Hydroclimate changes related to thermal state of the tropical Pacific in the northern coast of the South China Sea since ∼8000 cal yr B.P.
Wu YQ, Yang XQ, Yin J, Fürsich F, Zhang TW, Liu CL (2022)
Publication Type: Journal article
Publication year: 2022
Journal
DOI: 10.1016/j.jop.2022.05.001
Abstract
Under the complex influences including the monsoonal climates and tropical hydrological cycle, the features and forcing mechanisms of precipitation changes in the tropical monsoon regions remain controversial. The northern coast of the South China Sea (NCSCS), connecting the South China Sea (SCS) and the Pearl River Estuary (PRE), is a critical area providing reliable tropical precipitation records and probing the possible forcing mechanism of tropical precipitation, benefitted from its high deposition rate and hydroclimatic sensitivity. Here, δ18O variations of planktonic (δ18OG. ruber) and benthic foraminifera (δ18OC. lobatulus) were investigated respectively to reconstruct a high-resolution low-latitude precipitation record from the core 17NH-NC3 in the NCSCS. The results show a distinct δ18O difference between δ18OG. ruber and δ18OC. lobatulus, not only with respect to values, but also with respect to trends in some time intervals. The clear difference between the planktonic and benthic foraminifera (Δδ18Ob-p) illustrates the significant vertical salinity stratification. And the temporal trend of Δδ18Ob-p indicates the degree of salinity stratification variated since the mid-Holocene. We assume that the degree of stratification in the NCSCS was mainly controlled by tropical precipitation changes. Thus, the trend of Δδ18Ob-p values could indicate the temporal change of the tropical precipitation. The precipitation record of our research area is closely related to the tropical atmosphere–ocean dynamics stimulated by sea surface temperature (SST) changes of the tropical Pacific zone, analogous to the El Niño–Southern Oscillation (ENSO) events. During the mid-Holocene (from 8260 to 5180 cal yr B.P.), the sustainable higher Δδ18Ob-p values (>1.23‰) suggested a large amount of precipitation, pointing to a sustained state of La Niña-like, which is associated with lasted higher difference between Western SST and Eastern SST (W-E SST gradient) in the equatorial Pacific. Since 5180 cal yr B.P., the decreasing Δδ18Ob-p indicates less low-latitude precipitation, which can be ascribed to an El Niño-like mean state arising from decreased W-E SST gradient. Our study provides a new continuous high-resolution archive of low-latitude precipitation in the tropical monsoon region since 8260 cal yr B.P. And this record highlights that the thermal state of the tropical Pacific most likely adjusted the low-latitude precipitation since the mid-Holocene.
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APA:
Wu, Y.Q., Yang, X.Q., Yin, J., Fürsich, F., Zhang, T.W., & Liu, C.L. (2022). Hydroclimate changes related to thermal state of the tropical Pacific in the northern coast of the South China Sea since ∼8000 cal yr B.P. Journal of Palaeogeography. https://doi.org/10.1016/j.jop.2022.05.001
MLA:
Wu, Yue Qin, et al. "Hydroclimate changes related to thermal state of the tropical Pacific in the northern coast of the South China Sea since ∼8000 cal yr B.P." Journal of Palaeogeography (2022).
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China (CN)