| The climate and the environment effect of aerosols is an important research field widely concerned by scientists and has become a focus of global change research and one of the frontier science problem.However,there is great uncertainty to evaluate the effect of aerosol on the global environment and climate change.Therefore,to further study of variation characteristics and its influencing factors of aerosols which reduce the uncertainty of environment and climate change impact assessment has important scientific significance.The Tibetan Plateau is a sensitive and vulnerable area for climate change.In recent decades,the rapid increase in the aerosol pollution in Tibetan Plateau has seriously affected the climate and ecological environment.Therefore,it is of great significance to study the impacts of transport and deposition of aerosols in the Tibetan Plateau region.The proposed research project is designed to conduct a comprehensive analysis for the interactions between the aerosol pollution and the climate change in the Tibetan Plateau.The study will integrate various methods,including satellite data,ice core analysis data,in-situ surface measurement,global meteorological reanalysis data,and numerical models.This paper based on the mesoscale chemical model WRF-Chem(Weather Research and Forecasting with Chemistry)and black carbon observation data in South Asia region,firstly compared the simulation results with the observation data to test and verify the reliability of model,and secondly discussed the annual and seasonal variation of the black carbon and biomass combustion contribution for the black carbon concentration and forming reason,get the following preliminary conclusion:With the contrast of the monthly average black carbon aerosol concentration of 32 sites in south Asia,the regional BC concentration presented single valley change trend with two head high and middle low in the whole 12 months,which means the high concentration appears in autumn and winter,while lower concentration appears in spring and summer.Kolkatai is the highest city black carbon aerosol concentration in all 32 sites in,the annual average concentration of black carbon aerosol is 12.11 ?gm-3,in January reached to 27.86 ?gm-3.From the point of view of the whole area,the black carbon aerosol concentration of four divided areas has obvious seasonal variation characteristics which present the highest in the winter monsoon and the minimum in summer monsoon.Because the outbreak of the Asian monsoon and the arrival of the rainy season,the range and distribution of black carbon aerosol is significantly reduced.The BC was second in post-monsoon and third in pro-monsoon.But slightly different is that the black carbon aerosol concentration in southern India in pro-monsoon of is higher than post-monsoon.Comprehensive contrast fire burning point number and carbon emissions during the period of 2003-2016 in research areas,it can be seen that the fire number in northeast India is the most,and the second is the northern India,later is southern India and western India.The fire burning carbon emissions of four areas also presents the same trend,in northeast India was the first,and second in turn is in northern India,southern India,and western India.From a point on the change trend of the number of years,gradually increase in 2003,reached its peak in 2009,to 2016 after reducing year by year,which decreased significantly in 2008 and 2008.Annual variation trend of the fire burning carbon emissions also presents the same trend,fire burning in your 2008 and 2011 carbon subsidiary is lower than other yearsWe select 2012 and 2016 in January(on behalf of black carbon high season)and April-May(high fire season)to simulate the biomass burning effect with two kinds of scenario settings for BB emissions zero and not respectively.Through the comparison of the calculated and modeled BC we can see the BC values under the zero BB discharge scenario simulation significantly higher than the BB zero emissions scenario simulation values.Simulation of the high fire season has an obvious advantage over high black carbon season because the simulation result was more close to the observation,show that FINN biomass combustion emission source is reliable,and the contribution of biomass burning for black carbon is huge in south Asia.Contrast the different month in April and May,the simulation results in April significantly better than in May.In April 2012 and 2016 BB for BC's contribution rate in the whole study area were 38% and 53% respectively.The BC in 2016 was close to the observed value of 96%.In May 2012 and 2016 the BB for BC's contribution rate in the whole study area was same 22%.BC were close to the observed value too,reached 79% and 79% respectively.This paper take the black carbon emitted by biomass burning in South Asia for example,discussed and simulated the influence of the regional aerosol transmission on the qinghai-tibet plateau got some preliminary understanding.The study focused on(1)the characteristics of aerosol emissions in the surrounding regions of the Tibetan Plateau,(2)long-range transport by monsoon and westerly for aerosols;and(3)deposition characteristics of aerosols in the Tibetan Plateau.This study results will provide the valuable scientific information regarding the aerosol pollution in the Tibetan Plateau. |
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