Interdecadal variations of persistent extreme heat events in eastern China under global warming

Abstract

Persistent extreme heat events (PEHEs) exert a more negative impact on society, including agriculture, plant phenology, power production and human health, compared to general EHEs. The temporal and spatial characteristics of summer PEHEs in eastern China were analysed based on a daily maximum temperature dataset from 759 stations over the period of 1961-2018. The results show the following: Persistent distributions of PEHEs show that they are characterized by an exponential decay with a drop in the decay rate. In terms of spatial distribution, there is an apparent regional difference in the duration of PEHEs. North China is dominated by multi-frequency and short-duration EHEs, while South China is the opposite. PEHEs in North China and the Huanghuai region mainly occur in June-July but mostly in July and August in South China. Strongly responding to global warming, the frequency and duration of PEHEs in North China have increased since the 1990s. However, the frequency of PEHEs in North China and the Huanghuai region has shown opposite trends in June-July since the beginning of the 21st century.Affected by the atmospheric circulations, the regional differences in PEHE frequency are also apparent. Since the beginning of the 21st century, the PEHEs in North China and the Huanghuai area have shown an increasing trend in August. The short-term PEHEs in the middle and lower reaches of the Yangtze River and South China increased rapidly in the 2000s, while long-term PEHEs increased in the 2010s. This study implies that attention should be paid to not only the frequency of EH days but also to the persistence of EHE which is a key characteristic of damaging EH.

Causes of the Unprecedented Month‐To‐Month Persistent Extreme Heat Event Over South China in Early Summer 2020: Role of Sea Surface Temperature Anomalies in the Tropical Indo‐Pacific Region

“…South China (SC), a region with one of the highest frequencies and strongest variabilities of annual mean extreme heat (EH) events in China, is generally attacked by EH events from April to October (T. Ding & Qian, 2011; K. Wei & Chen, 2009). Notably, the frequency, intensity, and duration of EH events over SC during summer have increased remarkably since the early 2000s (A. Lin et al., 2021; Luo & Lau, 2017; You et al., 2017; Zang et al., 2021; Zhu et al., 2020). The Pacific decadal oscillation is believed to be an important driver for the above interdecadal variation in frequency, which shifted from a positive phase toward a negative phase after 2003 and induced a strengthened Walker circulation and anomalous atmospheric descending motion over SC (You et al., 2017; Zhu et al., 2020).…”