An Unusual Heat Wave in North China During Midsummer, 2018

Chuhan Lu,Min Yang,Yujing Qin,Jiaxin Ye,Sitao Wang,Wenyue He,Jiaxi Cai,Qinqin Li,Jia Mao

doi:10.3389/feart.2020.00238

Chuhan Lu, Min Yang + Show 7 more

Open Access

https://doi.org/10.3389/feart.2020.00238

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Abstract

An unusual heat wave was observed at 83% of all recording stations in northeastern China, North China, and Inner Mongolia from mid-July to early August 2018. The local maximum temperatures exceeded 40℃ and brought great impacts to people’s lives and the social economy. Using NCEP/NCAR reanalysis data and station data from the China Meteorological Administration, we study the characteristics and formation of this high-temperature event. The results show that a stable, deep, local, anomalous high over northern China was the main reason for this high-temperature event. A silk-road teleconnection circulation appeared in the upstream part at the midlatitudes of Eurasia and was accompanied by clear energy dispersion of an eastward midlatitude Rossby wave, which favored the divergence of wave energy over Northeast China and led to an increase in geopotential heights and the formation and maintenance of the local anomalous high in North China. Simultaneously, the northern typhoons “Ampil” and “Jongdari” had connections with the local anomalous high, generated obvious secondary meridional circulations, and amplified the downdrafts in the region of the high and the maintenance and intensification of high temperatures. Further analysis revealed that the sea surface temperature anomalies (SSTAs) in the middle of the North Atlantic Ocean in earlier periods would initiate negative vorticity sources on the northwestern side in the high-level troposphere and have a great impact on the generation and maintenance of the high-level silk-road teleconnection.

Highlights

The fifth report of the Intergovernmental Panel on Climate Change (IPCC) pointed out that global warming has been obvious over the past 100 years (Pachauri et al, 2014)
Based on NCEP/NCAR reanalysis and daily data from the National Meteorological Information Center of the China Meteorological Administration, we discussed the mechanisms leading to the 2018 mid-summer heat wave in North China
We analyzed the generation of the local anomalous high in North China through Rossby wave dispersion and by oceanic thermodynamic forcing

Summary

INTRODUCTION

The fifth report of the Intergovernmental Panel on Climate Change (IPCC) pointed out that global warming has been obvious over the past 100 years (Pachauri et al, 2014) With this background, the substantial increasing mean temperature lead to high risks of extreme high-temperature events (Stocker et al, 2013). Sun et al (2011) indicated that the persistent extremely high temperatures in North China in the period from midJuly to late August are related to positive geopotential height anomalies in the mid/high levels of the troposphere. Wakabayashi and Kawamura (2004) noted that the western Asia-Japan teleconnection is an important teleconnection that affects summertime temperatures in Japan External forcing, such as the snow cover on the Tibetan Plateau (Wu et al, 2012) and El Nino events (Niu and Guo, 1998), are related to summertime heat waves in North China. When the station daily maximum temperatures exceed 32◦C and last for 3 days or more, these conditions are defined as a heat wave event (Qian and Wang, 2017), which can be discussed in the context of a persistent extreme high-temperature process

Methodology

CONCLUSION AND DISCUSSION

Findings

DATA AVAILABILITY STATEMENT