Regime-based analysis of aerosol-cloud interactions
Previous global satellite studies into the indirect aerosol effect have relied on determining the sensitivity of derived Cloud Droplet Number Concentration (Nd) to co-located Aerosol Optical Depth (AOD). These studies generally find a positive Nd sensitivity to AOD changes over ocean, but some find...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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American Geophysical Union
2012
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| _version_ | 1797092713461448704 |
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| author | Gryspeerdt, E Stier, P |
| author_facet | Gryspeerdt, E Stier, P |
| author_sort | Gryspeerdt, E |
| collection | OXFORD |
| description | Previous global satellite studies into the indirect aerosol effect have relied on determining the sensitivity of derived Cloud Droplet Number Concentration (Nd) to co-located Aerosol Optical Depth (AOD). These studies generally find a positive Nd sensitivity to AOD changes over ocean, but some find a negative sensitivity over land, in contrast to that predicted by models and theory. Here we investigate the Nd sensitivity to AOD in different cloud regimes, determined using a k-means clustering process on retrieved cloud properties. We find the strongest positive Nd sensitivity in the stratiform regimes over both land and ocean, providing the majority of the total sensitivity. The negative sensitivity previously observed over land is generated by the low cloud fraction regimes, suggesting that it is due to the difficulty of retrieving Nd at low cloud fractions. When considering a mean sensitivity, weighted by liquid cloud fraction to account for sampling biases, we find an increased sensitivity over land, in some regions becoming positive. This highlights the importance of regime based analysis when studying aerosol indirect effects. |
| first_indexed | 2024-03-07T03:49:56Z |
| format | Journal article |
| id | oxford-uuid:c0e0a56f-bbf8-4370-a758-f09f7db8c8d4 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:49:56Z |
| publishDate | 2012 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:c0e0a56f-bbf8-4370-a758-f09f7db8c8d42022-03-27T05:57:33ZRegime-based analysis of aerosol-cloud interactionsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c0e0a56f-bbf8-4370-a758-f09f7db8c8d4EnglishSymplectic Elements at OxfordAmerican Geophysical Union2012Gryspeerdt, EStier, PPrevious global satellite studies into the indirect aerosol effect have relied on determining the sensitivity of derived Cloud Droplet Number Concentration (Nd) to co-located Aerosol Optical Depth (AOD). These studies generally find a positive Nd sensitivity to AOD changes over ocean, but some find a negative sensitivity over land, in contrast to that predicted by models and theory. Here we investigate the Nd sensitivity to AOD in different cloud regimes, determined using a k-means clustering process on retrieved cloud properties. We find the strongest positive Nd sensitivity in the stratiform regimes over both land and ocean, providing the majority of the total sensitivity. The negative sensitivity previously observed over land is generated by the low cloud fraction regimes, suggesting that it is due to the difficulty of retrieving Nd at low cloud fractions. When considering a mean sensitivity, weighted by liquid cloud fraction to account for sampling biases, we find an increased sensitivity over land, in some regions becoming positive. This highlights the importance of regime based analysis when studying aerosol indirect effects. |
| spellingShingle | Gryspeerdt, E Stier, P Regime-based analysis of aerosol-cloud interactions |
| title | Regime-based analysis of aerosol-cloud interactions |
| title_full | Regime-based analysis of aerosol-cloud interactions |
| title_fullStr | Regime-based analysis of aerosol-cloud interactions |
| title_full_unstemmed | Regime-based analysis of aerosol-cloud interactions |
| title_short | Regime-based analysis of aerosol-cloud interactions |
| title_sort | regime based analysis of aerosol cloud interactions |
| work_keys_str_mv | AT gryspeerdte regimebasedanalysisofaerosolcloudinteractions AT stierp regimebasedanalysisofaerosolcloudinteractions |