Abstract Monsoonal water vapour transport is an active component of the hydrological cycle, which has a profound influence on regional climate changes. This study explored how far can the East Asian summer monsoon (EASM) transport water vapour to the west during the Holocene using published speleothem oxygen isotope (δ18O) records inferred from modern analogues of precipitation δ18O in the summer monsoon season (May to September) at mid-latitudes. Modern climate analyses suggest that there are two water vapour transport pathways to arid central Asia in the summer monsoon season: westerly transport and monsoonal easterly transport. Westerly transport from the North Atlantic and Arctic Oceans is associated with 18O-depleted water vapour, while monsoonal easterly transport from the tropical Indian Ocean, South China Sea, and East Asia is associated with 18O-enriched water vapour. The mixture of these water vapour dominates precipitation δ18O in arid central Asia from May to September. The difference of δ18O between precipitation in arid central Asia and the southern Urals reflects the penetration of monsoonal water vapour into arid central Asia. Speleothem δ18O records from Kesang Cave in the central Tianshan Mountains and Kinderlinskaya Cave in the southern Urals were therefore selected to indicate monsoonal water vapour transport into arid central Asia during the Holocene. Their differences suggest prominent monsoonal water vapour were transported to arid central Asia during the early Holocene, 8.2 ka BP event and late Holocene when the EASM was very weak. The results indicate that monsoonal water vapour could be transported at least as far west as the central Tianshan Mountains (∼81.75° E) in arid central Asia during the Holocene under weak EASM conditions rather than as previously supposed under strong EASM conditions. Although the amount of monsoonal water vapour is relatively less compared with that of westerly water vapour, it cannot be neglected because this source plays an important role in changes of precipitation and its δ18O in arid central Asia during the summer monsoon season.

中文翻译：

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全新世季风水汽对干旱中亚的渗透：同位素视角

摘要 季风水汽输送是水文循环的活跃组成部分，对区域气候变化有着深远的影响。本研究使用已发表的洞穴氧同位素 (δ18O) 记录，从夏季季风季节（5 月至 9 月）降水 δ18O 的现代类似物推断出的全新世期间，东亚夏季风 (EASM) 可将水汽输送到西方多远中纬度地区。现代气候分析表明，夏季季风季节有两条水汽输送途径到干旱的中亚：西风输送和季风东风输送。来自北大西洋和北冰洋的西风输送与 18O 耗尽的水蒸气有关，而来自热带印度洋、南海、东亚与富含 18O 的水蒸气有关。这些水蒸气的混合物在 5 月至 9 月期间在干旱的中亚地区支配了降水 δ18O。中亚干旱地区和乌拉尔南部地区降水δ18O的差异反映了季风水汽对干旱中亚地区的渗透。因此，天山中部的克桑洞和乌拉尔南部的金德林斯卡亚洞的 Speleothem δ18O 记录被选择来指示全新世期间季风水汽输送到干旱的中亚。它们的差异表明，在全新世早期、8.2 ka BP 事件和全新世晚期，当 EASM 非常弱时，显着的季风水汽被输送到干旱的中亚。结果表明，在弱东亚夏季风条件下，在全新世期间，季风水汽至少可以向西输送至中亚干旱的天山中部（~81.75°E），而不是之前假设的强东亚夏季风条件下。虽然季风水汽的量与西风水汽相比相对较少，但不可忽视，因为该来源对夏季季风季节干旱中亚地区降水及其δ18O的变化起着重要作用。