Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements
Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements
复制标题
用于大气图表临散射测量的扫描成像吸收光谱仪显示平流层下部一氧化溴的纬度和垂直分布
DOI：
10.1029/2005jd006479
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发表时间：
2006
影响因子：
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通讯作者：
J. Frerick
中科院分区：
文献类型：
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作者：
C. Sioris;L. Kovalenko;C. McLinden;R. Salawitch;M. Roozendael;F. Goutail;M. Dorf;K. Pfeilsticker;K. Chance;C. Savigny;Xiong Liu;T. Kurosu;J. Pommereau;H. Bösch;J. Frerick
[1]利用SCIAMACHY的地球仪临边散射资料反演了平流层15-30 km范围内一氧化溴（BrO）的垂直廓线。与球载SAOZ-BrO和LPMA/DOAS仪器的首次验证比较表明，反演偏差为± 20%或更小。消除光谱拟合不确定性后，在25 km处的2 km网格上精度接近± 25%。这在较高的高度是因为信号降低，在较低的高度是因为大气的穿透性降低。在体积混合比（VMR）方面，单个剖面精度从17 km处的4pptv提高到27 km处的8 pptv。可重复性是精度的另一个指标，对于SCIAMACHY检索，可重复性为2-3 pptv，与高度无关。平流层BrO数密度峰值一般位于对流层顶上方5 ± 2km处。在热带地区，平流层BrO VMR一般随高度增加而增加。观测到的平流层BrO全球分布通常与以前的气球测量结果一致，但与使用仅从观察到的长寿命溴代烷烃分解推断的Bry的模型的结果不太一致（即，甲基溴和哈龙）。我们发现与观测到的垂直和纬度分布的BrO的模型结果，其中包括一个8.4 ± 2 pptv的贡献平流层Bry，其中大部分是从VSL（非常短的寿命）溴碳的分解，除了16 pptv的贡献，从更长的寿命来源。这表明平流层Bry超过20 pptv。从气球测量BrO得到的Bry曲线也表明Bry超过20 pptv，但这些结果的不确定性和可变性不允许我们明确排除这种浓度。我们发现在热带对流层顶15公里处典型的BrO VMR为-4 pptv，这表明来自VSL溴代烷烃源的溴的很大一部分可能以无机分解产物的形式被携带穿过对流层顶。我们讨论了各种VSL溴碳物种，可能有助于平流层BrO浓度升高。
[1] Vertical profiles of stratospheric bromine monoxide (BrO) in the 15–30 km range are retrieved from SCIAMACHY limb scatter data over the globe. First validation comparisons with the balloon-borne SAOZ-BrO and LPMA/DOAS instruments indicate retrieval biases of � 20% or less. Propagated spectral fitting uncertainties lead to a precision approaching � 25% on a 2 km grid at 25 km. This worsens at higher altitudes because of reduced signal and at lower altitudes because of the reduced penetrability of the atmosphere. In terms of volume mixing ratio (VMR), the single profile precision increases from � 4 pptv at 17 km to � 8 pptv at 27 km. Repeatability, an alternative indicator of precision, is 2–3 pptv for SCIAMACHY retrievals and independent of altitude. The BrO stratospheric number density peak generally lies 5 ± 2 km above the tropopause. In the tropics, the stratospheric BrO VMR generally increases with increasing altitude. The observed stratospheric BrO global distribution is generally consistent with previous balloon measurements but does not agree well with results of a model that uses Bry inferred only from the observed breakdown of long-lived bromoalkanes (i.e., methyl bromide and halons). We find best agreement with the observed vertical and latitudinal distribution of BrO for model results that include an 8.4 ± 2 pptv contribution to stratospheric Bry, most of which is expected from the breakdown of VSL (very short lived) bromocarbons, in addition to the � 16 pptv contribution from longer-lived sources. This suggests that stratospheric Bry exceeds 20 pptv. Profiles of Bry profiles derived from the balloon measurements of BrO also suggest Bry is in excess of 20 pptv, but the uncertainty and variability of these results do not allow us to definitively rule out this concentration. We find typical BrO VMRs of � 4 pptv at 15 km in the tropical tropopause layer, suggesting that a significant portion of the bromine from VSL bromoalkane sources may be carried across the tropopause in the form of inorganic decomposition products. We discuss a variety of VSL bromocarbons species that may be contributing to the elevated concentrations of stratospheric BrO.