Weather pattern conducive to the extreme summer heat in North China and driven by atmospheric teleconnections

Abstract

Extreme summer heat can have severe socioeconomic impacts and has occurred frequently in North China in recent years, most notably in June–July 2023, when North China experienced the most widespread, persistent, and high-intensity extreme heat on record. Here, typical weather patterns covering North China and its surrounding areas were classified into seven types based on the Cost733class package, and the weather pattern type 4 (T4), characterized by the strengthened ridge and anticyclone anomaly in northeastern China, was found as the most favorable for the occurrence of extreme summer heat in North China (NCSH). Diagnostic and wave activity flux analyses indicate that the Eurasian teleconnection (EAT) pattern from the atmosphere and the Victoria mode (VM) from the ocean are the top two dominant climate drivers of the T4 weather pattern. The empirical models constructed based on the EAT and the VM can effectively simulate the number of days of the T4 weather pattern and the NCSH, respectively. Our results suggest that, with the help of the seasonal forecast from climate models, the EAT and the VM can be used to predict the number of days of the T4 weather pattern and the NCSH for the coming summer, enabling us to protect human health and reduce its socioeconomic impacts through proactive measures in advance.

Keywords

• North China extreme summer heat (NCSH)
• classification of weather patterns
• Eurasian teleconnection (EAT) pattern
• Victoria mode (VM)
• empirical model