Holocene EASM‐EAWM Relationship Across Different Timescales in CCSM3

Abstract

The East Asian summer monsoon and winter monsoon (EASM and EAWM) are two important components of the East Asian monsoon system. However, the relationship between the two components during the Holocene remains debated in the observation. Here, we use a set of simulations in CCSM3 to investigate the EASM‐EAWM relation across different timescales during the Holocene. It is shown that the intensities of EASM and EAWM are positively correlated at orbital timescale but negatively correlated from millennial down to multidecadal timescales. The positive correlation at orbital timescales is forced by the seasonal insolation forcing, while the negative correlation at millennial and shorter timescales is caused mainly by the internal variability of the Atlantic Meridional Overturning Circulation (AMOC) and the subsequent teleconnection to East Asia via land‐sea thermal contrast.

Migration of the Northern Boundary of the East Asian Summer Monsoon Over the Last 21,000 years

“…These changes contributed to a large‐scale warming over most of the Northern Hemisphere, especially over the North Atlantic (Figure ) (Shi & Yan, 2019; Wen et al., 2016). Furthermore, the temperature and wind fields over Eurasia are influenced by the AMOC through the westerly jet waveguide and associated circumglobal teleconnection (M. Yan et al., 2020). Over eastern China, the mid‐ and high latitudes experience a stronger warming than the low latitudes, where cooling even occurs generally between 120°E and 180°E (Figure 8a); hence, the meridional temperature gradient decreases.…”

Fundamental Shift From Summer to Winter of Holocene Rainfall Regime in the Tropics

“…The relationship between winter monsoon and summer monsoon during the Holocene has long‐term been debated by a large number of studies and can differ dramatically from millennial down to multidecadal timescales. Although the synchronous variations possibility at orbital/suborbital timescale in response to the seasonal contrast triggered by summer insolation has been proposed (Jia et al., 2015; Steinke et al., 2011; Wen et al., 2016; Yan et al., 2020, 2023), it can be excluded because an antiphase relationship between winter and summer monsoon variability at millennial to centennial timescales was both robust for the paleoclimate records and model simulations over the East Asia (Kang et al., 2020; Lan et al., 2020; Wen et al., 2016; Yan et al., 2020; Yancheva et al., 2007) and Southeast Asia (Huang et al., 2011; Griffiths et al., 2020; Figure S5 in Supporting Information ), which is possibly caused by the internal variability of the Atlantic Meridional Overturning Circulation and the subsequent teleconnection to East Asia via land‐sea thermal contrast (Yan et al., 2020). The evolutions of summer monsoon over these two regions illustrate the minor diversity but the common weakening trend during the Holocene (Griffiths et al., 2020; Wang et al., 2005).…”

Modulating and Resetting Impacts of Different Volcanic Eruptions on North Atlantic SST Variations

“…Furthermore, this study mainly focused on the influences of volcanic eruptions on NA SST, which is typically used to define AMO, but cannot fully represent the response of AMO to volcanic eruptions, especially on multidecadal scale. Moreover, due to the unique complex variability of AMO (Yan et al., 2021), it is still not possible for us to completely separate the influences of external forcings from the internal variability of AMO. Therefore, in spite of these limitations, current results can potentially serve as a reference on the interactions between AMO and external forcings, which deserve further investigations in the future (Zhang et al., 2019).…”