Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations
<p>Understanding the evolution of the ice phase within mixed-phase clouds (MPCs) is necessary to reduce uncertainties related to the cloud radiative feedback in climate projections and precipitation initiation. Both primary ice formation via ice-nucleating particles (INPs) and secondary ice pr...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/9767/2022/acp-22-9767-2022.pdf |
| _version_ | 1811221579731828736 |
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| author | J. Wieder N. Ihn C. Mignani C. Mignani M. Haarig J. Bühl P. Seifert R. Engelmann F. Ramelli Z. A. Kanji U. Lohmann J. Henneberger |
| author_facet | J. Wieder N. Ihn C. Mignani C. Mignani M. Haarig J. Bühl P. Seifert R. Engelmann F. Ramelli Z. A. Kanji U. Lohmann J. Henneberger |
| author_sort | J. Wieder |
| collection | DOAJ |
| description | <p>Understanding the evolution of the ice phase within mixed-phase clouds (MPCs) is necessary to reduce uncertainties related to the cloud radiative feedback in climate projections and precipitation initiation. Both primary ice formation via ice-nucleating particles (INPs) and secondary ice production (SIP) within MPCs are unconstrained, not least because of the lack of atmospheric observations. In the past decades, advanced remote sensing methods have emerged which provide high-resolution data of aerosol and cloud properties and could be key in understanding microphysical processes on a global scale. In this study, we retrieved INP concentrations and ice multiplication factors (IMFs) in wintertime orographic clouds using active remote sensing and in situ observations obtained during the RACLETS campaign in the Swiss Alps. INP concentrations in air masses dominated by Saharan dust and continental aerosol were retrieved from a polarization Raman lidar and validated with aerosol and INP in situ observations on a mountaintop. A calibration factor of <span class="inline-formula">0.0204</span> for the global INP parameterization by <span class="cit" id="xref_text.1"><a href="#bib1.bibx26">DeMott et al.</a> (<a href="#bib1.bibx26">2010</a>)</span> is derived by comparing in situ aerosol and INP measurements, improving the INP concentration retrieval for continental aerosols. Based on combined lidar and radar measurements, the ice crystal number concentration and ice water content were retrieved and validated with balloon-borne in situ observations, which agreed with the balloon-borne in situ observations within an order of magnitude. For seven cloud cases the ice multiplication factors (IMFs), defined as the quotient of the ice crystal number concentration to the INP concentration, were calculated. The median IMF was around 80, and SIP was active (defined as IMFs <span class="inline-formula">></span> 1) nearly 85 % of the time. SIP was found to be active at all observed temperatures (<span class="inline-formula">−30</span> to <span class="inline-formula">−5</span> <span class="inline-formula"><sup>∘</sup></span>C), with the highest IMFs between <span class="inline-formula">−20</span> and <span class="inline-formula">−5</span> <span class="inline-formula"><sup>∘</sup></span>C. The introduced methodology could be extended to larger datasets to better understand the impact of SIP not only over the Alps but also at other locations and for other cloud types.</p> |
| first_indexed | 2024-04-12T08:02:57Z |
| format | Article |
| id | doaj.art-1cef64ddabfb40db8006cfd3c8e74904 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-12T08:02:57Z |
| publishDate | 2022-08-01 |
| publisher | Copernicus Publications |
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| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-1cef64ddabfb40db8006cfd3c8e749042022-12-22T03:41:15ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-08-01229767979710.5194/acp-22-9767-2022Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observationsJ. Wieder0N. Ihn1C. Mignani2C. Mignani3M. Haarig4J. Bühl5P. Seifert6R. Engelmann7F. Ramelli8Z. A. Kanji9U. Lohmann10J. Henneberger11ETH Zurich, Institute for Atmospheric and Climate Science, Zurich, SwitzerlandETH Zurich, Institute for Atmospheric and Climate Science, Zurich, SwitzerlandDepartment of Environmental Sciences, University of Basel, Basel, Switzerlandnow at: Department of Atmospheric Science, Colorado State University, Fort Collins, USALeibniz Institute for Tropospheric Research, Leipzig, GermanyLeibniz Institute for Tropospheric Research, Leipzig, GermanyLeibniz Institute for Tropospheric Research, Leipzig, GermanyLeibniz Institute for Tropospheric Research, Leipzig, GermanyETH Zurich, Institute for Atmospheric and Climate Science, Zurich, SwitzerlandETH Zurich, Institute for Atmospheric and Climate Science, Zurich, SwitzerlandETH Zurich, Institute for Atmospheric and Climate Science, Zurich, SwitzerlandETH Zurich, Institute for Atmospheric and Climate Science, Zurich, Switzerland<p>Understanding the evolution of the ice phase within mixed-phase clouds (MPCs) is necessary to reduce uncertainties related to the cloud radiative feedback in climate projections and precipitation initiation. Both primary ice formation via ice-nucleating particles (INPs) and secondary ice production (SIP) within MPCs are unconstrained, not least because of the lack of atmospheric observations. In the past decades, advanced remote sensing methods have emerged which provide high-resolution data of aerosol and cloud properties and could be key in understanding microphysical processes on a global scale. In this study, we retrieved INP concentrations and ice multiplication factors (IMFs) in wintertime orographic clouds using active remote sensing and in situ observations obtained during the RACLETS campaign in the Swiss Alps. INP concentrations in air masses dominated by Saharan dust and continental aerosol were retrieved from a polarization Raman lidar and validated with aerosol and INP in situ observations on a mountaintop. A calibration factor of <span class="inline-formula">0.0204</span> for the global INP parameterization by <span class="cit" id="xref_text.1"><a href="#bib1.bibx26">DeMott et al.</a> (<a href="#bib1.bibx26">2010</a>)</span> is derived by comparing in situ aerosol and INP measurements, improving the INP concentration retrieval for continental aerosols. Based on combined lidar and radar measurements, the ice crystal number concentration and ice water content were retrieved and validated with balloon-borne in situ observations, which agreed with the balloon-borne in situ observations within an order of magnitude. For seven cloud cases the ice multiplication factors (IMFs), defined as the quotient of the ice crystal number concentration to the INP concentration, were calculated. The median IMF was around 80, and SIP was active (defined as IMFs <span class="inline-formula">></span> 1) nearly 85 % of the time. SIP was found to be active at all observed temperatures (<span class="inline-formula">−30</span> to <span class="inline-formula">−5</span> <span class="inline-formula"><sup>∘</sup></span>C), with the highest IMFs between <span class="inline-formula">−20</span> and <span class="inline-formula">−5</span> <span class="inline-formula"><sup>∘</sup></span>C. The introduced methodology could be extended to larger datasets to better understand the impact of SIP not only over the Alps but also at other locations and for other cloud types.</p>https://acp.copernicus.org/articles/22/9767/2022/acp-22-9767-2022.pdf |
| spellingShingle | J. Wieder N. Ihn C. Mignani C. Mignani M. Haarig J. Bühl P. Seifert R. Engelmann F. Ramelli Z. A. Kanji U. Lohmann J. Henneberger Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations Atmospheric Chemistry and Physics |
| title | Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| title_full | Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| title_fullStr | Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| title_full_unstemmed | Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| title_short | Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| title_sort | retrieving ice nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations |
| url | https://acp.copernicus.org/articles/22/9767/2022/acp-22-9767-2022.pdf |
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