Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic
<p>The magnitude of solar radiative effects (cooling or warming) of black carbon (BC) particles embedded in the Arctic atmosphere and surface snow layer was explored on the basis of case studies. For this purpose, combined atmospheric and snow radiative transfer simulations were performed for...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/8139/2020/acp-20-8139-2020.pdf |
| _version_ | 1818597460682997760 |
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| author | T. Donth E. Jäkel A. Ehrlich B. Heinold J. Schacht A. Herber M. Zanatta M. Wendisch |
| author_facet | T. Donth E. Jäkel A. Ehrlich B. Heinold J. Schacht A. Herber M. Zanatta M. Wendisch |
| author_sort | T. Donth |
| collection | DOAJ |
| description | <p>The magnitude of solar radiative effects (cooling or warming) of black carbon (BC) particles embedded in the Arctic atmosphere and surface snow layer was explored on the basis of case studies. For this purpose, combined atmospheric and snow radiative transfer simulations were performed for cloudless and cloudy conditions on the basis of BC mass concentrations measured in pristine early summer and more polluted early spring conditions. The area of interest is the remote sea-ice-covered Arctic Ocean in the vicinity of Spitsbergen, northern Greenland, and northern Alaska typically not affected by local pollution. To account for the radiative interactions between the black-carbon-containing snow surface layer and the atmosphere, an atmospheric and snow radiative transfer model were coupled iteratively.
For pristine summer conditions (no atmospheric BC, minimum solar zenith angles of 55<span class="inline-formula"><sup>∘</sup></span>) and a representative BC particle mass concentration of 5 ng g<span class="inline-formula"><sup>−1</sup></span> in the surface snow layer, a positive daily mean solar radiative forcing of <span class="inline-formula">+</span>0.2 W m<span class="inline-formula"><sup>−2</sup></span> was calculated for the surface radiative budget. A higher load of atmospheric BC representing early springtime conditions results in a slightly negative mean radiative forcing at the surface of about <span class="inline-formula">−</span>0.05 W m<span class="inline-formula"><sup>−2</sup></span>, even when the low BC mass concentration measured in the pristine early summer conditions was embedded in the surface snow layer. The total net surface radiative forcing combining the effects of BC embedded in the atmosphere and in the snow layer strongly depends on the snow optical properties (snow specific surface area and snow density).
For the conditions over the Arctic Ocean analyzed in the simulations, it was found that the atmospheric heating rate by water vapor or clouds is 1 to 2 orders of magnitude larger than that by atmospheric BC. Similarly, the daily mean total heating rate (6 K d<span class="inline-formula"><sup>−1</sup></span>) within a snowpack due to absorption by the ice was more than 1 order of magnitude larger than that of atmospheric BC (0.2 K d<span class="inline-formula"><sup>−1</sup></span>).
Also, it was shown that the cooling by atmospheric BC of the near-surface air and the warming effect by BC embedded in snow are reduced in the presence of clouds.</p> |
| first_indexed | 2024-12-16T11:48:10Z |
| format | Article |
| id | doaj.art-c28d0fe4839040d98a93df031453b52b |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-16T11:48:10Z |
| publishDate | 2020-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-c28d0fe4839040d98a93df031453b52b2022-12-21T22:32:47ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-07-01208139815610.5194/acp-20-8139-2020Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the ArcticT. Donth0E. Jäkel1A. Ehrlich2B. Heinold3J. Schacht4A. Herber5M. Zanatta6M. Wendisch7Leipzig Institute for Meteorology (LIM), University of Leipzig, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), University of Leipzig, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), University of Leipzig, Leipzig, GermanyLeibniz Institute for Tropospheric Research, (TROPOS), Leipzig, GermanyLeibniz Institute for Tropospheric Research, (TROPOS), Leipzig, GermanyAlfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Bremerhaven, GermanyAlfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Bremerhaven, GermanyLeipzig Institute for Meteorology (LIM), University of Leipzig, Leipzig, Germany<p>The magnitude of solar radiative effects (cooling or warming) of black carbon (BC) particles embedded in the Arctic atmosphere and surface snow layer was explored on the basis of case studies. For this purpose, combined atmospheric and snow radiative transfer simulations were performed for cloudless and cloudy conditions on the basis of BC mass concentrations measured in pristine early summer and more polluted early spring conditions. The area of interest is the remote sea-ice-covered Arctic Ocean in the vicinity of Spitsbergen, northern Greenland, and northern Alaska typically not affected by local pollution. To account for the radiative interactions between the black-carbon-containing snow surface layer and the atmosphere, an atmospheric and snow radiative transfer model were coupled iteratively. For pristine summer conditions (no atmospheric BC, minimum solar zenith angles of 55<span class="inline-formula"><sup>∘</sup></span>) and a representative BC particle mass concentration of 5 ng g<span class="inline-formula"><sup>−1</sup></span> in the surface snow layer, a positive daily mean solar radiative forcing of <span class="inline-formula">+</span>0.2 W m<span class="inline-formula"><sup>−2</sup></span> was calculated for the surface radiative budget. A higher load of atmospheric BC representing early springtime conditions results in a slightly negative mean radiative forcing at the surface of about <span class="inline-formula">−</span>0.05 W m<span class="inline-formula"><sup>−2</sup></span>, even when the low BC mass concentration measured in the pristine early summer conditions was embedded in the surface snow layer. The total net surface radiative forcing combining the effects of BC embedded in the atmosphere and in the snow layer strongly depends on the snow optical properties (snow specific surface area and snow density). For the conditions over the Arctic Ocean analyzed in the simulations, it was found that the atmospheric heating rate by water vapor or clouds is 1 to 2 orders of magnitude larger than that by atmospheric BC. Similarly, the daily mean total heating rate (6 K d<span class="inline-formula"><sup>−1</sup></span>) within a snowpack due to absorption by the ice was more than 1 order of magnitude larger than that of atmospheric BC (0.2 K d<span class="inline-formula"><sup>−1</sup></span>). Also, it was shown that the cooling by atmospheric BC of the near-surface air and the warming effect by BC embedded in snow are reduced in the presence of clouds.</p>https://www.atmos-chem-phys.net/20/8139/2020/acp-20-8139-2020.pdf |
| spellingShingle | T. Donth E. Jäkel A. Ehrlich B. Heinold J. Schacht A. Herber M. Zanatta M. Wendisch Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic Atmospheric Chemistry and Physics |
| title | Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic |
| title_full | Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic |
| title_fullStr | Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic |
| title_full_unstemmed | Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic |
| title_short | Combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the Arctic |
| title_sort | combining atmospheric and snow radiative transfer models to assess the solar radiative effects of black carbon in the arctic |
| url | https://www.atmos-chem-phys.net/20/8139/2020/acp-20-8139-2020.pdf |
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