Analysis On The Influence Of Meteorological Parameters On Marine Aerosols Particle Number Density Distribution In Typical Seas

Atmospheric aerosol has great impacts on the atmospheric environment and climate,as well as ineligible impacts on human living and production.Understanding the physical and optical characteristics of atmospheric aerosols and establishing models can help humans beings to understand the climatic effect of atmospheric aerosols and to solve atmospheric problems that are harmful.Therefore,it is imperative to study on the characteristics of atmospheric aerosols.Marine aerosols,as a component of atmospheric aerosols,can directly or indirectly affect the energy budget of earth-atmosphere system and climate change in various ways.On the one hand,the study on marine aerosols is helpful to a further understanding of the ocean-atmosphere interaction and the impact of the seas on global climate changes.On the other hand,marine atmospheric aerosols involved in various air-sea exchange processes,having a significant influence on the marine atmospheric circulation.Therefore,the study on the topic of marine atmospheric aerosol microphysical characteristics has become an important subject for scholars at home and abroad.There are some common meteorological parameters of atmospheric aerosols,namely,temperature,relative humidity,wind speed,wind direction,air pressure,as well as rainfall and common atmospheric aerosol optical parameters,namely,visibility,absorption coefficient,scattering coefficient and extinction coefficient.The main analysis of this paper was the influence of the particle number density distribution affected by meteorological parameters.There are some common instruments for measuring atmospheric parameters,namely,Forain Weather System,visibility sensor,photoacoustic spectroscopy,lidar,optical particle counters,etc..In this paper,firstly,the physical and optical characteristics of atmospheric aerosols are reviewed,such as definition,classification,size and source of atmospheric aerosols.The definitions of meteorological and optical parameters are introduced in detail.The measurement methods,equipment and principles of atmospheric aerosol concentration,particle size distribution and visibility are also given.Then,the spectral pattern of the marine aerosol particle number density distribution was analyzed and the influences of relative humidity and wind speed on the particle number density distribution are studied.Finally,the extinction and absorption characteristics of atmospheric aerosols and the relationships between parameters in typical sea areas are analyzed.Based on aerosol data measured in the offshore sea of Maoming,Guangdong and over the Pacific and Indian Ocean from August 2004 to October 2018,this paper studied the variation of aerosol particle number concentration and particle size distribution depending on meteorological conditions.The data consist of two parts:(1)the particle number of atmospheric aerosol measured by the Optical Particle Counter(OPC);(2)it was measured that atmospheric temperature,relative humidity,air pressure,wind speed and other meteorological parameters by Forain Weather System etc..The variation of particle size distribution on different meteorological conditions was analyzed i.e.the variation of particle size distribution was simulated under different relative humidity and wind speed following by the value of theoretical analog was compared with that of actual measured.The results showed that,on the one hand,it is realistic to retrieve the influence of relative humidity on particle distribution by using the model of r(RH)/r=(1-RH)1/2.9.On the other hand,it is reasonable to utilize the model of lgN=a*U+b to retrieve the effect of the wind speed on particle size distribution.In general,the degree of fit between the theoretical model and the actual measurement is very high,indicating important guiding significance for establishing the marine atmospheric aerosol model.Analysis showed that the error sources are mainly contributed from the measurement error of the instrument and the inversion error of the formula.Although there are some errors in the results,it has reference significance for studying the influence of meteorological parameters on the particle distribution of different sea areas.In addition,this paper analyzed the variations of atmospheric temperature and relative humidity in coastal and offshore area of Maoming.The daily variations of relative humidity is analyzed and compared with variations of visibility,temperature,absorption coefficient and scattering coefficient.The temperature,humidity,visibility and particle number density spectrum were analyzed and compared between sunny and rainy days.And the particle number density distribution spectrums were analyzed and compared between coastal and offshore areas.It puts forward some prospects for the next step:to improve the integrity of the data by improving the atmospheric measuring system;to improve the accuracy of the simulation by improving the meteorological model;to broaden the applicability of the model and to study the feasibility of predicting marine aerosol optical parameters by broadening the exploration of the sea area.