Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri
Iodine plays a vital role in oxidation chemistry over Antarctica, with past observations showing highly elevated levels of iodine oxide (IO) leading to severe depletion of boundary layer ozone in West Antarctica. Here, we present MAX-DOAS-based (multi-axis differential absorption spectroscopy) obser...
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ftcopernicus:oai:publications.copernicus.org:acp89935 2023-05-15T14:02:17+02:00 Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri Mahajan, Anoop S. Biswas, Mriganka S. Beirle, Steffen Wagner, Thomas Schönhardt, Anja Benavent, Nuria Saiz-Lopez, Alfonso 2021-08-09 application/pdf https://doi.org/10.5194/acp-21-11829-2021 https://acp.copernicus.org/articles/21/11829/2021/ eng eng doi:10.5194/acp-21-11829-2021 https://acp.copernicus.org/articles/21/11829/2021/ eISSN: 1680-7324 Text 2021 ftcopernicus https://doi.org/10.5194/acp-21-11829-2021 2021-08-16T16:22:29Z Iodine plays a vital role in oxidation chemistry over Antarctica, with past observations showing highly elevated levels of iodine oxide (IO) leading to severe depletion of boundary layer ozone in West Antarctica. Here, we present MAX-DOAS-based (multi-axis differential absorption spectroscopy) observations of IO over three summers (2015–2017) at the Indian Antarctic bases of Bharati and Maitri. IO was observed during all the campaigns with mixing ratios below 2 pptv (parts per trillion by volume) for the three summers, which are lower than the peak levels observed in West Antarctica. This suggests that sources in West Antarctica are different or stronger than sources of iodine compounds in East Antarctica, the nature of which is still uncertain. Vertical profiles estimated using a profile retrieval algorithm showed decreasing gradients with a peak in the lower boundary layer. The ground-based instrument retrieved vertical column densities (VCDs) were approximately a factor of 3 to 5 higher than the VCDs reported using satellite-based instruments, which is most likely related to the sensitivities of the measurement techniques. Air mass back-trajectory analysis failed to highlight a source region, with most of the air masses coming from coastal or continental regions. This study highlights the variation in iodine chemistry in different regions in Antarctica and the importance of a long-term dataset to validate models estimating the impacts of iodine chemistry. Text Antarc* Antarctic Antarctica East Antarctica West Antarctica Copernicus Publications: E-Journals Antarctic East Antarctica Indian Maitri ENVELOPE(11.733,11.733,-70.764,-70.764) West Antarctica Atmospheric Chemistry and Physics 21 15 11829 11842 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Iodine plays a vital role in oxidation chemistry over Antarctica, with past observations showing highly elevated levels of iodine oxide (IO) leading to severe depletion of boundary layer ozone in West Antarctica. Here, we present MAX-DOAS-based (multi-axis differential absorption spectroscopy) observations of IO over three summers (2015–2017) at the Indian Antarctic bases of Bharati and Maitri. IO was observed during all the campaigns with mixing ratios below 2 pptv (parts per trillion by volume) for the three summers, which are lower than the peak levels observed in West Antarctica. This suggests that sources in West Antarctica are different or stronger than sources of iodine compounds in East Antarctica, the nature of which is still uncertain. Vertical profiles estimated using a profile retrieval algorithm showed decreasing gradients with a peak in the lower boundary layer. The ground-based instrument retrieved vertical column densities (VCDs) were approximately a factor of 3 to 5 higher than the VCDs reported using satellite-based instruments, which is most likely related to the sensitivities of the measurement techniques. Air mass back-trajectory analysis failed to highlight a source region, with most of the air masses coming from coastal or continental regions. This study highlights the variation in iodine chemistry in different regions in Antarctica and the importance of a long-term dataset to validate models estimating the impacts of iodine chemistry. |
format |
Text |
author |
Mahajan, Anoop S. Biswas, Mriganka S. Beirle, Steffen Wagner, Thomas Schönhardt, Anja Benavent, Nuria Saiz-Lopez, Alfonso |
spellingShingle |
Mahajan, Anoop S. Biswas, Mriganka S. Beirle, Steffen Wagner, Thomas Schönhardt, Anja Benavent, Nuria Saiz-Lopez, Alfonso Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
author_facet |
Mahajan, Anoop S. Biswas, Mriganka S. Beirle, Steffen Wagner, Thomas Schönhardt, Anja Benavent, Nuria Saiz-Lopez, Alfonso |
author_sort |
Mahajan, Anoop S. |
title |
Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
title_short |
Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
title_full |
Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
title_fullStr |
Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
title_full_unstemmed |
Observations of iodine monoxide over three summers at the Indian Antarctic bases of Bharati and Maitri |
title_sort |
observations of iodine monoxide over three summers at the indian antarctic bases of bharati and maitri |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-11829-2021 https://acp.copernicus.org/articles/21/11829/2021/ |
long_lat |
ENVELOPE(11.733,11.733,-70.764,-70.764) |
geographic |
Antarctic East Antarctica Indian Maitri West Antarctica |
geographic_facet |
Antarctic East Antarctica Indian Maitri West Antarctica |
genre |
Antarc* Antarctic Antarctica East Antarctica West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica West Antarctica |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-21-11829-2021 https://acp.copernicus.org/articles/21/11829/2021/ |
op_doi |
https://doi.org/10.5194/acp-21-11829-2021 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
21 |
container_issue |
15 |
container_start_page |
11829 |
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11842 |
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1766272456434122752 |