Intensification of the Walker and Hadley atmospheric circulations during the Pliocene–Pleistocene climate transition

Etourneau, Johan; Schneider, Robert; Blanz, Thomas; Martinez, Philippe

doi:10.1016/j.epsl.2010.06.010

Cited by 126 publications

(130 citation statements)

References 39 publications

Supporting

Mentioning

119

Contrasting

Order By: Relevance

“…1) (17), which represents a potential carrier of sediments from southern Africa to the core location. The studied site has been under the influence of this current at least for the last 500 ka (18)(19)(20)(21). In addition, the present-day source of silicoclastic sediment in core MD96-2098 mainly consists of Namibian dust and southwestern Atlantic clays (<20% Congo river clay input) (22).…”

Section: Resultsmentioning

confidence: 99%

Orbital-scale climate forcing of grassland burning in southern Africa

Daniau

Goñi

Martinez

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

136

106

View full text Add to dashboard Cite

Although grassland and savanna occupy only a quarter of the world's vegetation, burning in these ecosystems accounts for roughly half the global carbon emissions from fire. However, the processes that govern changes in grassland burning are poorly understood, particularly on time scales beyond satellite records. We analyzed microcharcoal, sediments, and geochemistry in a high-resolution marine sediment core off Namibia to identify the processes that have controlled biomass burning in southern African grassland ecosystems under large, multimillennial-scale climate changes. Six fire cycles occurred during the past 170,000 y in southern Africa that correspond both in timing and magnitude to the precessional forcing of north-south shifts in the Intertropical Convergence Zone. Contrary to the conventional expectation that fire increases with higher temperatures and increased drought, we found that wetter and cooler climates cause increased burning in the study region, owing to a shift in rainfall amount and seasonality (and thus vegetation flammability). We also show that charcoal morphology (i.e., the particle's length-to-width ratio) can be used to reconstruct changes in fire activity as well as biome shifts over time. Our results provide essential context for understanding current and future grassland-fire dynamics and their associated carbon emissions.

show abstract

Section: Resultsmentioning

confidence: 99%

Orbital-scale climate forcing of grassland burning in southern Africa

Daniau

Goñi

Martinez

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

136

106

View full text Add to dashboard Cite

show abstract

“…The simulated changes of atmospheric general circulations including Hadley and Walker circulations during Pliocene (Brierley et al, 2009; are also suggested by proxy data (e.g. Etourneau et al, 2010). Changes of thermohaline and wind-driven ocean general circulations (e.g.…”

Section: Discussionmentioning

confidence: 99%

Mid-Pliocene global climate simulation with MRI-CGCM2.3: set-up and initial results of PlioMIP Experiments 1 and 2

Kamae

Ueda

2012

Geosci. Model Dev.

View full text Add to dashboard Cite

Abstract. The mid-Pliocene (3.3 to 3.0 million yr ago), a globally warm period before the Quaternary, is recently attracting attention as a new target for paleoclimate modelling and data-model synthesis. This paper reports setups and results of experiments proposed in Pliocene Model Intercomparison Project (PlioMIP) using a global climate model, MRI-CGCM2.3. We conducted pre-industrial and mid-Pliocene runs by using the coupled atmosphere-ocean general circulation model (AOGCM) and its atmospheric component (AGCM) for the PlioMIP Experiments 2 and 1, respectively. In addition, we conducted two types of integrations in AOGCM simulation, with and without flux adjustments on sea surface. General characteristics of differences in the simulated mid-Pliocene climate relative to the preindustrial in the three integrations are compared. In addition, patterns of predicted mid-Pliocene biomes resulting from the three climate simulations are compared in this study. Generally, difference of simulated surface climate between AGCM and AOGCM is larger than that between the two AOGCM runs, with and without flux adjustments. The simulated climate shows different pattern between AGCM and AOGCM particularly over low latitude oceans, subtropical land regions and high latitude oceans. The AOGCM simulations do not reproduce wetter environment in the subtropics relative to the present-day, which is suggested by terrestrial proxy data. The differences between the two types of AOGCM runs are small over the land, but evident over the ocean particularly in the North Atlantic and polar regions.

show abstract

“…That hypothesis predicts that regional climate records for both hemispheres should contain a precession component that is not visible in the sea level and deep-sea δ 18 O b record and is supported by evidence from Laurentide Ice Sheet melt and iceberg-rafted debris of the East Antarctic ice sheet (Patterson et al, 2014;Shakun et al, 2016 Raymo et al (2006), this suggests that the NH obliquity forcing is the primary driver for the G-IG in the early Pleistocene, although we cannot exclude precession forcing as a contributing factor. Various studies indicate the importance of gradual CO 2 decline in the intensification of NHG (Kürschner et al, 1996;Seki et al, 2010;Bartoli et al, 2011) combined with the threshold effects of ice albedo (Lawrence et al, 2010;Etourneau et al, 2010) and land cover changes (Koenig et al, 2011). Simulations of four coupled 3-D ice models indicate that Antarctic ice volume increases respond primarily to sea level lowering, while Eurasian and North American ice sheet growth is initiated by temperature decrease (de Boer et al, 2012).…”

Section: Implications For the Intensification Of Northern Hemisphere mentioning

confidence: 99%

“…Causes include tectonics (Keigwin, 1982;Raymo, 1994;Haug and Tiedemann, 1998;Knies et al, 2014;Poore et al, 2006), orbital forcing dominated by obliquity-paced variability (Hays et al, 1976;Maslin et al, 1998;Raymo et al, 2006), and atmospheric CO 2 concentration decline (Pagani et al, 2010;Seki et al, 2010;Bartoli et al, 2011) driven by, for example, changes in ocean stratification that affected the biological pump (Haug et al, 1999). Changes were amplified by NH albedo changes (Lawrence et al, 2010), evaporation feedbacks (Haug et al, 2005), and possibly tropical atmospheric circulation change and breakdown of a permanent El Niño (Ravelo et al, 2004;Brierley and Fedorov, 2010;Etourneau et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

et al. 2018

View full text Add to dashboard Cite

Abstract. We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian ( ∼ 2.6-1.8 Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG) in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial-interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS) 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST), vegetation, relative sea level, and coastal influence.During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct warm-cold alterations are synchronous between land and sea, but lead the relative sea level change by 3000-8000 years. The record provides evPublished by Copernicus Publications on behalf of the European Geosciences Union. 398T. H. Donders et al.: Land-sea coupling of early Pleistocene glacial cycles idence for a dominantly Northern Hemisphere-driven cooling that leads the glacial buildup and varies on the obliquity timescale. Southward migration of Arctic surface water masses during glacials, indicated by cool-water dinoflagellate cyst assemblages, is furthermore relevant for the discussion on the relation between the intensity of the Atlantic meridional overturning circulation and ice sheet growth.

show abstract

Intensification of the Walker and Hadley atmospheric circulations during the Pliocene–Pleistocene climate transition

Cited by 126 publications

References 39 publications

Orbital-scale climate forcing of grassland burning in southern Africa

Orbital-scale climate forcing of grassland burning in southern Africa

Mid-Pliocene global climate simulation with MRI-CGCM2.3: set-up and initial results of PlioMIP Experiments 1 and 2

Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

Contact Info

Product

Resources

About