Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0
<p>Sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn math...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-03-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/15/2013/2022/gmd-15-2013-2022.pdf |
| _version_ | 1819320408344625152 |
|---|---|
| author | Y. Sasaki H. Kobayashi A. Oka |
| author_facet | Y. Sasaki H. Kobayashi A. Oka |
| author_sort | Y. Sasaki |
| collection | DOAJ |
| description | <p>Sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="b118a40effcf5fa5b508e16481bf10eb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00003.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00003.png"/></svg:svg></span></span> ratios provide clues to estimate
the strength of past ocean circulation. For its estimation, understanding
the processes controlling the distributions of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in
the ocean is important. However, simulations of dissolved and particulate
<span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the modern ocean, recently obtained from the
GEOTRACES project, remain challenging. Here we report a model simulation of
<span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the global ocean with COCO ver4.0. Starting
from the basic water-column reversible scavenging model, we also introduced
the bottom scavenging and the dependence of scavenging efficiency on
particle concentration. As demonstrated in a previous study, the
incorporation of bottom scavenging improves the simulated distribution of
dissolved <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the deep ocean, which has been
overestimated in models not considering the bottom scavenging. We further
demonstrate that introducing the dependence of scavenging efficiency on
particle concentration results in a high concentration of dissolved
<span class="inline-formula"><sup>230</sup></span>Th in the Southern Ocean as observed in the GEOTRACES data. Our best
simulation can well reproduce not only the oceanic distribution of
<span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th but also the sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M18" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="b8319888bc40921273c73b7cd1e5cbe6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00004.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00004.png"/></svg:svg></span></span>
ratios. Sensitivity analysis reveals that oceanic advection of <span class="inline-formula"><sup>231</sup></span>Pa
primarily determines sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M20" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="c4b0423d41c5d81802398fc02d125a89"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00005.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00005.png"/></svg:svg></span></span> ratios. On the other
hand, <span class="inline-formula"><sup>230</sup></span>Th advection and bottom scavenging have an opposite effect to
<span class="inline-formula"><sup>231</sup></span>Pa advection on the sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="19b56b7d101a64fabbf8004913101743"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00006.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00006.png"/></svg:svg></span></span> ratios,
reducing their latitudinal contrast. Our best simulation shows the realistic
residence times of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th, but simulation without bottom
scavenging and dependence of scavenging efficiency on particle concentration
significantly overestimates the residence times for both <span class="inline-formula"><sup>231</sup></span>Pa and
<span class="inline-formula"><sup>230</sup></span>Th in spite of similar distribution of sedimentary
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="22b8c13296a4bf8bfe5fbb6a67ed48a5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00007.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00007.png"/></svg:svg></span></span> ratios to our best simulation.</p> |
| first_indexed | 2024-12-24T11:19:06Z |
| format | Article |
| id | doaj.art-933793b5ceee41668f67b0672df777b2 |
| institution | Directory Open Access Journal |
| issn | 1991-959X 1991-9603 |
| language | English |
| last_indexed | 2024-12-24T11:19:06Z |
| publishDate | 2022-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj.art-933793b5ceee41668f67b0672df777b22022-12-21T16:58:18ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032022-03-01152013203310.5194/gmd-15-2013-2022Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0Y. SasakiH. KobayashiA. Oka<p>Sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="b118a40effcf5fa5b508e16481bf10eb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00003.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00003.png"/></svg:svg></span></span> ratios provide clues to estimate the strength of past ocean circulation. For its estimation, understanding the processes controlling the distributions of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the ocean is important. However, simulations of dissolved and particulate <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the modern ocean, recently obtained from the GEOTRACES project, remain challenging. Here we report a model simulation of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the global ocean with COCO ver4.0. Starting from the basic water-column reversible scavenging model, we also introduced the bottom scavenging and the dependence of scavenging efficiency on particle concentration. As demonstrated in a previous study, the incorporation of bottom scavenging improves the simulated distribution of dissolved <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in the deep ocean, which has been overestimated in models not considering the bottom scavenging. We further demonstrate that introducing the dependence of scavenging efficiency on particle concentration results in a high concentration of dissolved <span class="inline-formula"><sup>230</sup></span>Th in the Southern Ocean as observed in the GEOTRACES data. Our best simulation can well reproduce not only the oceanic distribution of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th but also the sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M18" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="b8319888bc40921273c73b7cd1e5cbe6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00004.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00004.png"/></svg:svg></span></span> ratios. Sensitivity analysis reveals that oceanic advection of <span class="inline-formula"><sup>231</sup></span>Pa primarily determines sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M20" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="c4b0423d41c5d81802398fc02d125a89"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00005.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00005.png"/></svg:svg></span></span> ratios. On the other hand, <span class="inline-formula"><sup>230</sup></span>Th advection and bottom scavenging have an opposite effect to <span class="inline-formula"><sup>231</sup></span>Pa advection on the sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="19b56b7d101a64fabbf8004913101743"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00006.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00006.png"/></svg:svg></span></span> ratios, reducing their latitudinal contrast. Our best simulation shows the realistic residence times of <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th, but simulation without bottom scavenging and dependence of scavenging efficiency on particle concentration significantly overestimates the residence times for both <span class="inline-formula"><sup>231</sup></span>Pa and <span class="inline-formula"><sup>230</sup></span>Th in spite of similar distribution of sedimentary <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">231</mn></msup><mi mathvariant="normal">Pa</mi><msup><mo>/</mo><mn mathvariant="normal">230</mn></msup><mi mathvariant="normal">Th</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="22b8c13296a4bf8bfe5fbb6a67ed48a5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-15-2013-2022-ie00007.svg" width="62pt" height="15pt" src="gmd-15-2013-2022-ie00007.png"/></svg:svg></span></span> ratios to our best simulation.</p>https://gmd.copernicus.org/articles/15/2013/2022/gmd-15-2013-2022.pdf |
| spellingShingle | Y. Sasaki H. Kobayashi A. Oka Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 Geoscientific Model Development |
| title | Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 |
| title_full | Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 |
| title_fullStr | Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 |
| title_full_unstemmed | Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 |
| title_short | Global simulation of dissolved <sup>231</sup>Pa and <sup>230</sup>Th in the ocean and the sedimentary <sup>231</sup>Pa∕<sup>230</sup>Th ratios with the ocean general circulation model COCO ver4.0 |
| title_sort | global simulation of dissolved sup 231 sup pa and sup 230 sup th in the ocean and the sedimentary sup 231 sup pa sup 230 sup th ratios with the ocean general circulation model coco ver4 0 |
| url | https://gmd.copernicus.org/articles/15/2013/2022/gmd-15-2013-2022.pdf |
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