Forcing mechanisms of the Indian Ocean monsoon

Clemens, Steven C.; Prell, Warren L; Murray, David; Shimmield, Graham; Weedon, Graham P.

doi:10.1038/353720a0

Cited by 574 publications

(339 citation statements)

References 32 publications

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“…Our results on monsoon-driven maxima in fluvial nutrient supply and summer upwelling during glacial Terminations I and II match the common expectations on the variability of the monsoon, expectations which are based on (1) the orbital periodicities in the intensity of the Indian monsoon, deduced from sediment records from the Arabian Sea (Clemens et al, 1991;Sirocko et al, 1996), and (2) on atmospheric climate modeling (Prell and Kutzbach, 1987;Kutzbach and Gallimore, 1988;Kutzbach et al, 1996).…”

Section: Variations In the Fertility Of The South China Sea (Premise 6)supporting

confidence: 71%

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

et al. 1999

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Based on the study of 10 sediment cores and 40 core-top samples from the South China Sea (SCS) we obtained proxy records of past changes in East Asian monsoon climate on millennial to bidecadal time scales over the last 220,000 years. Climate proxies such as global sea level, estimates of paleotemperature, salinity, and nutrients in surface water, ventilation of deep water, paleowind strength, freshwater lids, fluvial and=or eolian sediment supply, and sediment winnowing on the sea floor were derived from planktonic and benthic stable-isotope records, the distribution of siliciclastic grain sizes, planktonic foraminifera species, and the U K 37 biomarker index. Four cores were AMS-14 C-dated. Two different regimes of monsoon circulation dominated the SCS over the last two glacial cycles, being linked to the minima and maxima of Northern Hemisphere solar insolation. (1) Glacial stages led to a stable estuarine circulation and a strong O 2 -minimum layer via a closure of the Borneo sea strait. Strong northeast monsoon and cool surface water occurred during winter, in part fed by an inflow from the north tip of Luzon. In contrast, summer temperatures were as high as during interglacials, hence the seasonality was strong. Low wetness in subtropical South China was opposed to large river input from the emerged Sunda shelf, serving as glacial refuge for tropical forest. (2) Interglacials were marked by a strong inflow of warm water via the Borneo sea strait, intense upwelling southeast of Vietnam and continental wetness in China during summer, weaker northeast monsoon and high sea-surface temperatures during winter, i.e. low seasonality. On top of the long-term variations we found millennial-to centennial-scale cold and dry, warm and humid spells during the Holocene, glacial Terminations I and II, and Stage 3. The spells were coeval with published variations in the Indian monsoon and probably, with the cold Heinrich and warm Dansgaard-Oeschger events recorded in Greenland ice cores, thus suggesting global climatic teleconnections. Holocene oscillations in the runoff from South China centered around periodicities of 775 years, ascribed to subharmonics of the 1500-year cycle in oceanic thermohaline circulation. 102=84-year cycles are tentatively assigned to the Gleissberg period of solar activity. Phase relationships among various monsoon proxies near the onset of Termination IA suggest that summer-monsoon rains and fluvial runoff from South China had already intensified right after the last glacial maximum (LGM) insolation minimum, coeval with the start of Antarctic ice melt Wang et al. / Marine Geology 156 (1999) prior to the δ 18 O signals of global sea-level rise. Vice versa, the strength of winter-monsoon winds decreased in short centennial steps only 3000-4000 years later, along with the melt of glacial ice sheets in the Northern Hemisphere.

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Section: Variations In the Fertility Of The South China Sea (Premise 6)supporting

confidence: 71%

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

et al. 1999

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“…That is, during the summer (southwesterly) monsoon winds, a high surface pressure develops over the cool western Pacific and a low surface pressure develops over the much warmer Asian continent, while during the winter (northeasterly) monsoon winds, a high surface pressure forms over the cold northern Asian continent and a low surface pressure forms over the warm western Pacific [Ding, 1994]. Associated with these large-scale, season-dependent monsoon wind patterns, the surface ocean circulation of the South China Sea (SCS) has been characterized as having monsoon-driven patterns [Wyrtki, 1961;Fang and Yu, 1981;Shaw, 1989Shaw, , 1991 [Clemens et al, 1991] revealed that monsoon variations are externally forced by solar radiation and are internally phaselocked to the latent evaporation of warm waters from the subtropical Indian Ocean. While these have been the primary factors controlling monsoon patterns, during the last glacial stage the intensity of the winter monsoon has increased in the Indian Ocean [Duplessy, 1982].…”

Section: Introductionmentioning

confidence: 99%

Ice‐volume forcing of winter monsoon climate in the South China Sea

Chen¹,

Huang²

1998

Paleoceanography

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“…The speleothem d 18 O records over Asia seem to be forced mainly and directly by local orbitally forced insolation [3][4][5]9,20,21 . On the contrary, a large variety of other Indo-Asian summer monsoonal records (marine and continental records documenting winds and precipitation) suggest a sensitivity to northern hemisphere summer sensible heating (insolation), the timing of energy release from the southern hemisphere Indian Ocean and the timing of global ice-volume minima 6,7,[11][12][13][14]16 .…”

mentioning

confidence: 99%

“…8). Similarly, the monsoon winds could be affected by such ocean internal feedback not only from the Pacific 15 , but also from the southern Indian Ocean 6,7,[11][12][13][14]16,29 and lead to different timing. Our study therefore highlights a complex Asian monsoon dynamic with distinct response inside the monsoon system.…”

mentioning

confidence: 99%

“…These deposits have been widely interpreted as records of changing intensity of the summer monsoon precipitation at orbital scales. However, interpretation of the speleothem d 18 O record is complex and is a subject of considerable debate [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] . Studies point to the potential control of seasonality, as well as large-scale atmospheric circulation effects in addition to the amount of Asian summer monsoonal rainfall on the d 18 O signal 11,12,17,18 .…”

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confidence: 99%

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Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model

2014

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The Asian summer monsoon dynamics at the orbital scale are a subject of considerable debate. The validity of Asian speleothem d 18 O records as a proxy for summer monsoon intensity is questioned together with the ultimate forcing and timing of the monsoon. Here, using the results of a 150,000-year transient simulation including water isotopes, we demonstrate that Asian speleothem d 18 O records are not a valid proxy for summer monsoon intensity only at the orbital timescale. Rather, our results show that these records reflect annual variations in hydrologic processes and circulation regime over a large part of the Indo-Asian region. Our results support the role of internal forcing, such as sea surface temperature in the equatorial Pacific, to modulate the timing of monsoon precipitation recorded in paleo-proxies inside the Asian region.

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Forcing mechanisms of the Indian Ocean monsoon

Cited by 574 publications

References 32 publications

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

Ice‐volume forcing of winter monsoon climate in the South China Sea

Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model

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