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South China Sea hydrological changes and Pacific Walker Circulation variations over the last millennium.

Yan H, Sun L, Oppo DW, Wang Y, Liu Z, Xie Z, Liu X, Cheng W - Nat Commun (2011)

Bottom Line: Here we show that north-south ITCZ migration was not the only mechanism of tropical Pacific hydrologic variability during the last millennium, and that PWC variability profoundly influenced tropical Pacific hydrology.Our downcore grain size reconstructions indicate that this site received less precipitation during relatively warm periods, AD 1000-1400 and AD 1850-2000, compared with the cool period (AD 1400-1850).Including our new reconstructions in a synthesis of tropical Pacific records results in a spatial pattern of hydrologic variability that implicates the PWC.

View Article: PubMed Central - PubMed

Affiliation: Institute of Polar Environment, Department of Earth and Space Science, University of Science and Technology of China, Hefei, Anhui 230026, China.

ABSTRACT
The relative importance of north-south migrations of the intertropical convergence zone (ITCZ) versus El Niño-Southern Oscillation and its associated Pacific Walker Circulation (PWC) variability for past hydrological change in the western tropical Pacific is unclear. Here we show that north-south ITCZ migration was not the only mechanism of tropical Pacific hydrologic variability during the last millennium, and that PWC variability profoundly influenced tropical Pacific hydrology. We present hydrological reconstructions from Cattle Pond, Dongdao Island of the South China Sea, where multi-decadal rainfall and downcore grain size variations are correlated to the Southern Oscillation Index during the instrumental era. Our downcore grain size reconstructions indicate that this site received less precipitation during relatively warm periods, AD 1000-1400 and AD 1850-2000, compared with the cool period (AD 1400-1850). Including our new reconstructions in a synthesis of tropical Pacific records results in a spatial pattern of hydrologic variability that implicates the PWC.

No MeSH data available.


Geographic context for the present study.Map showing modern locations of the ITCZ in July and January6. Locations of this study (W1, Dongdao Island) and other hydrology records near the northern limit of western Pacific ITCZ (W45, W54, W620). The dark cell represents the PWC. Areas in equatorial Pacific with correlation coefficient between SOI and precipitation above 0.6 are marked in red (named PA) and below −0.6 are marked in blue (named NA)3. Locations of the rainfall records in the PA of western Pacific (W1-our South China Sea records, W2-Indonesia67 and W3-Indonesia8) and NA of eastern mid-tropical Pacific (M1-Washington Island17, E1-Galapagos13, E2-Ecuador12) are marked. Hydrology records from Peru (E31011) are also indicated. Locations that were drier/wetter during the Little Ice Age (LIA, ∼AD 1400–1850) than during the MCA, ∼AD 800–1300) are marked in red/blue.
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f1: Geographic context for the present study.Map showing modern locations of the ITCZ in July and January6. Locations of this study (W1, Dongdao Island) and other hydrology records near the northern limit of western Pacific ITCZ (W45, W54, W620). The dark cell represents the PWC. Areas in equatorial Pacific with correlation coefficient between SOI and precipitation above 0.6 are marked in red (named PA) and below −0.6 are marked in blue (named NA)3. Locations of the rainfall records in the PA of western Pacific (W1-our South China Sea records, W2-Indonesia67 and W3-Indonesia8) and NA of eastern mid-tropical Pacific (M1-Washington Island17, E1-Galapagos13, E2-Ecuador12) are marked. Hydrology records from Peru (E31011) are also indicated. Locations that were drier/wetter during the Little Ice Age (LIA, ∼AD 1400–1850) than during the MCA, ∼AD 800–1300) are marked in red/blue.

Mentions: To address the significance of changes in the PWC over the last millennium, we generated new records from Dongdao Island (16°39′–16°41′N, 112°43′–112°45′E), Xisha Islands, South China Sea (Fig. 1 and Supplementary Fig. S2). The results suggest that this site consistently received less precipitation during relatively warm periods, AD 1000–1400 and AD 1850–2000, and more rainfall during the cool period (AD 1400–1850). Including our new records in a synthesis of published records from the tropical Pacific rules out north–south ITCZ migration as the only mechanism of hydrologic variability at our core site. Our results suggest that changes in PWC profoundly influenced hydrology at our core site specifically, and in the tropics more generally, over the last millennium.


