Sporadic E (Es) layers are irregular structures that occur at the E-layer height of the ionosphere, significantly affecting the reliability and accuracy of wireless communications, navigation, and satellite remote sensing. This study utilized the S4max data collected from the Constellation Observing System for the Meteorology, Ionosphere, and Climate (COSMIC) occultation observations from 2007 to 2016 to identify the Es layer and investigate its climatological variations. The Horizontal Wind Field model (HWM14), in conjunction with the International Geomagnetic Reference Field model (IGRF13), is used to calculate vertical ion convergence (VIC) and analyze its correlation to the Es layers. The results of this study showed that the occurrence of Es has apparent hemispheric asymmetry. In the mid- and low latitudes, Es layer activity is more intense in the summer hemispheres, with center peak altitudes of around 105 km. The summer hemisphere exhibits a semi-diurnal periodic pattern, whereas the winter hemisphere shows a weakened diurnal variation. Simulation studies indicate that VIC induced by neutral wind shear contributes to the asymmetry in Es layer activities observed between the Northern and Southern hemispheres, and the zonal wind shear plays a more critical role than the meridional wind one.

In order to eliminate the influence of the high-order magnetic dipole modes in the short-wave range of the high-refractive-index dielectric grating, we propose a thin film filter to cut off the “useless” short-wave. In this way, the high-order magnetic dipole can be suppressed, and the quality of the structure color is highly improved after the thin film filter cut off the incident light in the non-resonant band. The combined application of the thin film filter and the grating filter not only avoids the problem of too big film layer thickness, but also reduces the manufacturing process cost. For example, the film system (basic film system 0.5 L H 0.5 L) and thickness of green, 15° and 45° incident film filters are 21 layers, 1.76 μm and 41 layers, 4.02 μm. The color coordinates corresponding to the calculation results occupy a large area on the Commission Internationale de l’Eclairage 1931 (CIE 1931) chromaticity diagram, which proves that this design scheme can effectively improve the structural color quality. This method obtains excellent theoretical simulation results. This has important implications for high-end imaging equipment and sensors.