Studies On The Inversion Method Of Ozone Profile By The MAX-DOAS

In this paper we use the scattered light from MAX-DOAS in Kunming and Shanghai to study the inversion method of tropospheric and stratospheric ozone profile.At present,the MAX-DOAS inversion method for tropospheric atmospheric composition profile is widely used and relatively mature.The inversion profile with differential slant column density DSCD mainly focuses on the lower atmospheric composition.The distribution characteristics of ozone are different from other trace gases.Through simulation experiments,it is found that because the content of stratospheric ozone is significantly higher than that of the troposphere,the DSCD of the stratosphere significantly affects the DSCD of the troposphere.The typical inversion method is no longer applicable.Therefore,based on the MAX-DOAS zenith scattered light observation results,we apply the Umkehr principle to MAX-DOAS,first inverts the stratospheric ozone profile,and then use the optimal estimation method to perform conventional inversion of the tropospheric profile.In order to obtain a whole vertical ozone profile,we apply Umkehr to MAX-DOAS in Kunming and Based on the sounding profile,we use OMI ozone data,ozone sonde measurements data to make comparison and found that a good agreement.However,the region where the lower stratosphere increased sharply,the relative error to OMI and retrieve results are relatively high.The altitude region at 20-40 km is the most sensitive area of the Umkehr principle.The relative errors with the ozone sonde measurements are less than 20%,and the inversion results are reasonable.The ozone profiles above 10 km based on Umkehr principle were inputed into the SCIATRAN radiation transfer model to calculate the stratospheric DSCD to separate the tropospheric DSCD.The MAX-DOAS tropospheric ozone profile inversion results show that the maximum error between the ozone concentration and the sounding data within a height of 1km near the ground is only 8%.Due to the decrease in sensitivity of MAXDOAS inversion as the altitude increases,error increases.Due to the lack of sounding data in the Shanghai,the profile inversion has the similar trend with OMI ozone data,and the total ozone column is lower about 10%.The combination of the two methods to retrieve the ozone profile indicates that the results is stable and reliable,and it give full play to the high sensitivity and high resolution advantages of MAX-DOAS near the ground,and provide method support for continuous monitoring of near-ground ozone pollution.