Understanding the climatic evolution in Central Asia (CA) and its drivers is crucial for informed decision-making and predicting global changes due to its significant contribution as a global dust source. Unfortunately, our current understanding of the pre-Holocene precipitation patterns in CA is lacking due to the limited availability of reliable proxy indicators, and our knowledge of future precipitation projections in the region, based on paleoclimatic dynamics, is also quite limited. In this study, we analyzed variations in carbonate and dolomite contents of a loess section in the Ili Basin, northern CA, to reveal precipitation changes during the last glacial period. The results showed that changes in carbonate minerals were mainly influenced by the source material supply, driven by reduced precipitation and eluviation during glacial period. We thereby established a precipitation index by removing the influence of provenance signals from the dolomite records. The index indicated lower precipitation during mid-marine isotope stage (MIS) 3 compared to MIS2, likely due to meridional shifts and intensity changes of the westerlies caused by changes in precession and obliquity, with precession playing a major role. Through the comparison of the precipitation index with the δ18O records of the Greenland ice core on a millennial timescale, it was observed that the precipitation in northern CA exhibited a positive correlation with the North Atlantic Oscillation (NAO) mode due to migration of the westerlies. By leveraging our understanding of orbital- and millennial-scale precipitation patterns, we utilized the random forest (RF) regression model and the autoregressive integrated moving average model to forecast precipitation changes for the upcoming 5000–10,000 years. The results indicated a variable pattern marked by a general upward trend, suggesting the possibility of favorable development of agricultural-based economies in the Ili River Valley. People should realize that some integrated measures are designed to improve resilience of agricultural sector in the region and enhance its capacity to adapt to challenges posed by climate change. However, more extensive research is necessary to verify these results through thorough examination and comparisons of loess sections in our research location.

中文翻译：

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中亚北部伊犁盆地末次冰期降水变化，根据黄土白云岩的记录推断


由于中亚 （CA） 作为全球尘埃源的重大贡献，了解中亚 （CA） 的气候演变及其驱动因素对于做出明智的决策和预测全球变化至关重要。不幸的是，由于可靠的替代指标有限，我们目前对 CA 全新世前降水模式的理解不足，而且我们基于古气候动力学对该地区未来降水预测的了解也相当有限。在这项研究中，我们分析了 CA 北部伊犁盆地黄土剖面碳酸盐和白云石含量的变化，以揭示末次冰期的降水变化。结果表明：碳酸盐矿物的变化主要受烃源物质供应的影响，而冰期降水和洗脱减少是碳酸盐矿物变化的驱动力。因此，我们通过消除白云石记录中物源信号的影响来建立沉淀指数。该指数表明，与 MIS2 相比，中海洋同位素阶段 （MIS） 3 的降水较低，这可能是由于岁差和倾角变化引起的经向偏移和西风强度变化，其中岁差起主要作用。通过降水指数与格陵兰冰芯在千年时间尺度上的δ18O记录的比较，观察到CA北部的降水与西风带迁移引起的北大西洋涛动（NAO）模式呈正相关。通过利用我们对轨道和千年尺度降水模式的理解，我们利用随机森林 （RF） 回归模型和自回归集成移动平均模型来预测未来 5000-10,000 年的降水变化。 结果表明，伊犁河流域呈现以总体上升趋势为特征的可变模式，表明伊犁河流域农业经济有可能得到良好发展。人们应该认识到，一些综合措施旨在提高该地区农业部门的复原力，并增强其适应气候变化带来的挑战的能力。然而，需要更广泛的研究，通过对我们研究地点的黄土切片进行彻底检查和比较来验证这些结果。