小冰期以来东亚夏季风核心区与边缘区水热组合对比研究

由于温度和降水组合的异常变化而引发热浪与干旱等并发对人类社会和生态系统的危害性成倍增加，这种水热组合的变化规律和影响机制也是国际古气候研究的学术前沿。已有气候重建研究表明小冰期回暖以来东亚季风核心区与边缘区水热组合变化存在争议，加之气候重建与模拟的不匹配现象进一步限制了研究重建水热组合的影响过程。针对上述问题，本项目拟选择水热组合关系反向的两个典型地区长江中下游和黄河上游为研究对象，基于树轮宽度和氧同位素等记录进行气候集成研究，获取东亚季风核心区与边缘区温度和降水组合的多尺度变化证据，在此基础上，采用最新的粒子滤波数据同化技术，同化模拟小冰期以来东亚季风区气候变化过程，阐明小冰期回暖以来东亚夏季风水热组合变化所对应的大气环流和水汽输送特征，揭示工业革命前自然因素主导气候变化的背景下影响季风区夏季温度和降水组合变化的物理机制，为理解当前复合型极端气候事件发生机理及其未来变化趋势提供科学参考。

Concurrent droughts and heatwaves caused by the combined temperature-precipitation variations often have double impacts on humans and ecosystems in East Asia. The influence mechanism of this hydrothermal combination is also an academic frontier in paleoclimate research. Previous studies of climate reconstructions suggested that the hydrothermal combination of the core and marginal areas of the East Asian monsoon since the Little Ice Age is still controversial, and the mismatch between reconstruction and simulation further limits the research process of the impact of the reconstructed hydrothermal combination. This project intends to select two typical regions with the reverse relationship of hydrothermal combination in the middle and lower reaches of the Yangtze River and the upper Yellow River as the research objects, and to obtain the variations of the temperature and precipitation combination in core and marginal areas of the East Asian monsoon over various timescales, based on the integration of tree ring width and oxygen isotope records. On this basis, the climate variation of the East Asian monsoon region since the Little Ice Age is obtained using the particle filter method as a data assimilation approach, to quantitatively clarify the atmospheric circulation and water vapor transport, corresponding to the spatiotemporal evolution of the hydrothermal combination in East Asian summer monsoon since the Little Ice Age, and explore the variation mechanism of summer temperature-precipitation combination in the monsoon region under the background of climate variation dominated by natural factors before the Industrial Revolution. This provides scientific reference to understand the occurrence mechanism and its future trends of current composite extreme climate event.