Response of the Asian summer monsoons to idealized precession and obliquity forcing in a set of GCMs

Bosmans, Joyce; Erb, Michael P.; Dolan, Aisling M.; Drijfhout, Sybren; Tuenter, E.; Hilgen, F.J.; Edge, Deirdre; Pope, James O.; Lourens, Lucas Joost

doi:10.1016/j.quascirev.2018.03.025

Cited by 65 publications

(77 citation statements)

References 66 publications

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“…However, the change of regional precipitation patterns may not be the same as the orbital variations. For example, Pausata et al (2011) simulated climate during the Heinrich events and found no obvious precipitation changes in China, while our study and other simulations (Bosmans et al, 2018) for orbital forcing show substantial precipitation changes in China. There are already studies showing the coherency of Asian speleothem 18 O vanishes at scales shorter than millennial (Chu et al, 2012;Li et al, 2014;Wan et al, 2011;Zhang et al, 2019), and further investigations are needed to identify at which time scales the coherency disappears.…”

Section: Discussioncontrasting

confidence: 66%

“…Speleothem trace element ratios also suggest that low values of speleothem δ 18 O in central China can coincide with dryness instead of wetness in that region (Zhang et al, ). This, however, is not enough to reach a conclusion regarding central China receiving less precipitation in P min , since similar simulations with other models like EC‐Earth and GFDL‐CM2.1 do not clearly show less precipitation in central China (Bosmans et al, ). These models all show a northward migration of the East Asian monsoon circulation.…”

Section: Resultsmentioning

confidence: 79%

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Deciphering Oxygen Isotope Records From Chinese Speleothems With an Isotope‐Enabled Climate Model

Emile‐Geay

Tabor

et al. 2019

Paleoceanog and Paleoclimatol

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Speleothem 18 O is widely used to reconstruct past hydroclimate variability, particularly over Asia. However, the interpretation of this proxy is still in debate. While this proxy is originally interpreted as regional rainfall amount of the Asian monsoon, other studies have interpreted it as upstream monsoon rainfall or atmospheric circulation changes. To better understand the signal preserved in speleothems over various time scales, this study employs a state-of-the-art isotope-enabled climate model to quantify contributions to the oxygen isotope composition of precipitation ( 18 O P ) over China. Results suggest that orbital-scale speleothem 18 O variations at Chinese sites mainly record the meridional migration of the Asian monsoon circulation, accompanied by an early northward movement of the East Asian rain belt. At interannual scales, Chinese speleothem 18 O is also tied to the intensity of monsoonal circulation, via a change in moisture source locations: Enhanced moisture delivery from remote source regions leads to more negative 18 O P , particularly in late summer and early autumn. Our results have implications for the hydroclimatic interpretation of speleothem 18 O from Chinese caves and suggest that this interpretation is time scale dependent.

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Section: Discussioncontrasting

confidence: 66%

Section: Resultsmentioning

confidence: 79%

Deciphering Oxygen Isotope Records From Chinese Speleothems With an Isotope‐Enabled Climate Model

Emile‐Geay

Tabor

et al. 2019

Paleoceanog and Paleoclimatol

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“…The increases in precipitation over the Indian ocean during summer follow a 'warmergets-wetter' pattern (Xie et al, 2010;Huang et al, 2013), whereby SST patterns are the dominant mechanism for tropical precipitation response in areas where local warming in SSTs exceeds the tropical average (Xie et al, 2014). The results presented for orbital configurations specific to the individual interglacial events studied are supported by more idealised orbital forcing experiments completed by Bosmans et al (2018).…”

Section: How Does Hadcm3 Simulate the Indian Monsoon In The Pliocene mentioning

confidence: 53%

Indian monsoon variability in response to orbital forcing during the late Pliocene

