气候变化领域集成服务门户

This study reviews spatial and temporal variability of aerosol optical depth (AOD) at 550nm, obtained with Moderate Resolution Imaging Spectroradiometer (MODIS) (Terra) Collection 6.1 aerosol products with use of combined Dark Target and Deep Blue algorithm. Data was analyzed for 18-year period from 2000 to 2017 over the territory of the whole continental China, covering the largest cities as well as various ecological and geographical regions. Spatial distribution of AOD has distinct geographical differences with gradual decrease from the east to the west of the country. The lowest values (up to 0.25) of annual mean AOD at 550nm occur in sparsely populated areas on the Tibetan Plateau and in the north forest ecosystems in the north-eastern part of China. Areas of desert and semidesert landscapes of Northwest China are characterized by high concentrations of naturally occurring aerosols with moderate values of AOD (0.4-0.7). The most populous regions (Pearl River Delta, Yangtze River Delta, North China Plain, and Sichuan Basin) with the highest density of agricultural and industrial activity are characterized with maximum values of AOD (over 0.7). Seasonal variation of aerosols in the most regions of China has maximum AODs in spring or summer and minimum in autumn or winter. angstrom ngstrom exponent (AE), being 0.31-1.7 for the most part of China, was used to detect the size of aerosol particles, with the lowest values (0.31-0.84) in desert north and north-west regions of the country, and the higher values in the south (1.3-1.7). Comparison of results, obtained with MODIS Terra and AERONET (Aerosol Robotic Network) at 550nm, demonstrate a high interrelation (r=0.8949), where 68.3% fall within the range of expected errors, set by MODIS over the land (+/- 0.05 +/- 0.15xAOD). The conducted Pearson's correlation analysis between various cities of the country showed that cities in one region with shortest distances from one another demonstrated higher correlations, suggesting distinct regional dependence in aerosols distribution.