基于NOAA19卫星资料通道误差特征的Huber-VarQC变分质量控制研究

Study on variational quality control of Huber model based on observation errors of NOAA19 satellite data channels

  • 摘要: 卫星资料同化是改善数值预报初始场质量的重要的方式,但受卫星资料观测误差的限制,导致部分可用卫星资料的有效同化率偏低,从而降低了卫星资料对同化分析的贡献。变分质量控制方案通过改变资料分析权重使不同质量观测资料得到合理应用,进而能够有效改善同化分析性能。基于能更合理表征卫星资料非高斯观测误差的Huber-VarQC变分质量控制方案,针对不同卫星通道的观测误差特征分别优化其相关参数,使同化系统能根据各通道不同的观测误差特征调整观测对同化分析的权重,从而提升卫星资料的利用率与同化效率,进而改善卫星资料的同化分析质量。试验结果表明:Huber-VarQC方案能较好刻画不同通道卫星资料观测误差的“厚尾分布”特征;分通道统计卫星观测误差并优化Huber-VarQC变分质量控制方案,能够最大限度发挥该方案的实际应用潜力和卫星资料对分析的贡献;分通道的Huber-VarQC方案可以依据各通道观测误差的特征分配资料合理的权重,进而提高极轨卫星微波观测资料的有效同化率,在吸收资料有益信息的同时降低有害信息对同化分析的负面影响,从而提高卫星资料的有效同化率,提高其对改善同化分析场的正贡献,尤其对中小尺度强降水预报效果的改善更加显著。

     

    Abstract: Satellite data assimilation is an important method for improving the quality of the initial field in numerical weather prediction. However, the restriction of observation error in satellite data will lead to low effective assimilation rate of some available satellite data, which in turn reduces the contribution of satellite data to the assimilation analysis. The variational quality control scheme adjusts the weight of data to ensure that observations of different quality are utilized appropriately, thereby effectively improving the performance of the assimilation analysis. Based on the Huber-VarQC variational quality control scheme, which more appropriately characterizes the non-Gaussian observation error of satellite data. It optimizes the relevant parameters for different satellite channels according to their specific error characteristics, allowing the assimilation system to adjust the weight of observation in the assimilation analysis based on the different observation error feature of each channel. This enhances the utilization and assimilation efficiency of satellite data and improves the quality of the assimilation analysis. The experimental results indicate that the Huber-VarQC scheme can effectively capture the "fat-tailed" distribution characteristics of observation error in satellite data across different channels. Statistically analyzing satellite observation error by channel and optimizing the Huber-VarQC variational quality control scheme can maximize the practical application potential of this approach and enhance the contributions of satellite data to the analysis. The channel separation Huber-VarQC scheme can allocates appropriate weight to the data based on the error characteristics of each channel, and then increasing the effective assimilation rate of polar orbit meteorological satellite microwave observation data. This approach not only incorporates beneficial information from the data but also mitigates the negative impact of harmful information on the assimilation analysis. As a result, it enhances the effective assimilation rate of satellite data and improves its positive contribution to the assimilation analysis, particularly demonstrating significant improvements in the forecasting of micro- and meso-scale heavy precipitation events.

     

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