基于NOAA19卫星资料微波温度计和湿度计通道误差特征的Huber-VarQC变分质量控制研究

Huber-VarQC variational quality control based on channel errors characteristics of microwave thermometer and hygrometer from NOAA19 satellite data

  • 摘要: 卫星资料同化是改善数值预报初始场质量的重要方式,但由于其观测质量总体上相对偏低,通常仅有部分卫星资料参与同化分析,导致其有效同化率偏低。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NOAA19/AMSUA和MHS卫星资料非高斯观测误差的Huber-VarQC变分质量控制方案,针对NOAA19/AMSUA和MHS不同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。结果表明:Huber-VarQC变分质量控制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,从而充分发挥卫星资料对同化分析的正贡献并提高同化效率,获得更准确的分析场。

     

    Abstract: Satellite data assimilation is an important method for improving the quality of the initial field in numerical weather prediction. However, due to the generally low observation quality, only a portion of the satellite data typically participates in the assimilation analysis, resulting in a low effective assimilation rate. 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 errors of the NOAA19/AMUSA and NOAA19/MHS satellite data, the relevant parameters for different satellite channels are optimized according to their specific error characteristics, allowing the assimilation system to adjust the weight of observation in the assimilation analysis based on different observation error features of the NOAA19/AMUSA and NOAA19/MHS at each channel. This enhances the utilization and assimilation efficiency of satellite data and improves the quality of the assimilation analysis. The experiment results indicate that the Huber-VarQC scheme can effectively capture the "fat-tailed" distribution characteristics of observation errors in satellite data across different channels. Statistically analyzing satellite observation errors 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 allocate appropriate weight to the data based on the error characteristics of each channel, and then increase 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. It improves the positive contribution of satellite data to the assimilation analysis field and enhances assimilation efficiency, resulting in a more accurate analysis field.

     

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