Abstract. Eastern China (EC), located in the downstream region of the Tibetan Plateau (TP),
is a large area with frequent haze pollution. In addition to air pollutant
emissions, meteorological conditions are a key inducement for air pollution
episodes. Based on the study of the Great Smog of London in 1952 and haze
pollution in EC over recent decades, it is found that the abnormal “warm
cover” (air–temperature anomalies) in the middle troposphere, as a
precursory strong signal, could be connected to severe air pollution
events. The convection and vertical diffusion in the atmospheric boundary
layer (ABL) were suppressed by a relatively stable structure of warm cover
in the middle troposphere leading to ABL height decreases, which were
favorable for the accumulation of air pollutants in the ambient
atmosphere. The anomalous structure of the troposphere's warm cover not
only exist in heavy haze pollution on the daily scale, but also provide
seasonal, interannual and interdecadal strong signals for frequently
occurring regional haze pollution. It is revealed that a close relationship
existed between interannual variations of the TP's heat source and the warm
cover strong signal in the middle troposphere over EC. The warming TP could
lead to anomalous warm cover in the middle troposphere from the
plateau to the downstream EC region and even the entire East Asian region, thus causing frequent winter haze pollution in EC region.
Supplementary material to "Warm Cover – Precursory Strong Signals hidden in the Middle
Troposphere for Haze Pollution"
