Spatially heterogeneous responses of climate in East Asia to insolation, CO2 and ice sheets during MIS-5
(2023) 21st Congress of the International Union for Quaternary Research (INQUA) — Location: Roma, Italy (13.July.2023)
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- Marine Isotope Stage (MIS) 5, lasting from ~130 to ~70 thousand years before present (ka BP), is characterized by climate oscillations consisting of three interstadials and two stadials. Many climate simulations have been performed for the warmest MIS-5e period, but few has been made to cover the entire MIS-5 to investigate the climate variability during this long period. To study the relative impacts of insolation, CO2 and Northern Hemisphere ice sheets on the internal variations within MIS-5 and spatial variations of the East Asian climate, two sets of snapshot simulations with different combinations of forcings by a step of 2 ka covering the whole MIS-5 period are performed with HadCM3. Moisture budget analysis is carried out to investigate the processes related to changes in summer precipitation. Our results show that EASM climate in different subregions have different sensitivity to astronomical forcing, CO2, and ice sheets. The variability of temperature and precipitation within MIS-5 is mainly controlled by precession with strongly pronounced sub-stages of MIS-5 which correspond to precession minima and maxima, but their magnitudes are modulated by CO2 and ice sheets. Within the range of its variations during MIS-5, the CO2 concentration can cause similar degree of warming as insolation. However, the influence of CO2 on precipitation is much weaker than the influence of insolation, and the relationship between summer precipitation and CO2 is not statistically significant in most subregions in East Asia. Insolation and CO2 affect the summer precipitation by the dynamic and thermodynamic processes, respectively. Although ice sheets induce large cooling in the mid-high latitudes of both hemispheres, their impact on the precipitation and temperature in East Asia is quite small as compared to the impact of insolation, varying between regions and sensitive to the area and height of the ice sheets and the background insolation. Ice sheets influence the EASM precipitation mainly through the vertical dynamic processes which is strongly associated with the ice sheet-induced wave train at the hemisphere scale.
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Lyu, A., & Yin, Q. (2023). Spatially heterogeneous responses of climate in East Asia to insolation, CO2 and ice sheets during MIS-5. 21st Congress of the International Union for Quaternary Research (INQUA), Roma, Italy. https://hdl.handle.net/2078.5/268736