Influence of mixed air pollution on surface micro-meteorological characteristics in autumn and winter in Nanjing area

Abstract

Abstract: This work used the Multi-element observation data from the Station for Observing Regional Processes of the Earth System (SORPES) from November 27 to December 3, 2018. It quantitatively analyzed the influence of mixed air pollution conditions on the surface micrometeorological elements and energy balance characteristics under the combined effects of long-distance sand and dust and local emission pollution. On this basis, the response characteristics of surface meteorological elements and energy distribution under different pollution conditions in autumn and winter in Nanjing are compared by synthetic analysis. The results showed that the daytime temperature on polluted days was about 1°C lower than that on clean days, and the night temperature was about 2°C higher. Both downward/upward shortwave radiation flux decreased on polluted days, and the long-wave radiation flux at night increased. On clean days, the net radiation budget during the day was 45.6% higher than that of polluted days and the surface sensible heat flux was 75.5% higher than that of polluted days. The average Bowen ratio at night on polluted days was higher than that on clean days, indicating that the nighttime sensible heat exchange was stronger. The results help to deeply understand the influence process and mechanism of air pollution from different sources and different properties on surface energy balance and local meteorological elements in the urban agglomerations of the Yangtze River Delta, and the results also provide a verification basis for the interaction between air pollution and meteorological conditions, air quality prediction and corresponding countermeasures.