Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Abstract

East China is among the fastest developing area in Asia, where atmospheric aerosol loading is high due to heavy urban and industrial emission. The Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 aerosol products (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) were used to study aerosol spatial and temporal distributions, as well as their variations with local meteorological conditions over East China. By combining Aerosol Optical Depth (AOD) and aerosol Fine Mode Fraction (FMF), we found that the urban/industrial aerosol and soil dust are possibly two dominant species over northern part, whereas continental and marine aerosols possibly dominate the southern part of East China. Both annual mean AOD and area with high AOD increased from 2000 to 2007, with the largest increase seen in Yangtze River Delta region (YRD). In summer, AOD in East China reached the maximum of about 0.8 in YRD, dominated by fine mode particles. The minimum AOD occurred in winter with mostly coarse mode particles. Local aerosol properties were analyzed in three typical zones: the northern dry zone (I), the central urban/industrial zone (II) and the southern natural background zone (III). Monthly mean AODs in zone I and II were above 0.5 throughout the entire year, with the maximum AOD in June. High FMFs in this period indicated heavy urban and industrial pollution. Monthly mean AODs and FMFs in zone III reached maximum of 0.51 in April and September (up to 90.7%) respectively. High AOD in spring in zone III appears mostly due to the long-range dust transport from the North.

Investigation of the Optical Properties of Aerosols over the Coastal Region at Dalian, Northeast China

“…In general, the AOD440nm values increased at lower wind speeds with the correlation coefficient about −0.11, which probably indicates the effect of the wind on the optical properties of aerosols [63] (Figure 7a).Figure 7b,c show similar variations in the AOD440nm with changes in both temperature and relative humidity at Dalian monitoring station with the correlation coefficient about 0.34 and 0.51, respectively. This probably indicates that a higher aerosol loading may be related to increases in temperature and relative humidity, which may increase the size of aerosol particles through hygroscopic growth and aggregation as Chen [64] and Zhang [65] have mentioned.…”

“…Figure 7a-d show the correlation of AOD 440 nm with wind speed, temperature, relative humidity, and PM 10 , respectively, at Dalian monitoring station based on the instantaneous data. In general, the AOD 440 nm values increased at lower wind speeds with the correlation coefficient about´0.11, which probably indicates the effect of the wind on the optical properties of aerosols [63] (Figure 7a). Figure 7b,c show similar variations in the AOD 440 nm with changes in both temperature and relative humidity at Dalian monitoring station with the correlation coefficient about 0.34 and 0.51, respectively.…”

Impact of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidence

“…eastern China in this study). Eastern China, as a highly urbanised region, with the rapid increase of industrial and automotive emissions, is frequently characterized by poor air quality (Ding et al, 2008;He et al, 2012). Therefore, establishing a predictable relationship between circulation pattern and air quality is important for early prediction of polluted episodes.…”

Study of Aerosol Optical Properties Based on Ground Measurements over Sichuan Basin, China

“…Except for the range of 0.00-0.30, the AOD at 440 nm increased with an increasing Ångström exponent, which illustrated that fine particles were responsible for the high AOD over the Sichuan Basin. He et al (2012b) pointed out that the wind speed and direction could affect aerosol optical properties. Fig.…”