The outflow of Asian biomass burning carbonaceous aerosol into the upper troposphere and lower stratosphere in spring: radiative effects seen in a global model
<p>Biomass burning (BB) over Asia is a strong source of carbonaceous aerosols during spring. From ECHAM6–HAMMOZ model simulations and satellite observations, we show that there is an outflow of Asian BB carbonaceous aerosols into the upper troposphere and lower stratosphere (UTLS) (black carbo...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/14371/2021/acp-21-14371-2021.pdf |
| Summary: | <p>Biomass burning (BB) over Asia is a strong source of carbonaceous aerosols during spring. From ECHAM6–HAMMOZ model simulations and satellite
observations, we show that there is an outflow of Asian BB carbonaceous
aerosols into the upper troposphere and lower stratosphere (UTLS) (black carbon: 0.1 to 6 ng m<span class="inline-formula"><sup>−3</sup></span> and organic carbon: 0.2 to 10 ng m<span class="inline-formula"><sup>−3</sup></span>)
during the spring season. The model simulations show that the greatest
transport of BB carbonaceous aerosols into the UTLS occurs from the
Indochina and East Asia region by deep convection over the Malay Peninsula and Indonesia. The increase in BB carbonaceous aerosols enhances atmospheric
heating by 0.001 to 0.02 K d<span class="inline-formula"><sup>−1</sup></span> in the UTLS. The aerosol-induced heating
and circulation changes increase the water vapor mixing ratios in the upper troposphere (by 20–80 ppmv) and in the lowermost stratosphere (by 0.02–0.3 ppmv) over the tropics. Once in the lower stratosphere, water vapor is
further transported to the South Pole by the lowermost branch of the
Brewer–Dobson circulation. These aerosols enhance the in-atmosphere radiative forcing (<span class="inline-formula">0.68±0.25</span> to <span class="inline-formula">5.30±0.37</span> W m<span class="inline-formula"><sup>−2</sup></span>), exacerbating atmospheric warming, but produce a cooling effect on climate (top of the
atmosphere – TOA: <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">2.38</mn><mo>±</mo><mn mathvariant="normal">0.12</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="64pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="caeaf8af2ce072dc5c345052a2eb35eb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-14371-2021-ie00001.svg" width="64pt" height="10pt" src="acp-21-14371-2021-ie00001.png"/></svg:svg></span></span> to <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">7.08</mn><mo>±</mo><mn mathvariant="normal">0.72</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="64pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="e3f23f81ec242a1b4557ebdba74004dd"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-14371-2021-ie00002.svg" width="64pt" height="10pt" src="acp-21-14371-2021-ie00002.png"/></svg:svg></span></span> W m<span class="inline-formula"><sup>−2</sup></span>). The model simulations also show that Asian carbonaceous aerosols are
transported to the Arctic in the troposphere. The maximum enhancement in
aerosol extinction is seen at 400 hPa (by 0.0093 km<span class="inline-formula"><sup>−1</sup></span>) and associated
heating rates at 300 hPa (by 0.032 K d<span class="inline-formula"><sup>−1</sup></span>) in the Arctic.</p> |
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| ISSN: | 1680-7316 1680-7324 |