The Asian monsoon influences the lives of more than a third of the world's population, and understanding its spatial and temporal variability is fundamental to sustainable development. The complex dynamics of this climatic system are therefore of broad scientific and societal interest. In this virtual special issue (VSI), we present 19 papers dealing with the Asian monsoon since the Last Glacial Maximum (LGM, ∼21 kyr BP), with a focus on understanding variability and forcing mechanisms. Findings use recently developed quantitative reconstructions combined with numerical simulations, and present novel insights as follows: (1) analyses of comprehensive datasets of pollen, diatom, brGDGTs, oxygen and hydrogen isotopes and frequency magnetic susceptibility, as well as an innovative algorithm model for the lake energy-water balance, improve the reliability of quantitative reconstructions of Asian monsoon climate variations; (2) studies of quantitative climate parameters in central East Asia show that mean annual temperature (MAT) was ∼5 °C (or ∼ 7.9 °C using brGDGTs) lower during the LGM, ∼1.5 °C (±41% using brGDGTs) higher around the Holocene thermal optimum (HO) and mean annual precipitation (MAP) varied between 30 and 150% with marked seasonality during 8–5 ka; (3) dynamical downscaling palaeoclimatic simulations improve the accuracy of past monsoon variations, revealing strong variability in monsoon precipitation across the LGM and HO. The holistic study of Asian monsoon variations at orbital to centennial timescales in these VSI papers presents reliable observations of monsoon variability and its driving mechanisms, providing high-resolution quantitative paleoclimate reconstructions that fill existing gaps in spatial coverage, as well as offering an improved understanding, thorough numerical simulation, of coupled sea-level change and vegetation feedbacks.

中文翻译：

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过去21ka的亚洲季风变化：简介


亚洲季风影响着世界三分之一以上人口的生活，了解其时空变化对于可持续发展至关重要。因此，这一气候系统的复杂动态引起了广泛的科学和社会兴趣。在本虚拟特刊 (VSI) 中，我们发表了 19 篇有关末次盛冰期（LGM，∼21 kyr BP）以来的亚洲季风的论文，重点是了解变异性和强迫机制。研究结果利用最近开发的定量重建与数值模拟相结合，并提出了以下新颖的见解：（1）对花粉、硅藻、brGDGT、氧和氢同位素以及频率磁化率的综合数据集的分析，以及用于湖泊能量水平衡，提高亚洲季风气候变化定量重建的可靠性； (2) 对东亚中部定量气候参数的研究表明，末次盛冰期期间，年平均气温 (MAT) 降低了约 5 °C（或使用 brGDGT 时约 7.9 °C），约 1.5 °C（使用 brGDGT 时为±41%）全新世最适温度 (HO) 附近较高，年平均降水量 (MAP) 在 30% 至 150% 之间变化，在 8–5ka 期间具有明显的季节性； (3) 动态降尺度古气候模拟提高了过去季风变化的准确性，揭示了末次盛冰期和 HO 季风降水的强烈变化。 这些 VSI 论文中对亚洲季风变化在轨道到百年时间尺度上的整体研究提出了对季风变化及其驱动机制的可靠观测，提供了高分辨率定量古气候重建，填补了空间覆盖方面的现有空白，并提供了更好的理解，海平面变化和植被反馈耦合的彻底数值模拟。