Coherent Changes of Southeastern Equatorial and Northern African Rainfall During the Last Deglaciation

TitleCoherent Changes of Southeastern Equatorial and Northern African Rainfall During the Last Deglaciation
Publication TypeJournal Article
Year of Publication2014
AuthorsOtto-Bliesner, Bette L., Russell James M., Clark Peter U., Liu Zhengyu, Overpeck Jonathan T., Konecky Bronwen, deMenocal Peter, Nicholson Sharon E., He Feng, and Lu Zhengyao
Abstract / Summary

During the last deglaciation, wetter conditions developed abruptly ~14,700 years ago in southeastern equatorial and northern Africa and continued into the Holocene. Explaining the abrupt onset and hemispheric coherence of this early African Humid Period is challenging due to opposing seasonal insolation patterns. In this work, we use a transient simulation with a climate model that provides a mechanistic understanding of deglacial tropical African precipitation changes. Our results show that meltwater-induced reduction in the Atlantic meridional overturning circulation (AMOC) during the early deglaciation suppressed precipitation in both regions. Once the AMOC reestablished, wetter conditions developed north of the equator in response to high summer insolation and increasing greenhouse gas (GHG) concentrations, whereas wetter conditions south of the equator were a response primarily to the GHG increase.

URLhttp://dx.doi.org/10.1126/science.1259531
DOI10.1126/science.1259531
Year of Publication: 2014
Publication Date: 12/2014

During the last deglaciation, wetter conditions developed abruptly ~14,700 years ago in southeastern equatorial and northern Africa and continued into the Holocene. Explaining the abrupt onset and hemispheric coherence of this early African Humid Period is challenging due to opposing seasonal insolation patterns. In this work, we use a transient simulation with a climate model that provides a mechanistic understanding of deglacial tropical African precipitation changes. Our results show that meltwater-induced reduction in the Atlantic meridional overturning circulation (AMOC) during the early deglaciation suppressed precipitation in both regions. Once the AMOC reestablished, wetter conditions developed north of the equator in response to high summer insolation and increasing greenhouse gas (GHG) concentrations, whereas wetter conditions south of the equator were a response primarily to the GHG increase.

DOI: 10.1126/science.1259531
Citation:
Otto-Bliesner, BL, JM Russell, PU Clark, Z Liu, JT Overpeck, B Konecky, P deMenocal, SE Nicholson, F He, and Z Lu.  2014.  "Coherent Changes of Southeastern Equatorial and Northern African Rainfall During the Last Deglaciation."  https://doi.org/10.1126/science.1259531.