The upper tropospheric-lower stratospheric ozone drives summer precipitation and wildfire changes in West Siberia

Fei Xie; Yan Xia; Wenshou Tian; Martyn P Chipperfield; Wuhu Feng; Ke Gui; Yingli Niu; Na Liu; Yuanyuan Han

doi:10.1016/j.scib.2024.11.016

The upper tropospheric-lower stratospheric ozone drives summer precipitation and wildfire changes in West Siberia

Sci Bull (Beijing). 2024 Nov 13:S2095-9273(24)00814-4. doi: 10.1016/j.scib.2024.11.016. Online ahead of print.

Authors

Fei Xie¹, Yan Xia², Wenshou Tian³, Martyn P Chipperfield⁴, Wuhu Feng⁵, Ke Gui⁶, Yingli Niu⁷, Na Liu⁷, Yuanyuan Han⁸

Affiliations

¹ School of Systems Science, Beijing Normal University, Beijing 100875, China. Electronic address: xiefei@bnu.edu.cn.
² School of Systems Science, Beijing Normal University, Beijing 100875, China. Electronic address: xiayan@bnu.edu.cn.
³ Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
⁴ School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK; National Centre for Earth Observation, University of Leeds, Leeds LS2 9JT, UK.
⁵ School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK; National Centre for Atmospheric Science, University of Leeds, Leeds LS2 9PH, UK.
⁶ State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
⁷ Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
⁸ Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an 710048, China.

PMID: 39580242
DOI: 10.1016/j.scib.2024.11.016

Abstract

Siberian wildfires are pivotal in determining the carbon cycle and climate dynamics, exerting a profound impact on the ecosystems of the entire Arctic region. Over the past few decades, variations in summer precipitation in West Siberia have significantly influenced wildfire activity. This study analyzed precipitation trends in West Siberia from 1982 to 2021 using observations and transient simulations, uncovering a strong correlation between precipitation variability and ozone concentrations in the upper troposphere-lower stratosphere (UTLS). Heightened UTLS ozone levels warm the upper atmosphere over West Siberia during summer. This warming modifies the regional polar jet stream, intensifying its southern branch and weakening the northern one, leading to a southward shift in the jet stream. Consequently, cyclonic circulation anomalies emerge in the upper troposphere, characterized by a barotropic structure with unusual upward movements around 60°N. This upward motion triggers corresponding anomalies in zonal winds in the lower troposphere, fostering a low-pressure system at the surface. This atmospheric shift results in an influx of warm, moist air from the south and cold, dry air from the north into Siberia, enhancing cloud formation and precipitation. Notably, our analysis suggests that the rise in summer precipitation in West Siberia between 1993 and 2010 is linked to increased UTLS ozone concentrations during this period. Conversely, the decline in UTLS ozone since 2010 may increase the risk of wildfires by suppressing precipitation. Our findings underscore the pivotal role of stratospheric chemistry in shaping the regional climate and wildfire behavior.

Keywords: Ozone; Precipitation; Radiative effect; Siberia; Upper troposphere-lower stratosphere.