Extreme heatwave over Eastern China in summer 2022: the role of three oceans and local soil moisture feedback

Abstract

Eastern China experienced persistent regional extreme heatwaves in the summer of 2022, with disparate spatial features and formation mechanisms in different months. We quantitatively assessed the relative contributions of three oceans, i.e., tropical Indian Ocean and Pacific and North Atlantic, and the local soil moisture–temperature feedback using linear regression. The results showed that the monthly mean atmospheric circulation anomalies failed to explain the extreme heatwave in June 2022. The combined contribution of the tropical Indo-Pacific and North Atlantic Sea surface temperature anomalies (SSTAs), together with the local soil moisture–temperature feedback, explaining approximately 10% of the temperature anomalies. In July, the tropical Indo-Pacific SSTAs promoted anomalous atmospheric circulation and extreme heat via meridional circulation originating in the Maritime Continent, accounting for approximately 10% of the temperature anomalies, with North Atlantic SSTAs contributing the same percentage by a mid-latitude steady Rossby wave. Local soil moisture–temperature feedback accounted for 42% of the anomalies. The tropical Indo-Pacific SSTAs produced a strong western North Pacific anticyclone in August, but their direct contribution to the temperature anomalies was negligible. The North Atlantic SSTAs contributed 9% of the total via the mid-latitude steady Rossby wave. Local soil moisture–temperature feedback contributed 66%, suggesting that the July heatwave and drought exerted a significant impact on the subsequent August extreme heatwave. Global warming has greatly facilitated extreme heatwaves, accounting for about 30%~40% of these events in summer 2022. These results also suggest that the climatic effects of tropical Indo-Pacific and North Atlantic SSTAs on Eastern China are evident in the month-to-month variation in summer. Our results thus contribute to the understanding and prediction of extreme heatwaves in Eastern China.

Possible influences of spring Barents Sea ice shrinking on Chinese heat wave events

“…Coloured omega arrows represent results of regression analysis were at 90% confidence level [Colour figure can be viewed at wileyonlinelibrary.com] and ENSO (Arblaster & Alexander, 2012;Luo & Lau, 2019), can also influence the interannual variations in heat waves and temperature over China. In addition, local soil moisture and temperature feedbacks deserve attention in future research (Jiang et al, 2023). The tropical Indo-Pacific SST anomaly mainly leads to the convection anomaly in the oceanic continental area through the zonal Walker circulation anomaly and further promotes the development of subsidence and high-temperature anomaly in south China (Deng et al, 2020).…”

An energetics tale of the 2022 mega-heatwave over central-eastern China

“…Given that more deadly heatwaves are projected in the future, quantifying the casual factors of mega-heatwave and further disentangling the origin of the uncertainties of heatwave prediction can provide impactbased decision-making support for disaster mitigation and prevention [11][12][13][14] . While several studies attributed the extremely hot summer in 2022 to extra-tropical atmospheric circulation, tropical sea surface temperature, and local soil moisturetemperature feedback, the latter being a comprehensive quantitative attribution of the multiple dynamical and radiative drivers on the occurrence of this mega-heatwave is absent [15][16][17][18][19][20] . In fact, this attribution gap exists in almost the entire research community for climate and weather extremes.…”

Increased Population Exposure to Heat and Wet Extremes Moving From Chinese to Global 1.5 or 2.0°C Warming

“…Moreover, in 2022, the deaths of more than 15,000 people in Europe were associated with unusual heat extremes, and the temperature in the United Kingdom exceeded 40°C for the first time (WMO, 2023). In 2022, long‐lasting heat extremes in China since records began in 1961 were exceeded for 79 days, where over 5 million km 2 were affected (Jiang et al., 2023; Liu et al., 2023; Ma & Yuan, 2023; WMO, 2023).…”

“…The possible mechanisms associated with these heat extremes have been investigated to better understand their causes and to adapt to the possible risk of future extremes (Cui et al., 2023; Jiang et al., 2023; Roethlisberger & Papritz, 2023; Ventura et al., 2023; Wu, Luo, et al., 2023; Zhang & Boosa, 2023; Zhang, Zhou, et al., 2023). Heat extremes are usually quantified based on the air surface temperature and temperature anomalies are mainly determined by the following physical processes: temperature advection through large‐scale atmospheric circulation, adiabatic compression and warming, and diabatic heating of surface air (Roethlisberger & Papritz, 2023; Tamarin‐Brodsky et al., 2020).…”

“…Heat extremes are usually quantified based on the air surface temperature and temperature anomalies are mainly determined by the following physical processes: temperature advection through large‐scale atmospheric circulation, adiabatic compression and warming, and diabatic heating of surface air (Roethlisberger & Papritz, 2023; Tamarin‐Brodsky et al., 2020). The mechanisms associated with heat extremes are complex and the dominant factors can vary among different regions during different periods (Jiang et al., 2023). The strong high‐pressure system could explain half of the heat extremes in North America, which increased faster than the mean temperature due to land surface and atmosphere interactions (Zhang, Zhou, et al., 2023).…”