Remote Sensing Estimation Model Of Tropospheric Ozone Over China

The OMI and MLS instruments on broad the Aura satellite are used to derive Tropospheric Column Ozone(TCO).In this study,TCO is based on the Tropospheric Ozone Residual(TOR)method.After accuracy validation and error analysis for tropospheric ozone estimation model,this study investigated the spatiotemporal distribution of TCO concentrations in China from 2013 to 2017,including Beijing,Chengdu,Guangzhou,Lanzhou,Shanghai,and Urumchi.Main works are summarized as follows:(1)Construction of Tropospheric Ozone Estimation Model.Spatial matched and height matched MLS ozone profile data with NCEP/NCAR tropopause reanalysis data to obtain Stratospheric Column Ozone(SCO)concentrations.The Kriging interpolation method was used to eliminate the spatial scale differences between the Total Column Ozone(CO)and SCO.Finally,the TOR method was used to calculate the TCO.(2)Accuracy validation and error analysis of Tropospheric Ozone Estimation Model.The ozone data from the four sites of Hong Kong,Japan,the Netherlands,and Poland,located at the three latitudes of the Northern Hemisphere,are used as validation data.The results show that the Tropospheric Ozone Estimation Model increases the average correlation coefficient of the tropospheric ozone concentration of OMI ozone official profile data from 0.35 to 0.62.The monthly Tropospheric Ozone Estimation Model data set has increased the average correlation coefficient of the official NASA tropospheric ozone average data set from 0.71 to 0.78.The average tropospheric ozone estimation model at the mid-and low-latitudes in Hong Kong and Japan has an average error of about 10%.The average error at high latitudes in the Netherlands and Poland is about 13%;the average error in spring and autumn is about 9%,and that in summer and winter seasons is about 11%.(3)Analysis of temporal and spatial distribution of TCO in China during 2013~2017.Spatially,the average annual concentration of tropospheric ozone concentration in the east is higher than that in the west,and the high values are distributed in the Beijing-Tianjin-Hebei,Yangtze River Delta,and Pearl River Delta cities,and in the Central Plains and Chengdu-Chongqing regions.The low values are mainly in the Qinghai-Tibet Plateau.Temporally,the country's tropospheric ozone concentration has been growing slowly year by year.The average annual concentration in 2017 has increased to 32.8 DU,which is an increase of 3.6% from the average annual concentration of 31.65 DU in 2013.The minimum monthly average concentration of tropospheric ozone has increased by 7.4% from 2013 to 2017,and the maximum value has increased by 2.3%.(4)Analysis of TCO in Typical Cities during 2013~2017.The average annual concentration of TCO in 2013-2017 was higher in three cities in the southeast of Hu-Line than in three cities in the northwest.The highest annual tropospheric ozone concentration in six cities is Shanghai,and the lowest is Lanzhou.The period in which the TCO average concentration is greater than 40 DU is earlier and lasts longer in three cities in the southeast of Hu-Line than in three cities in the northwest.