2025年南海夏季风对华南前汛期降水的影响

Impact of the 2025 South China Sea Summer Monsoon on Precipitation during the Pre-Flood Season in South China

摘要: 为分析2025年南海夏季风爆发特征及其对华南前汛期降水的影响，利用ERA5再分析资料和地面降水观测数据，对低层环流、对流活动及降水变化进行诊断分析，重点揭示夏季风爆发前后环流结构及降水响应特征。结果表明，2025年南海夏季风于5月第6候爆发，低层西南气流显著增强，华南前汛期降水在爆发后过程性增强，但整体较常年偏少。研究结果可为前汛期降水监测、成因分析及业务预报提供参考依据。

Abstract: To analyze the onset characteristics of the 2025 South China Sea Summer Monsoon (SCSSM) and its impacts on precipitation during the pre-flood season in South China, ERA5 reanalysis data and surface precipitation observations were utilized to diagnostically analyze the low-level atmospheric circulation, convective activity, and precipitation variations. This study primarily focuses on revealing the circulation structure and precipitation response characteristics before and after the monsoon onset. The results indicate that the 2025 SCSSM onset occurred in the 6th pentad of May, accompanied by a significant intensification of the low-level southwesterly flow. Following the onset, precipitation during the pre-flood season in South China exhibited episodic enhancements; however, the overall rainfall was below the climatological normal. The findings of this study can provide a scientific reference for precipitation monitoring, mechanistic analysis, and operational forecasting during the pre-flood season.