دورية أكاديمية
Technical note: Evaluation of profile retrievals of aerosols and trace gases for MAX-DOAS measurements under different aerosol scenarios based on radiative transfer simulations
| العنوان: | Technical note: Evaluation of profile retrievals of aerosols and trace gases for MAX-DOAS measurements under different aerosol scenarios based on radiative transfer simulations |
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| المؤلفون: | X. Tian, Y. Wang, S. Beirle, P. Xie, T. Wagner, J. Xu, A. Li, S. Dörner, B. Ren, X. Li |
| المصدر: | Atmospheric Chemistry and Physics, Vol 21, Pp 12867-12894 (2021) |
| بيانات النشر: | Copernicus Publications, 2021. |
| سنة النشر: | 2021 |
| المجموعة: | LCC:Physics LCC:Chemistry |
| مصطلحات موضوعية: | Physics, QC1-999, Chemistry, QD1-999 |
| الوصف: | Ground-based Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a state-of-the-art remote sensing technique for deriving vertical profiles of trace gases and aerosols. However, MAX-DOAS profile inversions under aerosol pollution scenarios are challenging because of the complex radiative transfer and limited information content of the measurements. In this study, the performances of two inversion algorithms were evaluated for various aerosol pollution scenarios based on synthetic slant column densities (SCDs) derived from radiative transfer simulations. Compared to previous studies, in our study, much larger ranges of aerosol optical depth (AOD) and NO2 vertical column densities (VCDs) are covered. One inversion algorithm is based on optimal estimation; the other uses a parameterized approach. In this analysis, three types of profile shapes for aerosols and NO2 were considered: exponential, Boltzmann, and Gaussian. First, the systematic deviations of the retrieved aerosol profiles from the input profiles were investigated. For most cases, the AODs of the retrieved profiles were found to be systematically lower than the input values, and the deviations increased with increasing AOD. In particular for the optimal estimation algorithm and for high AOD, these findings are consistent with the results in previous studies. The assumed single scattering albedo (SSA) and asymmetry parameter (AP) have a systematic influence on the aerosol retrieval. However, for most cases the influence of the assumed SSA and AP on the retrieval results are rather small (compared to other uncertainties). For the optimal estimation algorithm, the agreement with the input values can be improved by optimizing the covariance matrix of the a priori uncertainties. Second, the aerosol effects on the NO2 profile retrieval were tested. Here, especially for the optimal estimation algorithm, a systematic dependence on the NO2 VCD was found, with a strong relative overestimation of the retrieved results for low NO2 VCDs and an underestimation for high NO2 VCDs. In contrast, the dependence on the aerosol profiles was found to be rather low. Interestingly, the results for both investigated wavelengths (360 and 477 nm) were found to be rather similar, indicating that the differences in the radiative transfer between both wavelengths have no strong effect. In general, both inversion schemes can retrieve the near-surface values of aerosol extinction and trace gas concentrations well. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1680-7316 1680-7324 |
| العلاقة: | https://acp.copernicus.org/articles/21/12867/2021/acp-21-12867-2021.pdfTest; https://doaj.org/toc/1680-7316Test; https://doaj.org/toc/1680-7324Test |
| DOI: | 10.5194/acp-21-12867-2021 |
| الوصول الحر: | https://doaj.org/article/553a78d5d82e4de381366f3d5ee3428bTest |
| رقم الانضمام: | edsdoj.553a78d5d82e4de381366f3d5ee3428b |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 16807316 16807324 |
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| DOI: | 10.5194/acp-21-12867-2021 |