热层大气密度动态修正模型研究

Study on the model for dynamic correction of thermospheric density

为构建具有密度误差原理级修正的热层大气模型动态修正软件系统,首先,根据温度垂直剖面计算方法,对拐点和外逸层2个边界温度计算函数按经纬度球谐系数展开,研究基于模型和实测密度估计修正系数的方法;从数值计算方面,将条件方程泰勒展开线性化迭代求解得到修正系数。然后,融合修正理论和数值方法,构建热层大气密度动态修正模型系统。之后,针对磁暴、磁静事件分类评估系统性能,结果显示修正后模型的预报准确性较MSIS00模型显著提升——预报相对误差磁暴期平均下降33.8个百分点,磁静期平均下降9.1个百分点。最后,分析边界温度修正量的序列,得到其主要变化规律。期望通过热层大气模型动态修正系统的研究与实践,为热层大气密度的高精度预测需求提供解决方案。

In order to construct a software system for dynamic correction of thermospheric model with density error principle-level correction,firstly,based on the vertical temperature profile calculation method,the calculation function of inflection point and exosphere boundary temperature was established according to the spherical harmonic coefficient of latitude and longitude.A method of estimating the correction coefficient based on the model and the measured density was studied.From the aspect of numerical calculation,the correction coefficient was obtained by iteratively solving Taylor expansion linearization of the conditional equation.Then,the dynamic correction model system was constructed by combining the correction theory and numerical method.Afterwards,the system performance was evaluated according to the classification of magnetic storms and magnetostatic events.The results show that the forecast accuracy of the correction model was significantly improved compared with that of the MSIS00 model.The relative errors of the forecast decreased by 33.8%during magnetic storm and 9.1%during magnetic quiet respectively.Finally,the sequences of boundary temperature correction were analyzed and the main variation rules were obtained.Through the research and practice of the dynamic correction system of the thermospheric model,it is expected to provide a solution for the high precision forecast of themospheric density.