FY-3A气象卫星臭氧总量数据的质量控制方案及其在台风Tembin (2012)和Isaac (2012)中的应用

Quality Control of FY-3A Total Column Ozone and Its Application in Typhoons Tembin(2012) and Isaac(2012)

我国第二代极轨气象卫星"风云三号"A星(FY-3A)上搭载的紫外臭氧总量探测仪(Total Ozone Unit,TOU)每天可以提供一次覆盖全球的臭氧总量观测。为了在数值预报中应用TOU的臭氧资料,从资料同化角度发展了一套质量控制方案。首先基于臭氧总量和平均位势涡度的高相关性建立了逐日动态更新的臭氧线性回归预报模型,然后使用双权重算法对臭氧资料进行质量控制。将该质量控制方案应用于台风Tembin(2012)和Isaac(2012)个例,试验结果说明该方案可以体现出臭氧总量和平均位势涡度之间相关关系的逐日变化,识别出的离群资料百分比随时间变化较稳定,可以保留原始资料的主体信息,并且显著降低了原始资料的标准差。同时,质量控制后的臭氧数据与统计拟合量更加一致,观测减拟合的概率密度函数分布形式也更接近高斯分布,有利于后续的资料同化。

The Total Ozone Unit （TOU） on board the second-generation polar orbiting meteorological satellite of China, Fengyun-3A （FY-3A）, provides once-daily global total ozone observations. To apply the TOU ozone data in numerical weather prediction, a quality control scheme is developed, viewed from the assimilation point. In the first step, a daily updated linear regression model, which links the total column ozone to the mean potential vorticity （MPV）, is established. Following this step, the biweight algorithm is applied to remove the outliers. Numerical results implementing the proposed quality control scheme in typhoon Tembin （2012） and Isaac （2012） reflect daily variations of correlation between total ozone and MPV. The total percentage of outliers identified by this scheme is highly stable with the change of time, and the main information of ozone data is maintained whereas the standard deviation is reduced significantly. In addition, the ozone data after quality control are more consistent with the statistical fitting variable. The distribution of the observed-minus-fitting Probability Density Function becomes nearly Gaussian, which is conducive to data assimilation.