring are well fitted with the calculated DODs and the percentage DODs are found to vary up to 0.5%, 0.8%, 0.15%, 0.13%, 1.5%, 1.2% and 1.3% respectively. Chlorine and bromine species play an important role in the ozone depletion, hence O3, NO2, BrO and OClO Slant Column Densities (SCDs) are derived between 76° and 94° Solar Zenith Angles (SZAs). The SCDs of O3 are found to be decreased in the twilight period (i.e. between 90° and 94° SZA) in the presence of sufficient BrO and OClO. Total Column Densities (TCDs) of O3, NO2, BrO and OClO are derived by UV/visible spectrometry, Brewer spectrometry and satellite-based Scanning Imaging Absorption spectrometer for Atmospheric Cartography (SCIAMACHY) for Pune and the higher latitude station Kanpur (26° 28′ N, 80° 24′ E) during the period 1 April–31 June 2008. The day-to-day variations in O3 and NO2 TCDs over Pune are found to be more than over Kanpur. BrO TCDs vary between 1.9 × 1013 and 4 × 1013 molecules cm−2 over Pune, which are derived by UV/visible spectrometry, while they vary for the high-altitude station Kanpur between 0.5 × 1013 and 3.5 × 1013 molecules cm−2 derived by SCIAMACHY. The OClO TCDs are found to have an increasing trend with variations between 2 × 1013 and 4.5 × 1013 molecules cm−2 during the above period.