Prescott

Haywood

Dolan

et al. 2019

Global and Planetary Change

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The Asian monsoon is a major component of the global climate system and can be divided into two subsystems, the Indian monsoon and the East Asian monsoon. Insights into monsoon behaviour and dynamics can be gained through studying past warm intervals in Earth's history. One such interval is the Pliocene epoch, specifically the mid-Piacenzian Warm Period (mPWP; 3.264-3.025 Ma). This time is characterised as a period of sustained warmth, with annual mean temperatures 2 to 3°C higher than the pre-industrial era. Studies have examined the East Asian monsoon during the mPWP from both a geological data and climate modelling perspective. However, there has been little investigation into the behaviour of the Indian monsoon. Using a coupled atmosphere-ocean global climate model (HadCM3), the Indian summer monsoon response to orbital forcing during the mPWP is studied. Of the simulated interglacial events (Marine Isotope Stages KM5c, KM3, K1 and G17), MIS KM5c is the only one with a near-modern orbital forcing. This experiment is compared to a pre-industrial simulation to determine the nature of the mPWP Indian summer monsoon in the absence of a different pattern if insolation forcing. The monsoon at MIS KM5c, is simulated to be stronger than preindustrial, with higher surface air temperatures and precipitation over land due to higher levels of CO2. MIS G17, K1, and KM3 represent interglacial events of similar magnitude with different insolation forcing than MIS KM5c. The Indian summer monsoon is simulated to be significantly stronger for the interglacials K1 and KM3, compared to KM5c. This is due to stronger precession forcing causing an increase in summer surface air temperature and precipitation. When combined with Pliocene geological boundary conditions, these results highlight the significant effect of orbital forcing on the strength of the Indian summer monsoon. The sensitivity of the Indian monsoon to orbital forcing has important implications for any parallels drawn between Pliocene and future monsoon behaviour.

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“…S10 and S11). Models with different levels of complexities: QTCM (Hsu et al, 2010), Quasi-geostrophic model EC-Bilt (Tuenter et al, 2003), GCM with slab ocean (Battisti et al, 2014) and finally the fully coupled model EC-Earth (Bosmans et al, 2018) have all shown a shift in precipitation between land and ocean, when subjected to the precessional forcing. However, there are no proxies for precipitation over oceans to verify this.…”

Section: Discussionmentioning

confidence: 99%

The response of tropical precipitation to Earth's precession: the role of energy fluxes and vertical stability

et al. 2019

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Abstract. The changes in Earth's precession have an impact on the tropical precipitation. This has been attributed to the changes in seasonal solar radiation at the top of the atmosphere. The primary mechanism that has been proposed is the change in thermal gradient between the two hemispheres. This may be adequate to understand the zonal mean changes, but cannot explain the variations between land and oceans. We have used a simple model of the intertropical convergence zone (ITCZ) to unravel how precipitation changes with precession. Our model attributes the changes in precipitation to the changes in energy fluxes and vertical stability. We include the horizontal advection terms in this model, which were neglected in the earlier studies. The final response of the land and oceans is a result of complex feedbacks triggered by the initial changes in the insolation. We find that the changes in precipitation over the land are mainly driven by changes in insolation, but over the oceans, precipitation changes on account of changes in surface fluxes and vertical stability. Hence insolation can be a trigger for changes in precipitation on orbital timescales, but surface energy and vertical stability play an important role too. The African monsoon intensifies during a precession minimum (higher summer insolation). This intensification is mainly due to the changes in vertical stability. The precipitation over the Bay of Bengal decreases for minimum precession. This is on account of a remote response to the enhanced convective heating to the west of the Bay of Bengal. This weakens the surface winds and thus leads to a decrease in the surface latent heat fluxes and hence the precipitation.

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Response of the Asian summer monsoons to idealized precession and obliquity forcing in a set of GCMs

Abstract: This is a repository copy of Response of the Asian summer monsoons to idealized precession and obliquity forcing in a set of GCMs.

Cited by 65 publications

References 66 publications

Deciphering Oxygen Isotope Records From Chinese Speleothems With an Isotope‐Enabled Climate Model

Deciphering Oxygen Isotope Records From Chinese Speleothems With an Isotope‐Enabled Climate Model

Indian monsoon variability in response to orbital forcing during the late Pliocene

The response of tropical precipitation to Earth's precession: the role of energy fluxes and vertical stability

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