Using the Beijing MST radar echo power observations collected during the period November 2011–May 2017, the structure and variability of the tropopause over Xianghe, China (39.75° N, 116.96° E) was presented. Our comparison results showed a good agreement between the radar and thermal tropopauses during all seasons. Whereas the consistency between the radar and dynamical tropopauses is poor during summer. Diurnal oscillation in tropopause height is commonly observed during all seasons.

Blanco-Cano et al. (2018) intended to find a type of transient event in the solar wind before the terrestrial bow shock using a special type of simulation. However, the simulation results cannot reproduce the main features of the event. Not only are the physical indicators missing from the simulation result, but the footprints and the signs of the event formation processes too. Based on the remarks described below, I am sure that the features in the simulations are not those type of events.

The fundamental mode of oscillations of the solar atmosphere, f-mode, plays an important role in solar physics. At an early stage of observing, it was found that its frequency is related to the wavelength by a ratio characteristic of waves on the surface of deep water. Subsequent observations revealed its inaccuracy. We derived waves with a different frequency-wavelength ratio and compared them with other possible waves of this type both in the solar and in the terrestrial atmosphere.

The Earth's radiation belts control the space environment often affecting the GPS signal propagation and satellite operations. Intense fluxes of energetic particles can penetrate even below the inner belt near the equator. We analyzed electron penetrations under geomagnetic quiet conditions and found in the solar wind an external driver caused that. Satellite observations prove that disturbance of the inner belt was associated with impact of plasma jets formed in the solar wind nearby the Earth.

Our research explores a new method for identifying where and when the magnetic field lines in Earth's magnetotail may change its topology through the reconnection process, during which a sudden release of magnetic energy can lead to the brightening of aurora, a process called substorm. Traditionally, the magnetic reconnection was often interpreted using a two-dimensional model, which however does not capture the intrinsically three-dimensional nature of reconnection physics, as we have revealed.

Higher TEC day-to-day variations during the daytime than nighttime for all the years were observed. The diurnal variation shows OBS-TEC rising rapidly from a minimum just before sunrise between 03:00–05:00 LT (~ 2 TECU) in 2011, 04:00–05:00 LT (~ 3 TECU) in 2012, 03:00–05:00 LT in 2013 (~ 3 TECU), and 03:00–05:00 LT in 2014 (~3 TECU). OBS-TEC is found to increase to a broad daytime maximum between 00:12 LT 354–00:16 LT for all years before falling to a minimum after sunset.

Observations of flapping current sheet in the magnetotail are presented to reveal their intrinsic excitation mechanism induced by alternating north-south asymmetric ion populations in the sheet center. The results suggest that nonadiabatic ions play a substantial role to determine current sheet dynamics, both its bulk mechanical instability and current profiles.

The interplanetary magnetic field is a consequence of the solar magnetic field and the solar wind. Different magnetic field models exist in literature that allow to better understand how the solar field extends throughout the solar system. We highlight different aspects of these different interplanetary magnetic field models and discuss possible applications. Verification of these models will become possible using data from the Parker Solar Probe and Bepi-Colombo space mission.

We observe the planetary and gravity wave activity in the vertical profile of ozone at the mid- European ozonosonde stations The performance of the used detection method is satisfactory. There are differences in the following characteristics of the structure caused by the planetary and gravity wave: the annual variation, the size, the vertical distribution and trend. The results are influenced by the ozonosonde vertical resolution only for small and medium structures.

Occasional deviations in density and magnetic power spectral densities in an intermediate frequency range are interpreted as ion response to the Kolmogorov turbulent velocity spectrum.

Receivers and Satellites Differential Code Biases (DCBs) are one of the main error sources in estimating precise Global Ionosphere Maps (GIMs) from Global Positioning Systems (GPS) data. This paper introduces a mathematical model for estimating satellites & receivers DCBs from A GPS network written under MATLAB environment. Our code was tested and compared with Ionosphere Associated Analysis Centers (IAAC) and other researchers' codes results. The results shows an improvement for estimated DCBs.

This study is concerning of the postmidnight ionospheric irregularities observed during low solar activity conditions. We analyze data from digisondes and optical imaging systems located at equatorial region over Brazil. The results show that they occur under unfavorable and unexpected conditions. This work can be useful for Space Weather forecasting during low solar activity.