Surface temperature control in the North and tropical Pacific during the last glacial maximum

Timmermann, Axel; Justino, Flávio; Jin, F.; Krebs, Uta; Goosse, Hugues

doi:10.1007/s00382-004-0434-9

Cited by 53 publications

(67 citation statements)

References 49 publications

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“…This history suggests that the climate of Sulawesi is highly sensitive to glacial-interglacial forcings, and that the region may experience nonlinear, threshold responses to changes in global climate boundary conditions. Climate modeling studies indicate that IPWP hydrology could respond to a variety of glacial-interglacial forcings including regional processes, particularly exposure of the Sunda Shelf during sea level minima (34), as well as global forcings, including changes in global temperature and atmospheric greenhouse gas concentrations (GHGs) and remote forcing from ice sheet albedo and topography (5,6). All of these forcings reached their minima or maxima during the LGM, potentially triggering threshold responses in regional hydroclimate.…”

Section: Discussionmentioning

confidence: 99%

“…Climate modeling studies indicate that both albedo and orographic forcing by the LGM ice sheet can alter tropical Pacific climate. Albedo forcing can alter the interhemispheric thermal gradient, shifting the ITCZ southward (37), and topographic forcing can alter westerly flow over the North Pacific, intensify northern trade wind circulation, and also force the ITCZ to migrate southward (6). The change in tropical winds and moisture convergence shift the locus of western tropical Pacific precipitation southward from equatorial sites such as Lake Towuti.…”

Section: Discussionmentioning

confidence: 99%

“…Climate models and theory predict that Indo-Pacific hydrology responds strongly to, and interacts with, glacial-interglacial climate variations (4)(5)(6). This prediction is partly borne out by terrestrial sedimentary records that suggest widespread drying across the IPWP during the Last Glacial Maximum (LGM; refs.…”

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confidence: 99%

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Glacial forcing of central Indonesian hydroclimate since 60,000 y B.P.

Russell

Vogel

Konecky

et al. 2014

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

138

188

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The Indo-Pacific warm pool houses the largest zone of deep atmospheric convection on Earth and plays a critical role in global climate variations. Despite the region's importance, changes in Indo-Pacific hydroclimate on orbital timescales remain poorly constrained. Here we present high-resolution geochemical records of surface runoff and vegetation from sediment cores from Lake Towuti, on the island of Sulawesi in central Indonesia, that continuously span the past 60,000 y. We show that wet conditions and rainforest ecosystems on Sulawesi present during marine isotope stage 3 (MIS3) and the Holocene were interrupted by severe drying between ∼33,000 and 16,000 y B.P. when Northern Hemisphere ice sheets expanded and global temperatures cooled. Our record reveals little direct influence of precessional orbital forcing on regional climate, and the similarity between MIS3 and Holocene climates observed in Lake Towuti suggests that exposure of the Sunda Shelf has a weaker influence on regional hydroclimate and terrestrial ecosystems than suggested previously. We infer that hydrological variability in this part of Indonesia varies strongly in response to high-latitude climate forcing, likely through reorganizations of the monsoons and the position of the intertropical convergence zone. These findings suggest an important role for the tropical western Pacific in amplifying glacial-interglacial climate variability.tropical Pacific | paleoclimate | geochemistry | paleoecology

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Glacial forcing of central Indonesian hydroclimate since 60,000 y B.P.

Russell

Vogel

Konecky

et al. 2014

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

138

188

View full text Add to dashboard Cite

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“…Orographic forcing of the glacial ice sheets over North America enhances the upper level stationary eddy momentum flux convergence at about 30°N, which leads to descending motion near 30°N and ascending motion around the equator. The resulting pressure gradient intensifies the northern trade wind circulation, which results in an enhancement of the oceanic subtropical cells, increased upwelling and colder sea surface conditions in the tropical and North Pacific [Timmermann et al, 2004]. Furthermore, the seasonal cycle of clouds generates a meridional asymmetry of net annual mean shortwave radiation on precessional timescales [Timmermann et al, 2007a].…”

