Modelling the impacts of iodine chemistry on the northern Indian Ocean marine boundary layer
| Autor: | Qinyi Li, Anoop S. Mahajan, Alfonso Saiz-Lopez, Alba Badia, Kirpa Ram, Swaleha Inamdar |
|---|---|
| Přispěvatelé: | Ministry of Earth Sciences (India), European Commission |
| Rok vydání: | 2021 |
| Předmět: |
Atmospheric Science
Ozone 010504 meteorology & atmospheric sciences Chemistry Physics QC1-999 Iodine oxide 010501 environmental sciences Seasonality medicine.disease 01 natural sciences Atmosphere chemistry.chemical_compound Nitrate 13. Climate action Weather Research and Forecasting Model Environmental chemistry medicine 14. Life underwater Deposition (chemistry) Chemical composition QD1-999 0105 earth and related environmental sciences |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Atmospheric Chemistry and Physics, Vol 21, Pp 8437-8454 (2021) |
| ISSN: | 1680-7324 |
| Popis: | 18 pags., 10 figs., 2 tabs. Recent observations have shown the ubiquitous presence of iodine oxide (IO) in the Indian Ocean marine boundary layer (MBL). In this study, we use the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem version 3.7.1), including halogen (Br, Cl, and I) sources and chemistry, to quantify the impacts of the observed levels of iodine on the chemical composition of the MBL. The model results show that emissions of inorganic iodine species resulting from the deposition of ozone (span classCombining double low line"inline-formula"O3/span) on the sea surface are needed to reproduce the observed levels of IO, although the current parameterizations overestimate the atmospheric concentrations. After reducing the inorganic emissions by 40 %, a reasonable match with cruise-based observations is found, with the model predicting values between 0.1 and 1.2 span classCombining double low line"inline-formula"pptv/span across the model domain MBL. A strong seasonal variation is also observed, with lower iodine concentrations predicted during the monsoon period, when clean oceanic air advects towards the Indian subcontinent, and higher iodine concentrations predicted during the winter period, when polluted air from the Indian subcontinent increases the ozone concentrations in the remote MBL. The results show that significant changes are caused by the inclusion of iodine chemistry, with iodine-catalysed reactions leading to regional changes of up to 25 % in span classCombining double low line"inline-formula"O3/span, 50 % in nitrogen oxides (NO and span classCombining double low line"inline-formula"NO2/span), 15 % in hydroxyl radicals (OH), 25 % in hydroperoxyl radicals (span classCombining double low line"inline-formula"HO2/span), and up to a 50 % change in the nitrate radical (span classCombining double low line"inline-formula"NO3/span), with lower mean values across the domain. Most of the large relative changes are observed in the open-ocean MBL, although iodine chemistry also affects the chemical composition in the coastal environment and over the Indian subcontinent. These results show the importance of including iodine chemistry in modelling the atmosphere in this region./ The IITM is funded by the Ministry of Earth Sciences (MOES), government of India. This study has been funded by the European Research Council Executive Agency under the European Union’s Horizon 2020 research and innovation programme (project “ERC-2016-COG 726349 CLIMAHAL”). |
| Databáze: | OpenAIRE |
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