South China Sea hydrological changes and Pacific Walker Circulation variations over the last millennium.

Yan H, Sun L, Oppo DW, Wang Y, Liu Z, Xie Z, Liu X, Cheng W - Nat Commun (2011)

Geographic context for the present study.Map showing modern locations of the ITCZ in July and January6. Locations of this study (W1, Dongdao Island) and other hydrology records near the northern limit of western Pacific ITCZ (W45, W54, W620). The dark cell represents the PWC. Areas in equatorial Pacific with correlation coefficient between SOI and precipitation above 0.6 are marked in red (named PA) and below −0.6 are marked in blue (named NA)3. Locations of the rainfall records in the PA of western Pacific (W1-our South China Sea records, W2-Indonesia67 and W3-Indonesia8) and NA of eastern mid-tropical Pacific (M1-Washington Island17, E1-Galapagos13, E2-Ecuador12) are marked. Hydrology records from Peru (E31011) are also indicated. Locations that were drier/wetter during the Little Ice Age (LIA, ∼AD 1400–1850) than during the MCA, ∼AD 800–1300) are marked in red/blue.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104522&req=5

f1: Geographic context for the present study.Map showing modern locations of the ITCZ in July and January6. Locations of this study (W1, Dongdao Island) and other hydrology records near the northern limit of western Pacific ITCZ (W45, W54, W620). The dark cell represents the PWC. Areas in equatorial Pacific with correlation coefficient between SOI and precipitation above 0.6 are marked in red (named PA) and below −0.6 are marked in blue (named NA)3. Locations of the rainfall records in the PA of western Pacific (W1-our South China Sea records, W2-Indonesia67 and W3-Indonesia8) and NA of eastern mid-tropical Pacific (M1-Washington Island17, E1-Galapagos13, E2-Ecuador12) are marked. Hydrology records from Peru (E31011) are also indicated. Locations that were drier/wetter during the Little Ice Age (LIA, ∼AD 1400–1850) than during the MCA, ∼AD 800–1300) are marked in red/blue.
Mentions: To address the significance of changes in the PWC over the last millennium, we generated new records from Dongdao Island (16°39′–16°41′N, 112°43′–112°45′E), Xisha Islands, South China Sea (Fig. 1 and Supplementary Fig. S2). The results suggest that this site consistently received less precipitation during relatively warm periods, AD 1000–1400 and AD 1850–2000, and more rainfall during the cool period (AD 1400–1850). Including our new records in a synthesis of published records from the tropical Pacific rules out north–south ITCZ migration as the only mechanism of hydrologic variability at our core site. Our results suggest that changes in PWC profoundly influenced hydrology at our core site specifically, and in the tropics more generally, over the last millennium.

Bottom Line: Here we show that north-south ITCZ migration was not the only mechanism of tropical Pacific hydrologic variability during the last millennium, and that PWC variability profoundly influenced tropical Pacific hydrology.Our downcore grain size reconstructions indicate that this site received less precipitation during relatively warm periods, AD 1000-1400 and AD 1850-2000, compared with the cool period (AD 1400-1850).Including our new reconstructions in a synthesis of tropical Pacific records results in a spatial pattern of hydrologic variability that implicates the PWC.

View Article: PubMed Central - PubMed

Affiliation: Institute of Polar Environment, Department of Earth and Space Science, University of Science and Technology of China, Hefei, Anhui 230026, China.

ABSTRACT
The relative importance of north-south migrations of the intertropical convergence zone (ITCZ) versus El Niño-Southern Oscillation and its associated Pacific Walker Circulation (PWC) variability for past hydrological change in the western tropical Pacific is unclear. Here we show that north-south ITCZ migration was not the only mechanism of tropical Pacific hydrologic variability during the last millennium, and that PWC variability profoundly influenced tropical Pacific hydrology. We present hydrological reconstructions from Cattle Pond, Dongdao Island of the South China Sea, where multi-decadal rainfall and downcore grain size variations are correlated to the Southern Oscillation Index during the instrumental era. Our downcore grain size reconstructions indicate that this site received less precipitation during relatively warm periods, AD 1000-1400 and AD 1850-2000, compared with the cool period (AD 1400-1850). Including our new reconstructions in a synthesis of tropical Pacific records results in a spatial pattern of hydrologic variability that implicates the PWC.

No MeSH data available.