Retrievals of heavy ozone with MIPAS
Retrievals of heavy ozone with MIPAS
复制标题
用 MIPAS 反演重臭氧
DOI：
10.5194/amt-9-6069-2016
复制
发表时间：
2016
影响因子：
3.8
通讯作者：
T. Clarmann
中科院分区：
文献类型：
--
作者：
B. Jonkheid;T. Röckmann;N. Glatthor;C. Janssen;G. Stiller;T. Clarmann
摘要。提出了一种利用迈克尔逊被动大气探测干涉仪（MIPAS）反演平流层O3中18o取代同位素的方法。利用光滑正则化约束，反演了O3主同位素体、对称同位素体和非对称同位素体的体积混合比曲线。对于重同位素的检索，在MIPAS A波段（685-970 cm−1）和AB波段（1020-1170 cm−1）使用了两个微窗口。由于提取是作为对先前提取的先验剖面的扰动进行的，因此单个同位素体剖面的垂直分辨率非常相似，这在计算两种同位素体之间的比值时非常重要。利用2003年7月1日MIPAS记录的1044条垂直剖面对该方法的性能进行了评价。平均值用纬度带分开，并附有对其不确定度的估计。不对称同位素体的平均富集度为~ 8 %，垂直剖面在33 km处增加，在较高海拔处减少。这种随海拔的下降是一个不依赖于检索设置的可靠结果，并且在以前发表的数据集中没有明确报道。对称同位素体富集程度相对较低，平均值约为3 %，分布范围较大。在单个检索中，富集的不确定度主要由测量噪声（2-4 %）决定，可以通过多次检索平均来降低；与检索相关的系统不确定度通常很小，约为0.5 %，但由于关键光谱参数的不确定度未知，这可能被低估了。南半球的检索结果变化最大。
Abstract. A method for retrieval of 18O-substituted isotopomers of O3 in the stratosphere with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is presented. Using a smoothing regularisation constraint, volume mixing ratio profiles are retrieved for the main isotopologue and the symmetric and asymmetric isotopomers of singly substituted O3. For the retrieval of the heavy isotopologues, two microwindows in the MIPAS A band (685–970 cm−1) and six in the AB band (1020–1170 cm−1) are used. As the retrievals are performed as perturbations on the previously retrieved a priori profiles, the vertical resolution of the individual isotopomer profiles is very similar, which is important when calculating the ratio between two isotopomers. The performance of the method is evaluated using 1044 vertical profiles recorded with MIPAS on 1 July 2003. The mean values are separated by latitude bands, along with estimates of their uncertainties. The asymmetric isotopomer shows a mean enrichment of ∼ 8 %, with a vertical profile that increases up to 33 km and decreases at higher altitudes. This decrease with altitude is a robust result that does not depend on retrieval settings, and it has not been reported clearly in previously published datasets. The symmetric isotopomer is considerably less enriched, with mean values around 3 % and with a large spread. In individual retrievals the uncertainty of the enrichment is dominated by the measurement noise (2–4 %), which can be reduced by averaging multiple retrievals; systematic uncertainties linked to the retrieval are generally small at ∼ 0.5 %, but this is likely underestimated because the uncertainties in key spectroscopic parameters are unknown. The variabilities in the retrieval results are largest for the Southern Hemisphere.