Section: Introductionmentioning

confidence: 99%

Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones

et al. 2007

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[1] The tropical Pacific plays a central role in the climate system by providing large diabatic heating that drives the global atmospheric circulation. Quantifying the role of the tropics in late Pleistocene climate change has been hampered by the paucity of paleoclimate records from this region and the lack of realistic transient climate model simulations covering this period. Here we present records of hydrogen isotope ratios (dD) of alkenones from the Panama Basin off the Colombian coast that document hydrologic changes in equatorial South America and the eastern tropical Pacific over the past 27,000 years (a) and the past 3 centuries in detail. Comparison of alkenone dD values with instrumental records of precipitation over the past $100 a suggests that dD can be used as a hydrologic proxy. On long timescales our records indicate reduced rainfall during the last glacial period that can be explained by a southward shift of the mean position of the Intertropical Convergence Zone and an associated reduction of Pacific moisture transport into Colombia. Precipitation increases at $17 ka in concert with sea surface temperature (SST) cooling in the North Atlantic and the eastern tropical Pacific. A regional coupled model, forced by negative SST anomalies in the Caribbean, simulates an intensification of northeasterly trade winds across Central America, increased evaporative cooling, and a band of increased rainfall in the northeastern tropical Pacific. These results are consistent with the alkenone SST and dD reconstructions that suggest increasing precipitation and SST cooling at the time of Heinrich event 1.

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“…These studies demonstrated that the glacial wintertime atmospheric circulation in the northern hemisphere (NH) during the Last Glacial Maximum (LGM) was more strongly influenced by the direct influence of glacial topographic forcing than by any other effect such as albedo, orbital forcing, and CO 2 . For example, the topographic barrier provided by the presence of the Laurentide ice sheet over the northern part of the North American continent creates an upstream-blocking situation over the North Pacific, which significantly decelerates the westerlies (Justino et al 2005;Timmermann et al 2004). In addition, the ice sheet topography affects lee cyclogenesis over North America and generates stationary wave anomalies, which in turn play a key role in the baroclinic structure of the mean flow (Vettoretti et al 2000;Kageyama and Valdes 2000).…”

Section: Introductionmentioning

confidence: 99%

An Initial Intercomparison of Atmospheric and Oceanic Climatology for the ICE-5G and ICE-4G Models of LGM Paleotopography

et al. 2006

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This paper investigates the impact of the new ICE-5G paleotopography dataset for Last Glacial Maximum (LGM) conditions on a coupled model simulation of the thermal and dynamical state of the glacial atmosphere and on both land surface and sea surface conditions. The study is based upon coupled climate simulations performed with the ocean-atmosphere-sea ice model of intermediate-complexity Climate de Bilt-coupled large-scale ice-ocean (ECBilt-Clio) model. Four simulations focusing on the Last Glacial Maximum [21 000 calendar years before present (BP)] have been analyzed: a first simulation (LGM-4G) that employed the original ICE-4G ice sheet topography and albedo, and a second simulation (LGM-5G) that employed the newly constructed ice sheet topography, denoted ICE-5G, and its respective albedo. Intercomparison of the results obtained in these experiments demonstrates that the LGM-5G simulation delivers significantly enhanced cooling over Canada compared to the LGM-4G simulation whereas positive temperature anomalies are simulated over southern North America and the northern Atlantic. Moreover, introduction of the ICE-5G topography is shown to lead to a deceleration of the subtropical westerlies and to the development of an intensified ridge over North America, which has a profound effect upon the hydrological cycle. Additionally, two flat ice sheet experiments were carried out to investigate the impact of the ice sheet albedo on global climate. By comparing these experiments with the full LGM simulations, it becomes evident that the climate anomalies between LGM-5G and LGM-4G are mainly driven by changes of the earth's topography.

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Surface temperature control in the North and tropical Pacific during the last glacial maximum

Cited by 53 publications

References 49 publications

Glacial forcing of central Indonesian hydroclimate since 60,000 y B.P.

Glacial forcing of central Indonesian hydroclimate since 60,000 y B.P.

Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones

An Initial Intercomparison of Atmospheric and Oceanic Climatology for the ICE-5G and ICE-4G Models of LGM Paleotopography

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