闪电引起的天电和红闪现象的模拟研究

用二维时变的电磁场模型，研究了闪电放电产生的天电和红闪现象.模拟结果表明：闪电放电产生的电场包括辐射场和准静电场.辐射场在地面-电离层波导中传播形成大气中的天电.由准静电场引起的N₂分子第一个正波段的光辐射形成红闪现象.用模拟的方法表明，在红闪的空间结构发生变化的过程中，有明显“V”形结构; 在红闪的整体机构中，中心部分是一个光强度相对较强的核，周围包着光强度相对较弱的晕. 关键词： 红闪 天电 电磁场模型     

The study and applications of photochemical-dynamical gravity wave model Ⅱ-- The effects of stable gravity wave on chemical species distribution in mesosphere

A nonlinear, compressible, non-isothermal gravity wave model that involves photochemistry is used to study the effects of gravity wave on atmospheric chemical species distributions in this paper. The changes in the distributions of oxygen compound and hydrogen compound density induced by gravity wave propagation are simulated. The results indicate that when a gravity wave propagates through a mesopause region, even if it does not break, it can influence the background distributions of chemical species. The effect of gravity wave on chemical species at night is larger than in daytime.     

The study and applications of photochemical-dynamical gravity wave model Ⅰ--Model description

A two-dimensional, nonlinear, compressible, diabatic, nonhydrostatic photochemical- dynamical gravity wave model has been advanced. The model includes diabetic process produced by photochemistry and the effect of gravity wave on atmospheric chemical species. In the horizontal direction, the pseudospectral method is used. The finite difference approximations are used in vertical direction z and time t. The FICE method is used to solve the model. The model results on small amplitude fluctuation are very close to those of linear theory, which demonstrates the correctness of the model.     

一种改进的自适应卡尔曼滤波及在组合导航中的应用

总结了常用的自适应滤波的方法,并提出一种新的自适应卡尔曼滤波技术,它克服了传统滤波器的不稳定问题,因为传统的卡尔曼滤波过程依赖于系统过程和测量过程的数学模型和其统计模型的正确性的滤波技术.自适应过程是利用测量新息序列和状态修正序列在估计移动窗内是分段静态,来直接估计系统噪声协方差Q和测量噪声协方差(R).仿真结果表明此方法可以提高GPS/INS组合导航系统的精度和可靠性.