气候变化领域集成服务门户(CCPortal): Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum

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DOI	10.1029/2023PA004767
	Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum
	Wubben, Evi; Spiering, Bianca R.; Veenstra, Tjerk; Bos, Remco; Wang, Zongyi; van Dijk, Joost; Raffi, Isabella; Witkowski, Jakub; Hilgen, Frederik J.; Peterse, Francien; Sangiorgi, Francesca; Sluijs, Appy
发表日期	2024
ISSN	2572-4517
EISSN	2572-4525
起始页码	39
结束页码	5
卷号	39 期号:5
英文摘要	Studying monsoon dynamics during past warm time periods such as the Miocene Climatic Optimum (MCO; similar to 16.9-14.5 Ma) could greatly aid in better projecting monsoon intensity, in the context of future greenhouse warming. However, studies on regional MCO temperature change and its effect on the monsoons during this time period are lacking. Here, we present the first high-resolution, low-latitude record of sea surface temperature (SST) and paleoceanographic change covering the Miocene Climatic Optimum, in the eastern equatorial Atlantic, at Ocean Drilling Program Site 959, based on TEX86 paleothermometry. SSTs were similar to 1.5 degrees C warmer at the onset of the MCO (16.9 Ma) relative to the pre-MCO (similar to 18.3-17.7 Ma). This warming was accompanied by a transient increase in %total organic carbon. Prior to the MCO, sediment composition, geochemical proxy data as well as dinoflagellate cyst assemblages imply a productive surface ocean at Site 959. Immediately following the MCO onset (similar to 16.9-16.5 Ma), we record an intensification of the West African Monsoon (WAM) characterized by higher amplitude variability in all proxy records on precession to obliquity timescales. We interpret increased orbital-scale SST, biogenic Ba and dinocyst assemblage variability to represent intensification of equatorial upwelling, forced by the WAM strength. Furthermore, higher SSTs during eccentricity maxima correlate to increased relative abundances of the warm and stratification-favoring dinocyst Polysphaeridium zoharyi, during periods of low WAM intensity. Finally, while long-term SSTs decline toward the middle Miocene, maximum SSTs and Polysphaeridium zoharyi abundances occur during MCO peak warming at similar to 15.6 Ma. The global climate during the Miocene Climatic Optimum (MCO) (similar to 16.9-14.5 Ma) was warm, perhaps similar to the future. Better understanding the climate system during this time period could aid in predicting future climate change. Tropical climates are the engine of global climate because they transport heat and moisture to higher latitudes with winds and ocean currents. Monsoons are an important feature of tropical climates. Importantly, continuous sea surface temperature reconstructions covering the MCO from the tropics are lacking. Here, we present an unprecedented resolution novel sea surface temperature record using sediments recovered in the eastern equatorial Atlantic Ocean which cover the MCO. Surface ocean temperatures rose by similar to 1.5 degrees C between the Early Miocene (similar to 18.3-17.7 Ma) and the onset of the MCO. Concomitantly, we record an increase in wind strength, surface ocean mixing and biological growth in the ocean, caused by a stronger West African Monsoon in this warmer climate. The monsoon strength is also strongly determined by variations in solar insolation, through periodic variations in the Earth's orbit. The recorded monsoon intensification with warming is consistent with projections of future monsoons under modern global warming. The first high-resolution tropical sea surface temperature record shows that the Miocene Climatic Optimum was similar to 1.5 degrees C warmer than the Early Miocene in the eastern equatorial Atlantic The West African Monsoon intensified following warming at similar to 17 Ma, resulting in variable surface ocean conditions forced by orbital cycles Intensification of the monsoon system caused increased dust supply and strong upwelling alternating with hyperstratification
英文关键词	Miocene Climatic Optimum; tropical sea surface temperature warming; West African Monsoon; dinoflagellate cysts; orbital climate variability
语种	英语
WOS研究方向	Geology ; Oceanography ; Paleontology
WOS类目	Geosciences, Multidisciplinary ; Oceanography ; Paleontology
WOS记录号	WOS:001215387300001
来源期刊	PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/306764
作者单位	Utrecht University; G d'Annunzio University of Chieti-Pescara; University of Szczecin
推荐引用方式 GB/T 7714	Wubben, Evi,Spiering, Bianca R.,Veenstra, Tjerk,et al. Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum[J],2024,39(5).
APA	Wubben, Evi.,Spiering, Bianca R..,Veenstra, Tjerk.,Bos, Remco.,Wang, Zongyi.,...&Sluijs, Appy.(2024).Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum.PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY,39(5).
MLA	Wubben, Evi,et al."Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum".PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 39.5(2024).