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| Gu, Sifan; Liu, Zhengyu; Zhang, Jiaxu; Rempfer, Johannes; Joos, Fortunat; Oppo, Delia W.. |
| Antarctic Intermediate Water (AAIW) plays important roles in the global climate system and the global ocean nutrient and carbon cycles. However, it is unclear how AAIW responds to global climate changes. In particular, neodymium isotopic composition (epsilon(Nd)) reconstructions from different locations from the tropical Atlantic have led to a debate on the relationship between northward penetration of AAIW into the tropical Atlantic and the Atlantic meridional overturning circulation (AMOC) variability during the last deglaciation. We resolve this controversy by studying the transient oceanic evolution during the last deglaciation using a neodymium-enabled ocean model. Our results suggest a coherent response of AAIW and AMOC: when AMOC weakens, the... |
| Tipo: Text |
Palavras-chave: AAIW; AMOC; Deglacial; Neodymium isotope; Paleocirculation tracer. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00495/60709/65334.pdf |
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| Jian, Zhimin; Wang, Yue; Dang, Haowen; Lea, David W.; Liu, Zhengyu; Jin, Haiyan; Yin, Yaqian. |
| The El Niño−Southern Oscillation (ENSO), which is tightly coupled to the equatorial thermocline in the Pacific, is the dominant source of interannual climate variability, but its long-term evolution in response to climate change remains highly uncertain. This study uses Mg/Ca in planktonic foraminiferal shells to reconstruct sea surface and thermocline water temperatures (SST and TWT) for the past 142 ky in a western equatorial Pacific (WEP) core MD01-2386. Unlike the dominant 100-ky glacial−interglacial cycle recorded by SST and δ18O, which echoes the pattern seen in other WEP sites, the upper ocean thermal gradient shows a clear half-precessional (9.4 ky or 12.7 ky) cycle as indicated by the reconstructed and simulated temperature (ΔT) and δ18O... |
| Tipo: Text |
Palavras-chave: Thermocline temperature; Half-precession; Western equatorial Pacific; Meridional gradient. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00614/72647/71649.pdf |
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| Gibbons, Fern T.; Oppo, Delia W.; Mohtadi, Mahyar; Rosenthal, Yair; Cheng, Jun; Liu, Zhengyu; Linsley, Braddock K.. |
| Evidence from geologic archives suggests that there were large changes in the tropical hydrologic cycle associated with the two prominent northern hemisphere deglacial cooling events, Heinrich Stadial 1 (HS1; similar to 19 to 15 kyr BP; kyr BP = 1000 yr before present) and the Younger Dryas (similar to 12.9 to 11.7 kyr BP). These hydrologic shifts have been alternatively attributed to high and low latitude origin. Here, we present a new record of hydrologic variability based on planktic foraminifera-derived delta O-18 of seawater (delta O-18(sw)) estimates from a sediment core from the tropical Eastern Indian Ocean, and using 12 additional delta O-18(sw) records, construct a single record of the dominant mode of tropical Eastern Equatorial Pacific and... |
| Tipo: Text |
Palavras-chave: Indo-Pacific; Eastern Equatorial Pacific; Delta O-18 of seawater; Deglaciation; Heat transport. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00496/60737/65207.pdf |
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| Marcott, Shaun A.; Clark, Peter U.; Padman, Laurie; Klinkhammer, Gary P.; Springer, Scott R.; Liu, Zhengyu; Otto-bliesner, Bette L.; Carlson, Anders E.; Ungerer, Andy; Padman, June; He, Feng; Cheng, Jun; Schmittner, Andreas. |
| Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2 C over a 1-2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Paleoclimatology; Abrupt climate change. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33819/32479.pdf |
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