Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing
<p>Multi-year ground-based remote-sensing datasets were acquired with the Leipzig Aerosol and Cloud Remote Observations System (LACROS) at three sites. A highly polluted central European site (Leipzig, Germany), a polluted and strongly dust-influenced eastern Mediterranean site (Limassol, Cypr...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-12-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/17969/2021/acp-21-17969-2021.pdf |
| _version_ | 1818851782646824960 |
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| author | M. Radenz J. Bühl P. Seifert H. Baars R. Engelmann B. Barja González R.-E. Mamouri R.-E. Mamouri F. Zamorano A. Ansmann |
| author_facet | M. Radenz J. Bühl P. Seifert H. Baars R. Engelmann B. Barja González R.-E. Mamouri R.-E. Mamouri F. Zamorano A. Ansmann |
| author_sort | M. Radenz |
| collection | DOAJ |
| description | <p>Multi-year ground-based remote-sensing datasets were acquired with the Leipzig
Aerosol and Cloud Remote Observations System (LACROS) at three sites. A highly
polluted central European site (Leipzig, Germany), a polluted and strongly
dust-influenced eastern Mediterranean site (Limassol, Cyprus), and a clean
marine site in the southern midlatitudes (Punta Arenas, Chile) are used to
contrast ice formation in shallow stratiform liquid clouds. These unique,
long-term datasets in key regions of aerosol–cloud interaction provide a
deeper insight into cloud microphysics. The influence of temperature, aerosol
load, boundary layer coupling, and gravity wave motion on ice formation is
investigated. With respect to previous studies of regional contrasts in the
properties of mixed-phase clouds, our study contributes the following new
aspects: (1) sampling aerosol optical parameters as a function of temperature,
the average backscatter coefficient at supercooled conditions is within a
factor of 3 at all three sites. (2) Ice formation was found to be more
frequent for cloud layers with cloud top temperatures above
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">15</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="35pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="1eed06dae4d27e0aee11ba45b1aafd8b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00001.svg" width="35pt" height="11pt" src="acp-21-17969-2021-ie00001.png"/></svg:svg></span></span> than indicated by prior lidar-only studies at all
sites. A virtual lidar detection threshold of ice water content (IWC) needs to be considered in
order to bring radar–lidar-based studies in agreement with lidar-only studies.
(3) At similar temperatures, cloud layers which are coupled to the
aerosol-laden boundary layer show more intense ice formation than decoupled
clouds. (4) Liquid layers formed by gravity waves were found to bias the
phase occurrence statistics below <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">15</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="35pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="9bab716971d5669dabbec02ea0a29aac"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00002.svg" width="35pt" height="11pt" src="acp-21-17969-2021-ie00002.png"/></svg:svg></span></span>. By applying a
novel gravity wave detection approach using vertical velocity observations
within the liquid-dominated cloud top, wave clouds can be classified and
excluded from the statistics. After considering boundary layer and
gravity wave influences, Punta Arenas shows lower fractions of ice-containing
clouds by <span class="inline-formula">0.1</span> to <span class="inline-formula">0.4</span> absolute difference at temperatures between <span class="inline-formula">−24</span> and
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">8</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="a7a84e29fb46470c77f66350d9689e76"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00003.svg" width="29pt" height="11pt" src="acp-21-17969-2021-ie00003.png"/></svg:svg></span></span>. These differences are potentially caused by the
contrast in the ice-nucleating particle (INP) reservoir between the different sites.</p> |
| first_indexed | 2024-12-19T07:10:30Z |
| format | Article |
| id | doaj.art-fccf703d147b42be90bc8bc3fc9db570 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-19T07:10:30Z |
