Decadal changes of connections among late-spring snow cover in West Siberia, summer Eurasia teleconnection and O3-related meteorology in North China

Abstract

Severe surface ozone (O3) pollution frequently occurred in North China and obviously damages human health and ecosystems. The meteorological conditions effectively modulate the variations in O3 pollution. In this study, the interannual relationship between O3-related meteorology and late-spring snow cover in West Siberia was explored, and the reasons for its decadal change were also physically explained. Before mid-1990s, less snow cover could enhance net heat flux and stimulate positive phase of the Eurasian (EU) teleconnection in summer. The positive EU pattern resulted in hot, dry air and intense solar radiation in North China, which could enhance the natural emissions of O3 precursors and photochemical reactions in the atmosphere closely related to high O3 concentrations. However, after the mid-1990s, the southern edge of the dense snow cover area in West Siberia shifted northward by approximately 2g in latitude and accompanied radiation and heat flux also retreated toward the polar region. The connections among snow anomalies, EU pattern and surface O3 became insignificant and thus influenced the stability of the predictability.