135.6nm夜气辉峰值电子密度反演算法及误差

Retrieval Algorithm and Precision Analysis for N_mF_2 of Nighttime OI135.6 nm Emission

根据夜间135.6 nm大气辉光光强与F_2层峰值电子密度N_mF_2平方成正比的物理机制,在前期夜间135.6 nm气辉辐射激发模型研究的基础上建立了峰值电子密度的反演算法,把全球经纬度分成若干格点,每个格点的电离层及中性成分信息分别由IRI2000和MSISE90提供,将电离层及中性成分廓线输入夜气辉辐射激发模型,计算每个格点135.6 nm气辉的辐射强度,然后将各个格点的135.6 nm气辉辐射强度与电离层廓线输入的N_mF_2平方拟合得到气辉强度与N_mF_2的转换因子.利用此方法可获得不同地方时、季节和太阳活动周期的转换因子组成查算表,进而根据实际探测的135.6nm气辉辐射强度反演相应时空的N_mF_2.最后对该算法的反演误差进行了综合分析,为该算法适用的时空特性提供重要理论支撑.

The nighttime O1135.6 nm airglow is proportional to the square of the maximum elec- tronic density of ionospheric F2 layer （NmF2）. Based on the previous studies of the nighttime O1135.6 nm airglow radiative and emissive model, the retrieval algorithm of NmF2 derived from nighttime O1135.6 nm emission was presented. The column emission rate is calculated for each grid point of the nighttime airglow radiative and emissive model. The electron density profile, O＋ density profile, and electron temperature profile are taken from the IRI2000 model, and the neutral compo- nents are taken from MSISE90 model. In order to derive the relationship between the O1135.6 nm column emission rate and NmF2, the column emission rate is fitted to the square of NmF2 linearly. The ratio of the square of N^F2 to the column emission rate is obtained from the slop of the fitting line, which gives the relationship between NmF2 and the emission. According to the measurements of the OI 135.6 nm column emission rate, NmF2 are retrieved. Finally, the error of the retrieval method is analyzed, which provides important theoretical supports for the time and space applicability of the algorithm.