Method to retrieve cloud condensation nuclei number concentrations using lidar measurements
<p>Determination of cloud condensation nuclei (CCN) number concentrations at cloud base is important to constrain aerosol–cloud interactions. A new method to retrieve CCN number concentrations using backscatter and extinction profiles from multiwavelength Raman lidars is proposed. The method i...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-07-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/12/3825/2019/amt-12-3825-2019.pdf |
| _version_ | 1819015764920762368 |
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| author | W. Tan G. Zhao Y. Yu C. Li J. Li L. Kang T. Zhu C. Zhao |
| author_facet | W. Tan G. Zhao Y. Yu C. Li J. Li L. Kang T. Zhu C. Zhao |
| author_sort | W. Tan |
| collection | DOAJ |
| description | <p>Determination of cloud condensation nuclei (CCN) number
concentrations at cloud base is important to constrain aerosol–cloud
interactions. A new method to retrieve CCN number concentrations using
backscatter and extinction profiles from multiwavelength Raman lidars is
proposed. The method implements hygroscopic enhancements of backscatter and
extinction with relative humidity to derive dry backscatter and extinction
and humidogram parameters. Humidogram parameters, Ångström
exponents, and lidar extinction-to-backscatter ratios are then linked to the
ratio of CCN number concentration to dry backscatter and extinction
coefficient (<span class="inline-formula">AR<sub><i>ξ</i></sub></span>). This linkage is established based on
the datasets simulated by Mie theory and <span class="inline-formula"><i>κ</i></span>-Köhler theory with in-situ-measured particle size distributions and chemical compositions. CCN
number concentration can thus be calculated with <span class="inline-formula">AR<sub><i>ξ</i></sub></span> and
dry backscatter and extinction. An independent theoretical simulated dataset
is used to validate this new method and results show that the retrieved CCN
number concentrations at supersaturations of 0.07 %, 0.10 %, and
0.20 % are in good agreement with theoretical calculated values.
Sensitivity tests indicate that retrieval error in CCN arises mostly from
uncertainties in extinction coefficients and RH profiles. The proposed
method improves CCN retrieval from lidar measurements and has great
potential in deriving scarce long-term CCN data at cloud base, which benefits
aerosol–cloud interaction studies.</p> |
| first_indexed | 2024-12-21T02:36:56Z |
| format | Article |
| id | doaj.art-2b783e74d73147cc885f7c20b46300bf |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-21T02:36:56Z |
| publishDate | 2019-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-2b783e74d73147cc885f7c20b46300bf2022-12-21T19:18:46ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482019-07-01123825383910.5194/amt-12-3825-2019Method to retrieve cloud condensation nuclei number concentrations using lidar measurementsW. Tan0G. Zhao1Y. Yu2C. Li3J. Li4L. Kang5T. Zhu6C. Zhao7Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, ChinaDepartment of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, ChinaDepartment of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, ChinaDepartment of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, ChinaState Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science & Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science & Engineering, Peking University, Beijing 100871, ChinaDepartment of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China<p>Determination of cloud condensation nuclei (CCN) number concentrations at cloud base is important to constrain aerosol–cloud interactions. A new method to retrieve CCN number concentrations using backscatter and extinction profiles from multiwavelength Raman lidars is proposed. The method implements hygroscopic enhancements of backscatter and extinction with relative humidity to derive dry backscatter and extinction and humidogram parameters. Humidogram parameters, Ångström exponents, and lidar extinction-to-backscatter ratios are then linked to the ratio of CCN number concentration to dry backscatter and extinction coefficient (<span class="inline-formula">AR<sub><i>ξ</i></sub></span>). This linkage is established based on the datasets simulated by Mie theory and <span class="inline-formula"><i>κ</i></span>-Köhler theory with in-situ-measured particle size distributions and chemical compositions. CCN number concentration can thus be calculated with <span class="inline-formula">AR<sub><i>ξ</i></sub></span> and dry backscatter and extinction. An independent theoretical simulated dataset is used to validate this new method and results show that the retrieved CCN number concentrations at supersaturations of 0.07 %, 0.10 %, and 0.20 % are in good agreement with theoretical calculated values. Sensitivity tests indicate that retrieval error in CCN arises mostly from uncertainties in extinction coefficients and RH profiles. The proposed method improves CCN retrieval from lidar measurements and has great potential in deriving scarce long-term CCN data at cloud base, which benefits aerosol–cloud interaction studies.</p>https://www.atmos-meas-tech.net/12/3825/2019/amt-12-3825-2019.pdf |
| spellingShingle | W. Tan G. Zhao Y. Yu C. Li J. Li L. Kang T. Zhu C. Zhao Method to retrieve cloud condensation nuclei number concentrations using lidar measurements Atmospheric Measurement Techniques |
| title | Method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| title_full | Method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| title_fullStr | Method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| title_full_unstemmed | Method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| title_short | Method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| title_sort | method to retrieve cloud condensation nuclei number concentrations using lidar measurements |
| url | https://www.atmos-meas-tech.net/12/3825/2019/amt-12-3825-2019.pdf |
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