| Recently, the air pollution of the Eastern China has been paid much attention.As one of the important optical parameters in the atmospheric environment, it is crucial to accurately monitor the spatio-temporal distribution of aerosol optical peoperties, and from this helping understand the formation and manage the regional air pollution. This study used the stations of CSHNET and CARE-China in the Eastern China, to analysis the distribution of Aerosol Optical Depth (AOD)and Angstrom exponent (a) and evaluate the kinds of MODIS and VIIRS AOD products in this region. The main conclusions were as follows:The aerosol optical peoperties in eastern China had obviously regional variation characteristics. From 2004 to 2013, the annual average AOD in the North background area and Beijing city were 0.20±0.02 and 0.59±0.07, and the annual average a were 0.83±0.05 and 1.13±0.08, respectively. During a decade,AOD has decreased by 0.023 and 0.057 in the North background area and Beijing city,respectively, and the radius of dominant aerosol particles were tend to be smaller.The atmosphere pollution in the Eastern China was severe. From 2013 to 2014,the annual average AOD in the North background area, Beijing city, the agriculture area in the North China, the East background area and East suburb area were 0.30±10.05, 0.63±0.10, 1.02±0.09, 1.07±0.09 and 0.85±0.08, respectively. Except for the North background area, the aerosol particles in other areas were dominated by fine particles. In the North background area, Beijing city and the agriculture area in the North China, AOD was characterized by higher values in spring and summer, and lower values in autumn and winter, but a did not change obviously around the year.On the contray, in the East background area, AOD varied little during the whole year,and the dominant aerosols were fine particles although a values were little different in the four seasons. AOD values in East suburb area were up to 1.60±0.13 during summer.The retrieved AOD of the twin MODIS carried on Terra and Aqua, included the Collection 5 and 6 of the Deep Target algorithm (DT).the Collection 6 Deep Blue algorithm (DB) and the Collection 6 Deep Target combined Deep Blue (DTDB)products, these eight kinds of AOD have been extensively used around the world.During 2004 ?2013, in the North background, more than 62% of DT matchups for C5 and C6 products were within the NASA's expected error (EE). In the Beijing city,69%?72% of C6 DB retrievals were falling within EE. From background to urban areas, the new dataset C6 DTDB both had better performance. The range of monthly absolute error was large from -0.21 to 0.28 in the background and from -0.63 to 0.48 in the urban. During a decade, the annual errors of tha all Terra and Aqua products had slightly increased by 0.0023?0.0158 and 0.0011?0.0124 per year, respectively,which implied that the two MODIS sensors had degraded slowly?NPP VIIRS which will replace Terra/Aqua MODIS in the future, had much retrieval errors in Eastern China. There were large differences between VIIRS EDR AOD and Aqua MODIS C6 DTDB, especially in winter the absolute error was in the range of -0.58?-0.39. Although EDR AOD can show the similar seasonal variation with the ground-based observations, the fitting slope of EDR AOD and ground-based observations was only 0.82?0.88, intercept was -0.002?0.04(except TH for 0.23),R was 0.73?0.88, with larger RMSE of 0.18?0.24, and the EDR product was much discrete, the larger uncertainty was mainly due to the error of aerosol model estimation. It is worth noting that although using MODIS EE to estimate EDR products have certain reference significance, the error could not be neglected. |
PDF Full Text Request