TEMPORAL AND SPATIAL DISTRIBUTIONS OF AEROSOLS OVER THE BOHAI SEA
渤海气溶胶时空分布研究

Aerosol optical thickness(AOT) data between 2003 to 2008 obtained using a ship-based multiband sun photometer were taken to study the temporal and spatial distributions and the influencing factors of AOT,turbidity coefficient(β),and ngstr m exponent(α) over the Bohai Sea.We obtained a total of 212 datasets from eight cruises and two fix-point measurements.There were 72 datasets in 2003,21datasets in 2004,98 datasets in 2005,and 21 datasets in 2008.Intra-day variations of AOT,β,and α were inconspicuous.The mean values and ranges of AOT,β,and α decreased from June to September.The values of AOT,β,and α in June,August and September were larger than those in March due to smog,sandstorm,and ocean moisture.In most areas within 25 km offshore,AOT and β decreased with increasing distance from shore.However,the variation of α did not show a clear trend.Over the Bohai Sea,the influence of β on AOT was more significant than α.The relationship between AOT and β was described by AOT = 2.52×β + 0.07 when α is greater than 0.8,and he relationship became AOT = 1.20×β + 0.16 when α is smaller than 0.8.We classified the aerosols into two types based on whether α was greater than 0.8.The influence of small changes in aerosol particle size on AOT may be ignored for certain types of aerosols.