The present study investigates meteorological conditions for the day-to-day changes of particulate matter （PM） concentration in Beijing city during the period 2008-2015. The local relationship of PM concentration to...The present study investigates meteorological conditions for the day-to-day changes of particulate matter （PM） concentration in Beijing city during the period 2008-2015. The local relationship of PM concentration to surface air temperature, pressure, wind speed, and relative humidity displays seasonal changes and year-to-year variations. The average correlation coefficient with PMI0 in spring, summer, fall, and winter is 0.45, 0.40, 0.38, and 0.30 for air tem- perature; -0.45, -0.05, -0.40, and -0.45 for pressure; 0.13, 0.04, 0.53, and 0.50 for relative humidity; and -0.18, -0.11, -0.45, and -0.33 for wind speed. A higher correlation with wind speed is obtained when wind speed leads by halfa day. The heavily polluted and clean days, which are defined as the top and bottom 10% of the PM values, show obvious differences in the regional distribution of air temperature, pressure, and wind. Polluted days correspond to higher air temperature in all the four seasons, lower sea level pressure and anomalous southerly winds to the south and east of Beijing in spring, fall, and winter, and a northwest-southeast contrast in the pressure anomaly and anom- alous southerly winds in summer. Higher relative humidity is observed on polluted days in fall and winter. The pol- luted days are preceded by an anomalous cyclone moving from the northwest, accompanied by lower pressure and higher air temperature, in all four seasons. This feature indicates the impacts of moving weather systems on local meteorological conditions for day-to-day air quality changes in Beijing.展开更多
基金Supported by the National Natural Science Foundation of China(41475081,41530425,41425019,and 41661144016)State Oceanic Administration Public Science and Technology Research Funds Projects of Ocean(201505013)
文摘The present study investigates meteorological conditions for the day-to-day changes of particulate matter （PM） concentration in Beijing city during the period 2008-2015. The local relationship of PM concentration to surface air temperature, pressure, wind speed, and relative humidity displays seasonal changes and year-to-year variations. The average correlation coefficient with PMI0 in spring, summer, fall, and winter is 0.45, 0.40, 0.38, and 0.30 for air tem- perature; -0.45, -0.05, -0.40, and -0.45 for pressure; 0.13, 0.04, 0.53, and 0.50 for relative humidity; and -0.18, -0.11, -0.45, and -0.33 for wind speed. A higher correlation with wind speed is obtained when wind speed leads by halfa day. The heavily polluted and clean days, which are defined as the top and bottom 10% of the PM values, show obvious differences in the regional distribution of air temperature, pressure, and wind. Polluted days correspond to higher air temperature in all the four seasons, lower sea level pressure and anomalous southerly winds to the south and east of Beijing in spring, fall, and winter, and a northwest-southeast contrast in the pressure anomaly and anom- alous southerly winds in summer. Higher relative humidity is observed on polluted days in fall and winter. The pol- luted days are preceded by an anomalous cyclone moving from the northwest, accompanied by lower pressure and higher air temperature, in all four seasons. This feature indicates the impacts of moving weather systems on local meteorological conditions for day-to-day air quality changes in Beijing.
