中国气象科学研究院祝从文等人在最新研究中，报道了东亚夏季风年周期对华北年最大降水事件的期锁和幅锁。这一研究成果发表在2024年12月26日出版的《大气科学进展》上。

年最大降水事件（AMRE）是指一年中连续5天的最大降水量，占华北地区夏季（6 - 8月）总降雨量的15-80%，在亚季节到季节预报方面具有很大的挑战性。基于1979-2023年的资料分析，研究表明，东亚夏季风（EASM）年周期的相位和振幅模态对AMRE的年际变化有显著影响，其特征为西北太平洋850 hPa的两个正交的东南风季节型。

EASM锁相AMRE显示，北京周边地区出现了早、晚强降水事件，与6月和8月的东南风异常峰值相对应。EASM振幅锁定的AMRE在西南地区表现为极强或极小雨，相位正常。因此，AMRE在季节时间尺度上具有潜在的可预测性，因为它与东亚年周期的缓慢变化相锁。

附：英文原文

Title: Phase- and Amplitude-Locking of Annual Maximum Rainfall Events in North China with Annual Cycle of East Asian Summer Monsoon

Author: Wanyi Sun, Congwen Zhu, Boqi Liu, Yuhan Yan, Zhiqi YAN

Issue&Volume: 2024-12-26

Abstract: The annual maximum rainfall event (AMRE), is referred to as the maximum consecutive 5-day rainfall in a year, which account for 15–80% of total summer (June–August) rainfall amount in North China, showing a great challenge in subseasonal to seasonal forecast. Based on data analyses during 1979–2023, this study shows the interannual variability of AMRE is significantly influenced by the phase and amplitude mode of annual cycle of East Asian summer monsoon (EASM), featured by two orthogonal seasonal patterns of southeasterly winds at 850 hPa over the northwestern Pacific. The EASM phase-locked AMRE shows heavy rainfall events occurring extreme early and late in Beijing surrounding areas, corresponding to the peak southeasterly wind anomalies in June and August. The EASM amplitude-locked AMRE exhibits extreme heavy or light rainfall over southwest areas with normal phase. Therefore, the AMRE has a potential predictability on seasonal time scale due to its phase-locking with the slowly variation of annual cycle of EASM.

DOI: 10.1007/s00376-024-4308-2

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-4308-2viewType=HTML