Recent  

In the terrestrial ionosphere sporadic (metallic) layers are formed. The formation of these layers are related to the action of atmospheric waves. These waves, also named tides, are due to the absorption of solar radiation in the atmosphere. We investigated the role of the tides with 8-hour period in the formation of the sporadic layers. The study was conducted using ionosonde and meteor radar data, and computing simulations. The 8-h tides intensified the density of the sporadic layers.

The solar eclipse of 5–6 January 2019 perturbed the ionospheric electron density, N, observed with the receiver at the Harbin engineering university and 14 HF broadcasting stations ~1,000 km around. It was accompanied by ±1.5 Hz Doppler spectrum broadening, ±0.5 Hz Doppler shift, fD, variations, 15 min period variations in fD caused by 1.6–2.4 % perturbations in N, and 4–5 min period changes in fD caused by 0.2–0.3 % disturbances in N. The decrease in N attained ~15 % (vs modeled 16 %).

Temperatures at 85 km around Earths poles in the summer can be so cold that small ice particles form. These particles can become charged and combined with turbulence at these altitudes they can influence the many electrons present. This can cause large radar echoes called Polar Mesospheric Summer Echoes. We use radio waves to heat these echoes on and off when the sun is close or below the horizon. This allows us to gain some insight into these ice particles and how the sun influences the echoes.

Solar wind Alfvén waves coupling to the dayside magnetosphere produced ionospheric density patches in the polar cap and modulated auroral electrojet currents that launched traveling ionospheric disturbances propagating in the mid latitudes. Ionospheric signatures of magnetic reconnection at the dayside magnetosphere, density patches in the polar cap, ionospheric currents and traveling ionospheric disturbances were observed by radars, ionosondes, ground magnetometers, and GPS receivers.

Poleward moving auroral forms (PMAFs) are specific types of aurora that are believed to be the signature of the connection of Earth's magnetic field to that of the sun. In this paper we discuss the evolution of PMAFs in regards to their auroral morphology as observed in all-sky camera images. We interpret different aspects of this evolution in terms of the connection dynamics between Earth's and the sun's magnetic fields. This sheds more light on the magnetic interaction between sun and Earth.

We observed three different wave structures in the earth’s upper atmosphere: a gravity wave in the mesosphere, the ionospheric disturbances, and the concentric wave structure in the ionosphere. We investigated these wave propagations by using airglow imaging and GNSS radio wave measurements. It is found that there was a gravity wave generation from the tropospheric convection spot. This is to report an observational evidence of gravity wave propagation from the troposphere to ionosphere.