Study On The Deposition Fluxes Of Aerosols And Nitrogen Over The Yellow Sea

Atmospheric deposition is one of vital paths for atmospheric substance input to oceans. In the open ocean or some regional seas lacking of nutrients, atmospheric deposition is also an important source for nutrients necessary for organisms. Among those elements loaded in aerosols, nitrogen is a key element to biological growth, controlling marine biological structure, function and biodiversity. Atmospheric deposition is found to be a major N source for many terrestrial and marine ecosystems. Therefore it is of great significance to understand the influence of atmospheric deposition on substance transportation, the recycle of nutrient and terrestrial, marine ecosystems.Using the data collected by the China-Japan joint project'Aeolian Dust Experiment on Climate Impact(ADEC)'in 2002-2003 and Air Pollution Index (API) in 2005-2006, we compared different approaches for estimating a reasonable range of the deposition fluxes of aerosols and nitrogen over the Yellow Sea. The impact of dust weather on the deposition fluxes was also studied. It indicated that the deposition fluxes estimated by exponential decay or linear interpolation were close to the observation data, but there was a relatively large error for estimation by a single point data. The dry deposition fluxes of TSP and nitrogen over the Yellow Sea were about 0.86 ~ 1.50g/(m2·mon) and 14.0 ~ 27.9mg/(m2·mon) respectively in 2002-2003. In 2005-2006, the deposition fluxes were 0.54 ~ 1.19g/(m2·mon) for TSP and 9.86 ~ 22.2mg/(m2·mon) for nitrogen. The seasonal distribution of the deposition fluxes of TSP was from high to low value in spring, fall, winter and summer, while the seasonal variation of nitrogen was in spring, summer and fall. The contributions of dust weather to the concentrations and deposition fluxes of TSP reduced with longitude from west to east, and the impact of dust weather on the deposition fluxes of aerosols mainly focused on those of the large particles. The contributions of dust weather to the deposition flux of nitrogen in Qingdao and Fukuoka were 19.1mgN/(m2·mon) and 13.0mgN/(m2·mon), respectively. Additionally, the anthropogenic activities on the West of the Yellow Sea had impact on deposition fluxes of aerosols.The size of aerosols determines their life span, physical and chemical characteristics, and places some influence on atmospheric mass generation and circulation. The statistical characteristics of aerosol size distribution under different weather conditions are important for better exploring the sources and the transportation of aerosols in the atmosphere. The number and mass size distribution of aerosols over the Yellow Sea were analyzed by using the observed data on Qianliyan Island and that of ADEC in 2002-2003. It suggested that the daily variations of the number size distribution were influenced by many factos such as the stability of the atmospheric boundary, the generation of secondary aerosols and the wind direction. The number of aerosol particles increased obviously in the heavy fog weather. The number concentration of aerosols over the Yellow Sea was lower than that in urban area but higher than that over the South China Sea. In the west of the Yellow Sea, the mass size distribution of aerosols was obviously influenced by the dust weather in spring and coal combustion in winter. In the east of the Yellow Sea, the mass distribution was also impacted by the dust weather in spring, but influenced little by coal combustion in winter. The dust weather changed the aerosols mass size distribution over the Yellow Sea, and obviously increased the peak value of the coarse particles...