Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies
Over the 20th and 21st centuries, both anthropogenic greenhouse gas increases and changes in anthropogenic aerosols have affected rainfall in the Sahel. Using multiple characteristics of Sahel precipitation, we construct a multivariate fingerprint that allows us to distinguish between the model-pred...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ab858e |
| _version_ | 1797747480059707392 |
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| author | Kate Marvel Michela Biasutti Céline Bonfils |
| author_facet | Kate Marvel Michela Biasutti Céline Bonfils |
| author_sort | Kate Marvel |
| collection | DOAJ |
| description | Over the 20th and 21st centuries, both anthropogenic greenhouse gas increases and changes in anthropogenic aerosols have affected rainfall in the Sahel. Using multiple characteristics of Sahel precipitation, we construct a multivariate fingerprint that allows us to distinguish between the model-predicted responses to greenhouse gases and anthropogenic aerosols. Models project the emergence of a detectable signal of aerosol forcing in the middle of the 20th century and a detectable signal of greenhouse gas forcing at the beginning of the 21st. However, the signals of both aerosol and greenhouse gas forcing in observations emerge earlier and are stronger than in the models, far stronger in the case of aerosols. The similarity between the response to aerosol forcing and the leading mode of internal variability makes it difficult to attribute this model-observation discrepancy to errors in the forcing, errors in the forced response, model inability to capture the amplitude of internal variability, or some combination of these. For greenhouse gases, however, the forced response is distinct from internal variability as estimated by models, and the observations are largely commensurate with the model projections. |
| first_indexed | 2024-03-12T15:52:09Z |
| format | Article |
| id | doaj.art-c5afc677c03c4bc29e7d132aa8ccdfd3 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:52:09Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-c5afc677c03c4bc29e7d132aa8ccdfd32023-08-09T15:08:02ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-0115808402310.1088/1748-9326/ab858eFingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepanciesKate Marvel0Michela Biasutti1Céline Bonfils2NASA Goddard Institute for Space Studies , New York, NY, United States of America; Department of Applied Mathematics and Applied Physics, Columbia University , New York, NY, United States of AmericaLamont-Doherty Earth Observatory, Columbia University , Palisades, NY, United States of AmericaLawrence Livermore National Laboratory , Livermore, CA, United States of AmericaOver the 20th and 21st centuries, both anthropogenic greenhouse gas increases and changes in anthropogenic aerosols have affected rainfall in the Sahel. Using multiple characteristics of Sahel precipitation, we construct a multivariate fingerprint that allows us to distinguish between the model-predicted responses to greenhouse gases and anthropogenic aerosols. Models project the emergence of a detectable signal of aerosol forcing in the middle of the 20th century and a detectable signal of greenhouse gas forcing at the beginning of the 21st. However, the signals of both aerosol and greenhouse gas forcing in observations emerge earlier and are stronger than in the models, far stronger in the case of aerosols. The similarity between the response to aerosol forcing and the leading mode of internal variability makes it difficult to attribute this model-observation discrepancy to errors in the forcing, errors in the forced response, model inability to capture the amplitude of internal variability, or some combination of these. For greenhouse gases, however, the forced response is distinct from internal variability as estimated by models, and the observations are largely commensurate with the model projections.https://doi.org/10.1088/1748-9326/ab858eprecipitationSahelaerosolsgreenhouse gasesdetection and attribution |
| spellingShingle | Kate Marvel Michela Biasutti Céline Bonfils Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies Environmental Research Letters precipitation Sahel aerosols greenhouse gases detection and attribution |
| title | Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies |
| title_full | Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies |
| title_fullStr | Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies |
| title_full_unstemmed | Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies |
| title_short | Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies |
| title_sort | fingerprints of external forcings on sahel rainfall aerosols greenhouse gases and model observation discrepancies |
| topic | precipitation Sahel aerosols greenhouse gases detection and attribution |
| url | https://doi.org/10.1088/1748-9326/ab858e |
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