青藏高原中部地区地处中纬度西风带和亚洲季风影响的过渡地带，环流系统和水汽来源复杂，在高原湖-气相互作用研究中，很少有人关注湖泊效应影响极端降水对背景环流的依赖关系，为深入理解湖泊影响极端降水的作用机制，本文对湖泊密集分布的青藏高原中部秋季区域性极端降水事件的主控天气型进行客观分类，进而分析不同主控天气型下湖泊效应的特征和差异。基于 1979-2018 年间的CMFD降水数据和ERA5再分析资料，首先识别出秋季青藏高原中部的1358个区域性极端降水事件，并发现其对高原中部大部分地区秋季总降水量的贡献超过 40%，区域性极端降水量的大值中心主要集中在纳木错流域及以北小湖泊群附近地区，这也是区域性极端降水发生时极端降水发生概率高的地区。然后利用谱聚类方法对区域性极端降水事件发生时青藏高原中部地区上空大气环流进行分析，识别出区域性极端降水的三类主控天气型：弱辐合气流引发的南部山区降水（P1型）、季风西南气流控制下的东北部下游降水（P2型）以及西风槽前西南气流影响下的湖泊邻近区降水（P3型），它们分别贡献了秋季区域性极端降水事件发生总数的48. 8%、42. 3%和8. 8%，其中P1和P2型集中发生在9月，P3型集中发生在10月。通过分析不同主控天气型下大尺度环流场及其异常的高、低层配置进而解释了P1、P2和P3三类主控天气型导致区域性极端降水发生的物理机制。进而通过多个例敏感性试验揭示了不同主控天气型下青藏高原中部湖泊群对区域性极端降水事件影响的相对重要性。在P1、P2和P3天气型下湖泊群可以分别导致青藏高原中部平均降水量减少2. 37%、增加12. 11%和增加138. 37%，说明P3型下的湖泊效应在三类天气型中最为显著。进一步的机制分析表明，湖泊增暖、增湿效应引起的湖泊及周边地区低层大气不稳定性和水汽辐合的增强在P3天气型下区域性极端降水的形成中起着重要作用。本研究明确了青藏高原中部秋季区域性极端降水的主控天气型并揭示出不同主控天气型下湖泊效应对区域性极端降水影响的相对重要性，为进一步提高区域性极端降水的预测水平提供了必要的参考依据。

The central Qinghai-Xizang Plateau is located in the transition zone between the mid-latitude wester‐ lies and the Asian monsoon，with complex circulation systems and water vapor sources. In the studies of lake-at‐mosphere interaction in the Qinghai-Xizang Plateau，little attention has been paid to the dependence of lake effect on background circulation to understand the mechanism of lake affecting extreme precipitation. To further understand the mechanism of lake influence on extreme precipitation，this study objectively classifies the dominant synoptic patterns responsible for the regional extreme precipitation events in autumn over the central QinghaiXizang Plateau with lakes densely distributed to analyze the characteristics and differences of lake effects under different dominant synoptic patterns. Based on the CMFD precipitation data and ERA5 reanalysis data during 1979 to 2018，1358 regional extreme precipitation events were detected in autumn over the central QinghaiXizang Plateau，and it was found that the regional extreme precipitation events contributed more than 40% of the total autumn precipitation in most parts of the central Qinghai-Xizang Plateau with the large centers of regional extreme precipitation amount mainly concentrated in the Nam co basin and the small lakes in the north，that is al‐ so the region with high occurrence probability of extreme precipitation when regional extreme precipitation event occurs. Then，the spectral clustering method was used to analyze the atmospheric circulation over the central Qinghai-Xizang Plateau during the regional extreme precipitation events and identified three dominant synoptic pat‐ terns responsible for the regional extreme precipitation events in autumn over the central Qinghai-Xizang Plateau：precipitation in the southern mountainous areas caused by weak convergence airflow（P1 type），precipitation in the northeast downstream under the control of monsoonal southwest airflow（P2 type），and precipitation near lakes under the influence of southwest airflow in front of the westerly trough（P3 type）. They lead to 48. 8%，42. 3% and 8. 8% of the total occurrences of regional extreme precipitation events in autumn，respectively. P1 and P2 types mainly occur in September，and P3 type mainly occurs in October. The physical mechanism of the regional extreme precipitation occurrences is explained by analyzing the high and low level configuration of large-scale circulation fields and their anomalies under different synoptic patterns. Furthermore，multiple sensitivity experiments were conducted to reveal the relative importance of the influence of lake clusters in the central Qinghai-Xizang Plateau on regional extreme precipitation events under different synoptic patterns，and found that the lake clusters can lead to the precipitation amount averaged over the central Qinghai-Xizang Plateau reduced by 2. 37%，increased by 12. 11% and increased by 138. 37% under the P1，P2 and P3 types，respectively. The lake effect under the P3 type is the most significant among the three synoptic types，making it a synoptic pattern prone to lake effect. Further mechanistic analysis shows that the enhancement of low-level instability and water vapor convergence over the lake and surroundings areas induced by the heating and moistening effect of lake play an important role in the formation of the regional extreme precipitation under the synoptic pattern P3. This research has identified the dominant synoptic patterns responsible for the regional extreme precipitation events over the central Qinghai-Xizang Plateau in autumn and revealed the relative importance of lake effects on regional extreme precipitation under different dominant synoptic patterns，providing necessary reference for further improving the prediction level of regional extreme precipitation.