风云-3A卫星TOU臭氧总量地基对比验证分析

Validation Study of FY-3A-TOU Total Ozone Using Ground-based Data

通过地基臭氧总量观测,对风云三号(FY-3A)气象卫星TOU(2009年7月至2013年12月)臭氧总量开展检验分析.结果显示,TOU臭氧总量与地基测值之间的线性相关系数达到0.95以上,相对差别(RD)为(-0.16+4.3)%.赤道地区RD随地基测值的上升明显,太阳天顶角(SZA)为70°以上时TOU臭氧总量明显下降,75°~85°有一4%^-10%不等的降幅.云量变化(0~100%)或云高变化(1~15 km)对RD的影响在±2%以内.RD随着吸收性气溶胶(AI为正值)有-2%^-5%的变化,在南半球中纬度地区明显.TOU与地基Dobson,Brewer及SAOZ光谱仪测值的RD分别为(0.6±0.17)%,(0.05±0.2)%,(0.04±0.01)%.当地基臭氧总量在200 DU以下时,TOU值低于Dobson或SAOZ测值;而在430~500 DU时,TOU高于SAOZ值2%~6%.TOU分别与Dobson,Brewer,SAOZ的RD对SZA(70°以下)、云量变化均不敏感,但TOU分别与Brewer,SAOZ的RD在云高5 km以上时或随AI的增加均出现一定的趋势特征.

Total ozone from July 2009 to December 2013 measured by Total Ozone Unit(TOU)borne on the FY-3A meteorological satellite is validated with the ground-based observations over the global five latitudinal bands,the north pole(north to 63.5°N),middle north of hemisphere(23.5°N^63.5°N),tropic zone(23.5°N^23.5°S),middle of south hemisphere(23.5°S^63.5°S) and South Pole(south to 63.5°S).The results show that the linear correlated coefficient between TOU and the ground-based data is more than 0.95.The globally average TOU Relative Difference(RD)from the ground-based data is(-0.16±4.3)%,with the respective of(0.6±3.8)%,(-0.5±3.9)%,(1.8±3.1)%,(-0.6±3.7)% and(-0.1±3.9)% over the 5 north-southward bands.The sensitivity tests suggest that TOU RD over the tropical zone evidently rises with the growth of the ground-based total ozone.The global TOU ozone RD reduces as the Solar Zenith Angle(SZA) is greater than70° and the RD may reach from-4% to-10% as SZA from 75° to 85°.The TOU ozone RD is insensitive to the variability of cloud amounts and altitudes:the RD ranges within ±2% as the cloud amount changes from 0 to 100% or the cloud altitude changes from 1 to 15 km.The TOU ozone RD is sensitive to the absorptive aerosol characterized by the positive Aerosol Index(AI),and it may decrease from-2% to-5% over the middle of south hemisphere as the AI from 1 to more than 2.The globally respective RD of TOU ozone to Dobson,Brewer and SAOZ observations is(0.6±0.17)%,(0.05±0.2)% and(0.04±0.01)%.TOU RD is generally negative as the Dobson or SAOZ total ozone is lower than 200 DU,while it generally 2%~6% as SAOZ total ozone is 430~500DU.The respective RD of TOU to Dobson,Brewer and SAOZ is also insensitive to variations of SZA(less than 70°) or the cloud amounts,however,the RD of TOU respective to Brewer and SAOZ may behavior some small trend with the occurrence of high cloud or positive AI.