论文部分内容阅读
Dust particles showed a significant growth in size during their travel in the marine atmosphere from China to Japan.Estimates of the growth indicated that mixing with sea salt had caused the size distributions to shift to larger ranges approximately by 0.4 ~ 0.8 μm.The growth had a strong correlation with sea salt but was independent from sulfate and nitrate.These results suggest that the interaction of dust particles and sea salt is an important process in size and composition changes of dust particles during their long range transport.Because size and density of a particle are two key factors governing its gravitational settling in the air,the interaction of sea salt and dust will consequently affect the flux of mineral dust to sea surface.It has been well known that the input of continental mineral dust to the ocean via atmospheric dispersion plays an important role in the marine ecosystem.It is therefore very important to assess the influence of sea salt on the gravitational settling of dust particles to sea surface in the marine boundary layer.In this presentation,some results of a primary investigation on the influence of gravitational settling velocity and dry deposition flux will be reported,in addition to those about particle growth.The investigation is based on the Stokes gravitational settling theory and some recent observational data.The velocity of dust particles is increased by sea salt combination,and results of an estimate of the sediment flux of mineral dust from data of six dust events in southwestern Japan will be reported.