EGU21-1051
https://doi.org/10.5194/egusphere-egu21-1051
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Diverse Regional Sensitivity of Summer Precipitation in East Asia to Ice Volume, CO2 and Astronomical Forcing

Anqi Lyu1, Qiuzhen Yin1, Michel Crucifix1, and Youbin Sun2,3
Anqi Lyu et al.
  • 1Georges Lemaître Center for Earth and Climate Research, Earth and Life Institute, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
  • 2State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xian, China
  • 3CAS Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, 710061 Xian, China

The East Asian summer monsoon (EASM) is an important component of the climate system and it influences about one-third of the world’s population. Numerous paleoclimate records and climate simulations have been used to study its long-term evolution and response to different forcings. The strong regional dependence of the EASM variation questions the relative role of ice sheets and insolation on the EASM precipitation in different sub-regions in East Asia. A Gaussian emulator, which was generated and calibrated by interpolating the outputs of 61 snapshot simulations performed with the model HadCM3, is used to quantitatively assess how astronomical forcing, CO2 and northern hemisphere ice sheets affect the variation of the summer precipitation over the last 800 ky. Our results show that in the north of 25°N of the EASM domain, the variation of the summer precipitation is dominated by precession and insolation. This leads to strong 23-ky cycles in the summer precipitation. However, in the southern part (south of 25°N), the impact of ice volume becomes more important, leading to strong 100-ky cycles. Ice sheets influence the summer precipitation in the south mainly through its control on the location of the Intertropical Convergence Zone (ITCZ) which is very sensitive to ice volume. ITCZ is shifted significantly to the south under large ice sheets conditions. Therefore, the region under control of the ITCZ is more sensitive to the influence of ice volume than other regions. Our results also show that obliquity and CO2 have relatively small effect on the summer precipitation as compared to precession and ice sheets.

How to cite: Lyu, A., Yin, Q., Crucifix, M., and Sun, Y.: Diverse Regional Sensitivity of Summer Precipitation in East Asia to Ice Volume, CO2 and Astronomical Forcing, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1051, https://doi.org/10.5194/egusphere-egu21-1051, 2021.

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