There is a scientific debate on the relationship between ancient winter and summer monsoons in East *** scholars think that East Asian winter and summer monsoons are anti-correlated,and others think *** this reason,th...
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There is a scientific debate on the relationship between ancient winter and summer monsoons in East *** scholars think that East Asian winter and summer monsoons are anti-correlated,and others think *** this reason,this study is motivated to assess their linkage from the paleoclimate simulation perspective,through analyzing the Last Glacial Maximum(LGM) and mid-Holocene(MH) climate simulated by CCSM3 *** to the present climate,the Aleutian low is found to be deepened and the East Asian winter monsoon(EAWM) is stronger during the LGM *** Pacific high in summer is noticed to be weakened and the East Asian summer monsoon(EASM) is weaker at the *** the MH,the Aleutian low and the Asian high in winter are intensified,and the Asian low and the Pacific high in summer are enhanced,indicating that the EAWM and EASM are both stronger than ***,the EAWM is not always negatively correlated to the *** relationship may be different at different geological *** can be obtained at least from the numerical simulation results that the EAWM and the EASM is negatively correlated during the cooling period,while positively correlated during the warming period.
To compare differences among the Medieval Warm Period (MWP), Little Ice Age (LIA), and 20th century global warming (20CW), six sets of transient and equilibrium simulations were generated using the climate system mode...
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To compare differences among the Medieval Warm Period (MWP), Little Ice Age (LIA), and 20th century global warming (20CW), six sets of transient and equilibrium simulations were generated using the climate system model FGOALS_gl. This model was developed by the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences. The results indicate that MWP warming is evident on a global scale, except for at mid-latitudes of the North Pacific. However, the magnitude of the warming is weaker than that in the 20th century. The warming in the high latitudes of the Northern Hemisphere is stronger than that in the Southern Hemisphere. The LIA cooling is also evident on a global scale, with a strong cooling over the high Eurasian continent, while the cooling center is over the Arctic domain. Both the MWP and the 20CW experiments exhibit the strongest warming anomalies in the middle troposphere around 200-300 hPa, but the cooling center of the LIA experiment is seen in the polar surface of the Northern Hemisphere. A comparison of model simulation against the reconstruction indicates that model's performance in simulating the surface air temperature changes during the warm periods is better than that during the cold periods. The consistencies between model and reconstruction in lower latitudes are better than those in high latitudes. Comparison of the inter-annual variability mode of East Asian summer monsoon (EASM) rainfall during the MWP, LIA and 20CW reveals a similar rainfall anomalies pattern. However, the time spectra of the principal component during the three typical periods of the last millennium are different, and the quasi-biannual oscillation is more evident during the two warm periods. At a centennial time scale, the external mode of the EASM variability driven by the changes of effective solar radiation is determined by the changes of large scale land-sea thermal con
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