Temporal And Spatial Analysis Of Tropospheric Ozone,Simulation Of Influencing Factors And Surface Ozone Estimation

As a trace gas wihch only constitutes little of the atmospheric constituents,ozone is a very important constituent of it.Due to the altitude of the ozone,it can be devided into stratospheric ozone and troposphere ozone.Stratospheric ozone protects life forms on Earth from the Sun's harmful ultraviolet light and it also plays an important role in climatic changes.Stratospheric ozone has significantly decreased since the early 1970's,and ever since the discovery of the Antarctic ozone depletion,it has been a focus of attention by scientists and the public for three decades.On the other hand,troposphere ozone is considered as a pollutant and is toxic to both ecosystem and men.Moreover,it also plays an important role in climatic changes.After the ground-based verification,error correction and consistency evaluation of TOMS/SBUV and OMI/MLS global tropospheric ozone data,the temporal and spatial distribution for global tropospheric ozone was analyzed.In addition,the summer tropospheric high-value centers and significant growth trends in the North China Plains were studied in depth,and the contribution and mechanism of several relative impact factors on tropospheric ozone over North China and surrounding regions were quantitatively discussed.At the same time,considering that ozone can cause serious harm to human health when it is enriched in the near-surface layer,this study further analyzes the spatial distribution and aggregation characteristics of near-surface ozone in China.This study regards atmospheric ozone as the research object,including three horizontal scales of the world,China,and North China,as well as two vertical scales of troposphere and near-surface.It aims to discover and explain the temporal and spatial variation of ozone at different scales.This study provides research references for ozone mechanism analysis and has reference significance for developing regional tropospheric ozone uplift and ground-level ozone pollution response measures.The main findings of this study are as follows:(1)A new error correction scheme is proposed:OMI/MLS tropospheric ozone data was corrected with latitude-month factors,and then error-corrected OMI/MLS data and improved probability mapping method with 5 pixel schemes were used to correct the TOMS/SBUV tropospheric ozone data.After ground-based verification and consistency evaluation,it was found that the consistency between two error-corrected satellites tropospheric ozone data and ground-based data was improved by 44.89%.Then a set of tropospheric ozone data with longer time range?better consistency and wider spatial coverage is obtained.(2)Temporal and spatial analysis of error corrected tropospheric ozone data reveals several simlar results with former researches.While global tropospheric ozone showing an overall increaseing trends for both yearly and seasonal,and the increasing trend can be divided into two stages:smooth fluctuation and significant increasing.At last,the elevating trend of summer tropospheric ozone in this area is significant(0.154DU/year).But the increase trend of summer tropospheric ozone over North China Plains is larger than other researcher's results,which is related to the post-processing tropospheric ozone data used in this study.(3)The crop residues burning in the North China Plains led to a 4.0 DU increase of the tropospheric ozone in East Asia in June,accounting for 8%of the total tropospheric ozone in June for the region.In addition,ultraviolet radiation?the zonal wind and the meridional wind are three other main factors.These four main influencing factors together explain more than 90%of the variation of tropospheric ozone of this region.It is revealed that the summer crop straw burning in the North China Plains leads to an increase in NO_X concentration which leads to a significant net ozone production.Then ozone and the ozone precursors are transmitted to the downwind region through the atmospheric circulation which leads to the emergence of high value region of tropospheric ozone in East Asia.(4)Spatial analysis of ground-based ozone data of 1152 sites in China reveals that there is obvious spatial agglomeration for surface ozone,which can be divided into four major regions:North China,Southeast China,the middle and lower reaches of the Yangtze River region and the Southwest China.Sensitivity analysis indicates that there are both commonality and significant differences in the main influencing factors for each region.The most important factors for four regions are temperature.The other two second important factor are the solar radiation and the the sine values of Julian Day.In addition,the significant differences are as follows:the other two important impact factors are the wind direction and sunshine duration in North China,while in the middle and lower reaches of the Yangtze River are relative humidity and boundary layer height.In southeast China,the relative humidity is the second most important factor,while the surface pressure is another important influence factor in southwest China.