Model-Specific Radiative Kernels for Calculating Cloud and Noncloud Climate Feedbacks.
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| Title: | Model-Specific Radiative Kernels for Calculating Cloud and Noncloud Climate Feedbacks. |
|---|---|
| Authors: | Sanderson, Benjamin M., Shell, Karen M. |
| Source: | Journal of Climate. Nov2012, Vol. 25 Issue 21, p7607-7624. 18p. 1 Color Photograph, 2 Charts, 5 Graphs, 2 Maps. |
| Subjects: | Radiative forcing, Computer simulation of climate change, General circulation model, Kernel (Mathematics), Histograms, Stratocumulus clouds |
| Abstract: | Radiative kernels have become a common tool for evaluating and comparing radiative feedbacks to climate change in different general circulation models. However, kernel feedback calculations are inaccurate for simulations where the atmosphere is significantly perturbed from its base state, such as for very large forcing or perturbed physics simulations. In addition, past analyses have not produced kernels relating to prognostic cloud variables because of strong nonlinearities in their relationship to radiative forcing. A new methodology is presented that allows for fast statistical optimizing of existing kernels such that accuracy is increased for significantly altered climatologies. International Satellite Cloud Climatology Project (ISCCP) simulator output is used to relate changes in cloud-type histograms to radiative fluxes. With minimal additional computation, an individual set of kernels is created for each climate experiment such that climate feedbacks can be reliably estimated even in significantly perturbed climates. This methodology is applied to successive generations of the Community Atmosphere Model (CAM). Increased climate sensitivity in CAM5 is shown to be due to reduced negative stratus and stratocumulus feedbacks in the tropics and midlatitudes, strong positive stratus feedbacks in the southern oceans, and a strengthened positive longwave cirrus feedback. Results also suggest that CAM5 exhibits a stronger surface albedo feedback than its predecessors, a feature not apparent when using a single kernel. Optimized kernels for CAM5 suggest weaker global-mean shortwave cloud feedback than one would infer from using the original kernels and an adjusted cloud radiative forcing methodology. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Climate is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 83356228 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Model-Specific Radiative Kernels for Calculating Cloud and Noncloud Climate Feedbacks. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Sanderson%2C+Benjamin+M%2E%22">Sanderson, Benjamin M.</searchLink><br /><searchLink fieldCode="AR" term="%22Shell%2C+Karen+M%2E%22">Shell, Karen M.</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Climate%22">Journal of Climate</searchLink>. Nov2012, Vol. 25 Issue 21, p7607-7624. 18p. 1 Color Photograph, 2 Charts, 5 Graphs, 2 Maps. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Radiative+forcing%22">Radiative forcing</searchLink><br /><searchLink fieldCode="DE" term="%22Computer+simulation+of+climate+change%22">Computer simulation of climate change</searchLink><br /><searchLink fieldCode="DE" term="%22General+circulation+model%22">General circulation model</searchLink><br /><searchLink fieldCode="DE" term="%22Kernel+%28Mathematics%29%22">Kernel (Mathematics)</searchLink><br /><searchLink fieldCode="DE" term="%22Histograms%22">Histograms</searchLink><br /><searchLink fieldCode="DE" term="%22Stratocumulus+clouds%22">Stratocumulus clouds</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Radiative kernels have become a common tool for evaluating and comparing radiative feedbacks to climate change in different general circulation models. However, kernel feedback calculations are inaccurate for simulations where the atmosphere is significantly perturbed from its base state, such as for very large forcing or perturbed physics simulations. In addition, past analyses have not produced kernels relating to prognostic cloud variables because of strong nonlinearities in their relationship to radiative forcing. A new methodology is presented that allows for fast statistical optimizing of existing kernels such that accuracy is increased for significantly altered climatologies. International Satellite Cloud Climatology Project (ISCCP) simulator output is used to relate changes in cloud-type histograms to radiative fluxes. With minimal additional computation, an individual set of kernels is created for each climate experiment such that climate feedbacks can be reliably estimated even in significantly perturbed climates. This methodology is applied to successive generations of the Community Atmosphere Model (CAM). Increased climate sensitivity in CAM5 is shown to be due to reduced negative stratus and stratocumulus feedbacks in the tropics and midlatitudes, strong positive stratus feedbacks in the southern oceans, and a strengthened positive longwave cirrus feedback. Results also suggest that CAM5 exhibits a stronger surface albedo feedback than its predecessors, a feature not apparent when using a single kernel. Optimized kernels for CAM5 suggest weaker global-mean shortwave cloud feedback than one would infer from using the original kernels and an adjusted cloud radiative forcing methodology. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Climate is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1175/JCLI-D-11-00726.1 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 18 StartPage: 7607 Subjects: – SubjectFull: Radiative forcing Type: general – SubjectFull: Computer simulation of climate change Type: general – SubjectFull: General circulation model Type: general – SubjectFull: Kernel (Mathematics) Type: general – SubjectFull: Histograms Type: general – SubjectFull: Stratocumulus clouds Type: general Titles: – TitleFull: Model-Specific Radiative Kernels for Calculating Cloud and Noncloud Climate Feedbacks. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Sanderson, Benjamin M. – PersonEntity: Name: NameFull: Shell, Karen M. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 08948755 Numbering: – Type: volume Value: 25 – Type: issue Value: 21 Titles: – TitleFull: Journal of Climate Type: main |
| ResultId | 1 |
