Opposite trends of cold surges over South China Sea and Philippines Sea and their different impacts on PM2.5 in eastern China

Shiyue Zhang; Gang Zeng; Xiaoye Yang; Tijian Wang

doi:10.1016/j.scitotenv.2023.168454

Opposite trends of cold surges over South China Sea and Philippines Sea and their different impacts on PM_2.5 in eastern China

Sci Total Environ. 2024 Jan 15:908:168454. doi: 10.1016/j.scitotenv.2023.168454. Epub 2023 Nov 11.

Authors

Shiyue Zhang¹, Gang Zeng², Xiaoye Yang¹, Tijian Wang³

Affiliations

¹ Key Laboratory of Meteorological Disaster, Ministry of Education, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Nanjing University of Information Science and Technology, Nanjing 210044, China.
² Key Laboratory of Meteorological Disaster, Ministry of Education, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Nanjing University of Information Science and Technology, Nanjing 210044, China. Electronic address: zenggang@nuist.edu.cn.
³ School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China.

PMID: 37956853
DOI: 10.1016/j.scitotenv.2023.168454

Abstract

The variations in cold surge (CS) path can cause significant impacts on air pollution in the area it passes through. This study investigates impacts of CSs over South China Sea (CS_SCS) and Philippine Sea (CS_PHS) on PM_2.5 concentrations in eastern China (PC_EC) and their underlying mechanisms from 1979 to 2021. It was revealed that the CS_SCS is accompanied by the continental high-pressure over East Asia and shows an upward trend. CS_PHS is mainly affected by both the continental high-pressure over East Asia and the East Asian Trough over the Sea of Japan, showing a significant downward trend. Such difference in circulation anomalies is related to the different paths of the two types of CSs. Both observation and simulations indicate that more (less) Ural blocking in winter would lead to the cold air originating from the regions over Lake Baikal (Caspian Sea) to invade southward (eastward) along the northern (northwestern) path, resulting in more frequent CS_SCS (CS_PHS) and increased (decreased) winter averaged PC_EC due to the anticyclonic (cyclonic) anomalies over eastern China. Such variations in winter averaged PC_EC masked the synoptic signals that PC_EC would decrease (increase) during CS_SCS (CS_PHS) outbreaks. Therefore, the increased frequency of atmospheric blocking over Ural Mountains in recent years has still played a worsening role in the intensification of PC_EC.

Keywords: Cold surge; Numerical simulation; PM(2.5) concentrations; Ural blocking.