| publishDate | 2021-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-fccf703d147b42be90bc8bc3fc9db5702022-12-21T20:31:13ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242021-12-0121179691799410.5194/acp-21-17969-2021Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensingM. Radenz0J. Bühl1P. Seifert2H. Baars3R. Engelmann4B. Barja González5R.-E. Mamouri6R.-E. Mamouri7F. Zamorano8A. Ansmann9Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, GermanyLeibniz Institute for Tropospheric Research (TROPOS), Leipzig, GermanyLeibniz Institute for Tropospheric Research (TROPOS), Leipzig, GermanyLeibniz Institute for Tropospheric Research (TROPOS), Leipzig, GermanyLeibniz Institute for Tropospheric Research (TROPOS), Leipzig, GermanyAtmospheric Research Laboratory, University of Magallanes, Punta Arenas, ChileDepartment of Civil Engineering and Geomatics, Cyprus University of Technology of Technology, Limassol, CyprusERATOSTHENES Centre of Excellence, Limassol, CyprusAtmospheric Research Laboratory, University of Magallanes, Punta Arenas, ChileLeibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany<p>Multi-year ground-based remote-sensing datasets were acquired with the Leipzig Aerosol and Cloud Remote Observations System (LACROS) at three sites. A highly polluted central European site (Leipzig, Germany), a polluted and strongly dust-influenced eastern Mediterranean site (Limassol, Cyprus), and a clean marine site in the southern midlatitudes (Punta Arenas, Chile) are used to contrast ice formation in shallow stratiform liquid clouds. These unique, long-term datasets in key regions of aerosol–cloud interaction provide a deeper insight into cloud microphysics. The influence of temperature, aerosol load, boundary layer coupling, and gravity wave motion on ice formation is investigated. With respect to previous studies of regional contrasts in the properties of mixed-phase clouds, our study contributes the following new aspects: (1) sampling aerosol optical parameters as a function of temperature, the average backscatter coefficient at supercooled conditions is within a factor of 3 at all three sites. (2) Ice formation was found to be more frequent for cloud layers with cloud top temperatures above <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">15</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="35pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="1eed06dae4d27e0aee11ba45b1aafd8b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00001.svg" width="35pt" height="11pt" src="acp-21-17969-2021-ie00001.png"/></svg:svg></span></span> than indicated by prior lidar-only studies at all sites. A virtual lidar detection threshold of ice water content (IWC) needs to be considered in order to bring radar–lidar-based studies in agreement with lidar-only studies. (3) At similar temperatures, cloud layers which are coupled to the aerosol-laden boundary layer show more intense ice formation than decoupled clouds. (4) Liquid layers formed by gravity waves were found to bias the phase occurrence statistics below <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">15</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="35pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="9bab716971d5669dabbec02ea0a29aac"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00002.svg" width="35pt" height="11pt" src="acp-21-17969-2021-ie00002.png"/></svg:svg></span></span>. By applying a novel gravity wave detection approach using vertical velocity observations within the liquid-dominated cloud top, wave clouds can be classified and excluded from the statistics. After considering boundary layer and gravity wave influences, Punta Arenas shows lower fractions of ice-containing clouds by <span class="inline-formula">0.1</span> to <span class="inline-formula">0.4</span> absolute difference at temperatures between <span class="inline-formula">−24</span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">8</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="a7a84e29fb46470c77f66350d9689e76"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-17969-2021-ie00003.svg" width="29pt" height="11pt" src="acp-21-17969-2021-ie00003.png"/></svg:svg></span></span>. These differences are potentially caused by the contrast in the ice-nucleating particle (INP) reservoir between the different sites.</p>https://acp.copernicus.org/articles/21/17969/2021/acp-21-17969-2021.pdf |
| spellingShingle | M. Radenz J. Bühl P. Seifert H. Baars R. Engelmann B. Barja González R.-E. Mamouri R.-E. Mamouri F. Zamorano A. Ansmann Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing Atmospheric Chemistry and Physics |
| title | Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing |
| title_full | Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing |
| title_fullStr | Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing |
| title_full_unstemmed | Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing |
| title_short | Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing |
| title_sort | hemispheric contrasts in ice formation in stratiform mixed phase clouds disentangling the role of aerosol and dynamics with ground based remote sensing |
| url | https://acp.copernicus.org/articles/21/17969/2021/acp-21-17969-2021.pdf |
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