Late Holocene anti-phase change in the East Asian summer and winter monsoons

Abstract

Changes in East Asian summer and winter monsoon intensity have played a pivotal role in the prosperity and decline of society in the past, and will be important for future climate scenarios. However, the phasing of changes in the intensity of East Asian summer and winter monsoons on millennial and centennial timescales during the Holocene is unclear, limiting our ability to understand the factors driving past and future changes in the monsoon system. Here, we present a high resolution (up to multidecadal) loess record for the last 3.3 ka from the southern Chinese Loess Plateau that clearly demonstrates the relationship between changes in the intensity of the East Asian summer and winter monsoons, particularly at multicentennial scales. At multimillennial scales, the East Asian summer monsoon shows a steady weakening, while the East Asian winter monsoon intensifies continuously. At multicentennial scales, a prominent ~700-800 yr cycle in the East Asian summer and winter monsoon intensity is observed, and here too the two monsoons are anti-phase. We conclude that multimillennial changes are driven by Northern Hemisphere summer insolation, while multicentennial changes can be correlated with solar activity and changing strength of the Atlantic meridional overturning circulation.

Decadal‐ to Centennial‐Scale East Asian Summer Monsoon Variability Over the Past Millennium: An Oceanic Perspective

“…The diatom‐based reconstructed winter sea surface temperature in the Okinawa Trough (Li et al, ) also shows striking similarity to the Hwajinpo record (Figure ), even though there are slight age discrepancies for Events 1 and 4. Higher winter sea surface temperature is associated with a weakened East Asian winter monsoon (EAWM; Li et al, ), and an inverse relationship between the centennial‐scale variabilities of the EAWM and the EASM was previously reported (Kang et al, ; Sagawa et al, ). Among Chinese continental records, the Wanxiang Cave stalagmite record (Zhang et al, ) shows the greatest overall similarity with the Lake Hwajinpo record including all four events, while many other Chinese continental records do not show substantial similarity (F. Chen et al, ; Chu et al, ; Wang et al, ; Yi et al, ; Zheng et al, ; Figure ).…”

“…Enhanced Walker circulation can result in more moisture transportation to the Asian summer monsoon region and thus more precipitation there (Ning et al, 2017;Wang et al, 2013). However, this negative AMOC-EASM relationship is opposite to what is anticipated (Haug et al, 2001;Kang et al, 2018;Sun et al, 2011;Zhang & Delworth, 2005), and thus, further observational and modeling studies are critically needed.…”

Nanosized Authigenic Magnetite and Hematite Particles in Mature‐Paleosol Phyllosilicates: New Evidence for a Magnetic Enhancement Mechanism in Loess Sequences of China

“…The magnetic susceptibility of modern soils may provide a hint regarding the timing of pedogenic ferrimagnet formation. Magnetic susceptibility reaches mature‐paleosol values (>100 × 10 −8 kg −1 ) at a near‐surface layer (Kang et al, 2018; S. Yang et al, 2015) and have a linear relationship with proximal‐site modern precipitation (Balsam et al, 2011; Maher & Thompson, 1995). Thus, most pedogenic ferrimagnets form near the surface.…”

“…Thus, most pedogenic ferrimagnets form near the surface. In addition, centennial‐scale antiphase changes of magnetic susceptibility and eolian grain size (proxies of East Asian summer and winter monsoons, respectively) for the late Holocene (Kang et al, 2018) and middle Pleistocene (Ueno et al, 2019) suggest that pedogenic ferrimagnet formation was nearly syndepositional. Therefore, it is plausible that authigenic magnetic minerals formed within phyllosilicates shortly after dust deposition.…”

Asian Winter Monsoon Imprint on Holocene SST Changes at the Northern Coast of the South China Sea

“…Because the divergence of dry air from the Siberia‐Mongolia continent enables the AWM to effectively redistribute a massive amount of aeolian dust and aerosol in boreal cold months (Bollasina et al, ; Li et al, ), analyses of grain size, mineralogical, and geochemical proxies from Chinese loess deposits are commonly carried out to determine AWM intensity (Kang et al, ; Li & Morrill, ; Stevens et al, ). Paleorecords at these individual sites are helpful to offer important insight into AWM evolution, but collectively, they point out controversies in terms of not only general AWM structures over the Holocene but also multicentennial to millennial scale variations within this specific interval (Hao et al, ; Li & Morrill, ; Kang et al, ; Xia et al, ). Furthermore, at Huguangyan Maar Lake near the northern coast of the South China Sea (SCS), opposite temporal features of Holocene AWM strength have been inferred from magnetic susceptibility/the S ratio (Yancheva et al, ) and diatom assemblages (Wang et al, ), whereas climate model simulations tend to support the diatom view of a weakening AWM toward the present (Wen et al, ).…”