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Abstract: Holocene climate records obtained from the Asian summer monsoon domain suggest a regionally-delineated response to changing summer monsoon. The interaction between the East Asian summer monsoon (EASM) and the Indian summer monsoon (ISM), two subsystems of the Asian summer monsoon, has been considered as a factor that explains those inconsistent Holocene climate records. However, this assumption is not valid when the relationship between the two subsystems is not clear. This paper presents a literature review regarding climate simulation of the Asian summer monsoon for testing the long-term relationship. The absolutely-dated Holocene speleothem records in the EASM domain and the ISM domain were compared to verify the simulation results. In addition, a unified monsoon index, which has a unified solid dynamic basis and is appropriate for different monsoon regions, was used in order to identify the modern relationship between the two subsystems. The speleothem records show more synchronous than asynchronous on the Holocene millennial-scale monsoon evolution, furthermore the two subsystems respond to the Younger Dryas (YD) and 8.2ka events in a similar way. However, these monsoon simulations roughly suggest that the two subsystems respond to Holocene climate change in different ways. While the simulations were mostly performed in a certain period of the Holocene, the speleothem records provided a relatively continuous Asian summer monsoon history. Therefore, time scales could affect the comparison between simulations and speleothem records. Then, we further discussed the interaction between the Asian monsoon subsystems according to simulations and modern monsoon indices. Overall, the relationship between the two subsystems is more complicated than synchronous or asynchronous, which is a dynamic relationship and related to the atmosphere–land–ocean–vegetation interaction. In addition, the relationship can vary over different time scales, and the links between time scales should be paid more attention to. Besides, the interaction between the westerly winds and the Asian summer monsoon in the mid-latitudes of East Asia will profoundly affect those areas in response to Holocene climate change. It is recommended that further research should be emphasized in dynamic mechanisms between the Asian summer monsoon subsystems and between the Asian monsoon and the westerly winds. [Copyright &y& Elsevier]

Abstract: The pattern of Holocene environmental changes in the Asian monsoon margin on a millennial timescale remains controversial. Based on lithological characteristics and sedimentological proxies, we reconstructed Holocene-effective humidity changes and the lake evolution of Huahai Lake in the marginal area of the Asian monsoon in the Hexi Corridor of NW China. Our results show that alluvial and aeolian deposition before 10.4 cal ka BP indicate an arid environment, that lacustrine deposition from 10.4 to 8.8 cal ka BP indicates a transition from an arid to a humid environment, and that lacustrine deposition from 8.8 to 5.5 cal ka BP occurred during the most humid conditions, indicated by proxy records (grain size, carbonate, TOC, and C/N). After 5.5 cal ka BP, a depositional hiatus implicates an arid environment in the late Holocene. Holocene environmental changes on millennial timescales in Huahai Lake imply that climate was arid to humid in the early Holocene, most humid in the mid-Holocene and arid in the late Holocene. These moisture changes were influenced by the Asian monsoon, particularly the transportation of water vapor by the Indian monsoon. In addition, these moisture changes could have been affected by westerly winds that could have contributed to the water vapor supply to this region during the mid-Holocene. The most humid conditions that occurred in the study area during the mid-Holocene may have been caused by strong westerlies and low levels of evaporation. [Copyright &y& Elsevier]

In the mid-latitude regions of the Asian continent, Zhuye Lake is located in the northwest margin of the Asian monsoon, where the modern climate is affected by the Asian monsoon and Westerlies. In this study, we investigated the absolutely dated Holocene records in Zhuye Lake for detecting the Holocene climate cycles. Totally, 14 C dates and 6 optically simulated luminescence (OSL) dates are obtained from the QTH01 and QTH02 sections. The proxies of grain-size, total organic carbon content (TOC), C/N and δC are used for wavelet analysis, and the results show obvious ∼256, ∼512 and ∼1024-year climate cycles, which are consistent with the Holocene millennial and centennial scale climate cycles in the typical Asian summer monsoon domain. In different parts of the Zhuye Lake, the Holocene sediments show variable climate cycles that are affected by the lake basin topography. In the Zhuye Lake, the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events. [ABSTRACT FROM AUTHOR]

Studies the age of formation of the mirabilite and sand wedges in the Hexi Corridor located in the transition zone of the Asian summer monsoon and westerly airflow. Paleoclimatic interpretation of the age formation; Mean annual air temperature in the area during the mirabilite's period of formation.