Lognormal distribution of the observed and modelled neutral thermospheric densities
Lognormal distribution of the observed and modelled neutral thermospheric densities
复制标题
观测和模拟的中性热层密度的对数正态分布
DOI：
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发表时间：
2007
期刊：
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通讯作者：
A. Bezdek
中科院分区：
文献类型：
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作者：
A. Bezdek
对于分析任何类型的测量，重要的是估计测量误差的概率分布。当使用最小二乘拟合对观测进行建模时，误差的分布在选择要最小化的优值函数方面起着至关重要的作用，因为非正态分布的误差（例如，离群值或在平均值周围显示不对称性）可能会严重扭曲估计模型参数的最小二乘拟合。利用230-750 km高度的CACTUS加速度计数据，我们将证明常用的中性热层密度半经验模型（MSIS，DTM）与观测密度之间的统计关系符合对数正态分布，即观测值与预报值之比的对数近似服从正态分布。这一实验事实可用于中性热层密度的模拟。
For analyzing measurements of any kind, it is important to estimate the probability distribution of the measurement errors. When modelling the observations using least-squares fitting, the distribution of the errors plays a vital role in choosing the merit function to be minimized, as unnormally distributed errors (e.g. outliers, or displaying asymmetry around the mean) may substantially skew a least-squares fit of estimated model parameters. Using the CACTUS accelerometer data covering heights of 230–750 km, we will show that the statistical relationship between the commonly used semi-empirical models of neutral thermospheric density (MSIS, DTM) and the observed densities is consistent with lognormal distribution, i.e. the logarithm of the ratio of the measurements to the predictions is approximately normally distributed. This experimental fact may be applied in modelling the neutral thermospheric density.