Non-linear intensification of Sahel rainfall as a possible dynamic response to future warming
- Projections of the response of Sahel rainfall to future global warming diverge significantly. Meanwhile, paleoclimatic records suggest that Sahel rainfall is capable of abrupt transitions in response to gradual forcing. Here we present climate modeling evidence for the possibility of an abrupt intensification of Sahel rainfall under future climate change. Analyzing 30 coupled global climate model simulations, we identify seven models where central Sahel rainfall increases by 40 to 300% over the 21st century, owing to a northward expansion of the West African monsoon domain. Rainfall in these models is non-linearly related to sea surface temperature (SST) in the tropical Atlantic and Mediterranean moisture source regions, intensifying abruptly beyond a certain SST warming level. We argue that this behavior is consistent with a self-amplifying dynamic-thermodynamical feedback, implying that the gradual increase in oceanic moisture availability under warming could trigger a sudden intensification of monsoon rainfall far inland of today'sProjections of the response of Sahel rainfall to future global warming diverge significantly. Meanwhile, paleoclimatic records suggest that Sahel rainfall is capable of abrupt transitions in response to gradual forcing. Here we present climate modeling evidence for the possibility of an abrupt intensification of Sahel rainfall under future climate change. Analyzing 30 coupled global climate model simulations, we identify seven models where central Sahel rainfall increases by 40 to 300% over the 21st century, owing to a northward expansion of the West African monsoon domain. Rainfall in these models is non-linearly related to sea surface temperature (SST) in the tropical Atlantic and Mediterranean moisture source regions, intensifying abruptly beyond a certain SST warming level. We argue that this behavior is consistent with a self-amplifying dynamic-thermodynamical feedback, implying that the gradual increase in oceanic moisture availability under warming could trigger a sudden intensification of monsoon rainfall far inland of today's core monsoon region.…
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| Author details: | Jacob ScheweORCiD, Anders LevermannORCiDGND |
|---|---|
| URN: | urn:nbn:de:kobv:517-opus4-419114 |
| DOI: | https://doi.org/10.25932/publishup-41911 |
| Title of parent work (English): | Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe |
| Publication series (Volume number): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (630) |
| Publication type: | Postprint |
| Language: | English |
| Date of first publication: | 2019/02/19 |
| Publication year: | 2017 |
| Publishing institution: | Universität Potsdam |
| Release date: | 2019/02/19 |
| Tag: | CMIP5; Holocene; West African monsoon; abrupt monsoon transitions; climate; jet; moisture-advection feedback; ocean |
| Issue: | 630 |
| Number of pages: | 11 |
| First page: | 495 |
| Last Page: | 505 |
| Source: | Earth System Dynamics 8 (2017) 3, pp. 495–505 DOI 10.5194/esd-8-495-2017 |
| Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät |
| DDC classification: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
| Peer review: | Referiert |
| Publishing method: | Open Access |
| License (German): |  CC-BY - Namensnennung 4.0 International |
