ESTIMATING HOURLY PM<sub>2.5</sub> CONCENTRATIONS FROM HIMAWARI-8 AOD OVER HUBEI PROVINCE

oleh: J. Chen, X. Huang

Format: Article
Diterbitkan: Copernicus Publications 2018-09-01

Deskripsi

Satellite remote sensing can effectively estimate the particulate matter on a large scale. Polar-orbiting satellites have limited frequency of observations, which cannot help us understand PM<sub>2.5</sub> evolution. The observation frequency of Himawari-8, a geostationary meteorological satellite, increases to at least once every 10&thinsp;min. Besides, this satellite can provide the hourly aerosol optical depth (AOD). PM<sub>2.5</sub> concentration is closely associated with changes in wind speed. The air quality changes with the variations of wind direction and speed. In Hubei Province, the daily average wind speed varies greatly, while the wind significantly impacts the PM<sub>2.5</sub> diffusion. In the present study, a mixed effect regression model is developed which predicts ground-level hourly PM<sub>2.5</sub> concentrations in Hubei province and analyzes the hourly time variation trend and spatial distribution characteristics of the near ground PM<sub>2.5</sub> concentrations using the annual Himawar-8 Level 2 aerosol product in 2016. The estimated hourly PM<sub>2.5</sub> concentrations are consistent well with the surface PM<sub>2.5</sub> measurements with high <i>R</i><sup>2</sup> (0.74) and low RMSE (20.5&thinsp;&mu;g∙m<sup>&minus;3</sup>). The average estimated PM<sub>2.5</sub> in Hubei province during the study is about 46.1&thinsp;&mu;g∙m<sup>&minus;3</sup>. A clear regional distribution is shown in the spatial distribution of PM<sub>2.5</sub> concentrations, and the PM<sub>2.5</sub> concentrations in the central and eastern regions of Hubei Province is significant higher than that of the western region; from the perspective of time change, the pollution peak appears at 15&thinsp;o'clock in the local time, the average concentration of PM<sub>2.5</sub> reaches 50.1&thinsp;&plusmn;&thinsp;21.8&thinsp;&mu;g∙m<sup>&minus;3</sup>; the pollution reaches the lightest at 9&thinsp;o'clock a.m., and the average PM<sub>2.5</sub> concentrations is 41.7&thinsp;&plusmn;&thinsp;17.5&thinsp;&mu;g∙m<sup>&minus;3</sup>. These results are conducive to assessing surface PM<sub>2.5</sub> concentrations and monitoring regional air quality.