On the potential fingerprint of the Antarctica ozone hole in ice-core nitrate isotopes: a case study based on a South Pole ice core
<p>Column ozone variability has important implications for surface photochemistry and the climate. Ice-core nitrate isotopes are suspected to be influenced by column ozone variability and <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(N...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/13407/2022/acp-22-13407-2022.pdf |
| Summary: | <p>Column ozone variability has important implications for
surface photochemistry and the climate. Ice-core nitrate isotopes are suspected
to be influenced by column ozone variability and <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="53e1f98be2cdf70dbe180d95894fc6b5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00001.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00001.png"/></svg:svg></span></span>) has been sought to serve as a proxy of column
ozone variability. In this study, we examined the ability of ice-core
nitrate isotopes to reflect column ozone variability by measuring <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="0723f17b5be9fc41c36a5585631feb47"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00002.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00002.png"/></svg:svg></span></span>) and <span class="inline-formula">Δ<sup>17</sup></span>O(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="a6a4c5911a740e8377438efb607d4b86"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00003.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00003.png"/></svg:svg></span></span>) in a shallow
ice core drilled at the South Pole. The ice core covers the period 1944–2005, and during this period <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="7de8959157e6c258409d4c11688ca166"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00004.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00004.png"/></svg:svg></span></span>) showed
large annual variability ((59.2 <span class="inline-formula">±</span> 29.3) ‰ ), but
with no apparent response to the Antarctic ozone hole. Utilizing a snow
photochemical model, we estimated 6.9 ‰ additional
enrichments in <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="fa1148a5a7ab62133104fb46bf612014"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00005.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00005.png"/></svg:svg></span></span>) could be caused by the
development of the ozone hole. Nevertheless, this enrichment is small and
masked by the effects of the snow accumulation rate at the South Pole over the same period of the ozone hole. The <span class="inline-formula">Δ<sup>17</sup></span>O(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="a192f22c747584054322d55d69a940ca"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00006.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00006.png"/></svg:svg></span></span>) record
has displayed a decreasing trend by <span class="inline-formula">∼</span> 3.4 ‰
since 1976. This magnitude of change cannot be caused by enhanced
post-depositional processing related to the ozone hole. Instead, the <span class="inline-formula">Δ<sup>17</sup></span>O(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M16" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="06954914259a113e7faaa0d01a8ee756"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00007.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00007.png"/></svg:svg></span></span>) decrease was more likely due to the proposed
decreases in the O<span class="inline-formula"><sub>3</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M18" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="62d2c8208bbdf49afb8db19c9f7b6b50"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00008.svg" width="8pt" height="14pt" src="acp-22-13407-2022-ie00008.png"/></svg:svg></span></span> HO<span class="inline-formula"><sub><i>x</i></sub></span> ratio in the extratropical Southern
Hemisphere. Our results suggest ice-core <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="1eb1de86984802614b8a8a62ef6ea2cd"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00009.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00009.png"/></svg:svg></span></span>)
is more sensitive to snow accumulation rate than to column ozone, but at
sites with a relatively constant snow accumulation rate, information of column ozone variability embedded in <span class="inline-formula"><i>δ</i><sup>15</sup></span>N(NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="d4917cb251612ae03efebb0a66479930"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-13407-2022-ie00010.svg" width="9pt" height="16pt" src="acp-22-13407-2022-ie00010.png"/></svg:svg></span></span>) should be
retrievable.</p> |
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| ISSN: | 1680-7316 1680-7324 |