The Decadal Variability of the Global Monsoon Links to the North Atlantic Climate Since 1851

Abstract

To date, the decadal variability of the Global Monsoon (GM) has been mainly studied using instrumental data collected over the last 50 years, and further discussion has been hampered by the limited data length. Here, we present a coral δ18O record from the northern South China Sea, where the hydrology is related to the seasonal Intertropical Convergence Zone (ITCZ) migration, and we use this record to reconstruct the decadal migration of the ITCZ since 1851 A.D. Combining our record with a synthesis of monsoon records reveals an anti‐phase inter‐hemispheric variability of the GM over the last 150 years, indicating that the decadal‐scale hydrologic variability in the tropics is modulated by the meridional migration of the ITCZ. The plausible relationship observed between the decadal variability of the GM and the Atlantic Multidecadal Oscillation suggests that the decadal variability of tropical hydrological changes is likely linked to the climate perturbations in the North Atlantic.

Links Between the Coral δ13C Record of Primary Productivity Variations in the Northern South China Sea and the East Asian Winter Monsoon

“…As Yongxing Island (16.84°N, 112.33°E) is located far from the salinity front, the influence of river discharge at our study site should be very limited. Considering that the coral δ 18 O from the Xisha Islands could be used as a reliable proxy for salinity changes on decadal timescales (Han et al, ), we correlated the decadal variability of the coral ∆ δ 13 C with the δ 18 O values from the same coral colony over the past 150 years ( r = 0.22, n eff = 27.53, p adj = 0.13) (Figure S13). This result further confirmed the limited effect of river discharge on the δ 13 C values of the DIC at our study site.…”

Porites Coral on a Remote Reef Reveal Marine Phosphorus Biogeochemical Cycling Following Artificial Disturbance

“…Photosynthesis of endosymbiotic zooxanthellae was not responsible for the changes in coral δ 13 C, as evidenced by comparing the decadal variability of coral Δδ 13 C and local solar radiation (Han, Yu, Yan, Yan, et al, 2019). The absence of a correlation between coral Δδ 13 C and upper‐layer Luzon Strait transport indicated the limited contribution of ocean circulation to coral δ 13 C values (Han, Yu, Yan, Yan, et al, 2019). The increased coral δ 13 C values under a strong winter moon mean that the upwelled water from the deeper layer with lower δ 13 C values contributed little to the coral δ 13 C values (Han, Yu, Yan, Yan, et al, 2019).…”

“…The absence of a correlation between coral Δδ 13 C and upper‐layer Luzon Strait transport indicated the limited contribution of ocean circulation to coral δ 13 C values (Han, Yu, Yan, Yan, et al, 2019). The increased coral δ 13 C values under a strong winter moon mean that the upwelled water from the deeper layer with lower δ 13 C values contributed little to the coral δ 13 C values (Han, Yu, Yan, Yan, et al, 2019). In brief, by ruling out the influence of the kinetic effect, metabolic effect, river runoff from the mainland, and ocean circulation, our previous conclusion that the coral δ 13 C is a reliable proxy of marine primary productivity, by removing the oceanic 13 C Suess effect in study area, has been confirmed (Han, Yu, Yan, Yan, et al, 2019).…”

“…After experiencing a sustained decline, with a negative bias of ~1.4‰ contributed by the Suess effect and the EAWM from ~1920 to ~1960 CE (Han, Yu, Yan, Yan, et al, 2019), coral δ 13 C then exhibited a wave‐like rise and peaked in 1973 CE (Figure 2). Interestingly, coral δ 13 C and P/Ca were significantly and negatively correlated during 1851–1959 CE ( r = −0.34, p < 0.01) but positively correlated during 1960–2005 CE ( r = 0.56, p < 0.01) (Figure 3a).…”

“…In addition, a Nu plasma high‐resolution multicollection inductively coupled plasma mass spectrometer was used to date the U‐Th chemistry series. The analytical methods used herein followed those of Jiang et al (2018), Han, Yu, Yan, Deng, et al (2019), and Han, Yu, Yan, Yan, et al (2019) and were also elaborated in Text S1. The reliability of the coral geochemical data has been confirmed by Jiang et al (2018).…”