Two types of temperature profile products from the FY-3 (FengYun-3) satellite system, using GNOS and VASS, together with AIRS operational Level 2 data, are used to compare and analyze gravity wave parameters. The advantages and disadvantages of these three types of temperature profile data for gravity wave parameter extraction are determined, based on three extraction methods: vertical sliding average, double-filter and single-filter.

The paper investigates feature in Southern hemisphere ionosphere, which is observed near midday in a form of localized enhancement of electron density. Being discovered in global ionospheric maps enhancements were observed via in-situ measurements of electron concentration as well. The probability of its detection is maximal during autumn-winter period and seems not to be directly dependent on geomagnetic indices and solar wind parameters.

In-situ measurements validation is always a delicate matter of study until data are collected by a single mission. In case of different missions operating almost in the same environment (i.e. latitude, altitude, local time) it is of fundamental importance the detection of instrumental setting and algorithms to provide the best accordance among measurements. The present work aims to validate both Swarm and CSES plasma density measures for the improvements of the ionospheric models development.

We investigate the magnetopause stability and mixing by a new 3fluid model aimed at reproducing at best the system configuration obtained directly from satellite data. This "realistic" model is a basic starting point for numerical simulations. The realistic 3fluid equilibrium presented in this paper should allow for a step further and could be applied to other experimental cases in the future. MMS DATA AVAILABLE AT: MMS data server: https://lasp.colorado.edu/mms/sdc/public/about/browse-wrapper.

The plasma bubbles and blobs were recorded on two successive days. The interesting is that one of the event occured in a quiet day, and the other in the main phase of a storm. The latitudinal variations of electron density at low- and middle ionosphere were used to analyze the physical factors leading to the variations in the F region and the occurrence of plasma bubbles and blobs. The work would help to understand the dominant factor accounting for the day-to-day occurrence of irregularities.

This is the first survey of pulsating aurora which is differentiated by type. Pulsating aurora is found to be a nearly ubiquitous early morning phenomenon, and it is almost entirely lacking persistent structuring before midnight. Long-lived patches which are known to move with convection primarily appear after midnight. These patches are a less common form of pulsating aurora and are found to originate from the inner magnetosphere, in agreement with past observations of their source region.

Observations of ionospheric plasma density, in the northern polar cap, investigated the boundary of regions containing much lower than background plasma density. Similar regions containing higher than background density have been linked to fluctuations of phase and amplitude in radio waves traversing the density gradient at their boundary. These fluctuations were absent through the density gradient at the lower than background regions showing a minimum of both density and gradient are required.

In order to prepare for the usage of cruise phase data from BepiColombo to study magnetic structures in the solar wind we have turned to Messenger cruise phase data between the Earth and Mercury. These structures are characterized by a decrease in the magnetic field created by a temperature asymmetry. We find that their occurrence rate decreases outward from Mercury, and that they look different outside of Venus's orbit as inside.

In this paper we have used Cluster EDI data in in combination with the CODIF cusp dataset from Slapak et al. (2017), to obtain parallel and convection velocities for oxygen ions. 69 % of total oxygen outflow from the high altitude cusps escape the magnetosphere on average. 50 % escape tailward beyond distant the X-line. The oxygen capture-versus-escape ratio is highly dependent on geomagnetic conditions. During active conditions, the majority of oxygen outflow is convected to plasma sheet.

Field line dipolarization at geosynchronous orbit can be regarded as increase of curvature radius of field lines in association with the combined effects of BBFs, Ballooning instability, and slow magnetoacoustic wave. Change of curvature radius created Bostrom type current system in ionosphere. These are new scenarios describing field line dipolarization and associated magnetosphere-ionosphere coupling and may resolve controversies to some extent in substorm onset scenario.

Here is presented the investigation of gravity waves (GWs) properties in the low ionosphere using very low frequency (VLF) radio signals. The VLF technique showed to be a powerful tool to obtain the wave period and duration of GW events in the low ionosphere, and can be used independent of sky conditions, during daytime and year-round, which is an advantage in comparison with airglow all-sky imagers.

A special EPB event, which emerged near dawn and kept developing after sunrise, was simultaneously observed by an all-sky imager and the GNSS network. The observed EPBs showed westward drifts. These characteristics are different from post-sunset EPBs. Those EPBs occurred in the recovery phase of a geomagnetic storm, which could play a key role in initializing their developments. These results provide a new perspective of the EPBs that enriches our knowledge of ionospheric irregularity.

The interaction between the Earth's environment and the electrically charged gas known as the solar wind is highly complex and has been under study for decades. We use a universal principle of physics – the relativity principle – to gain physical insight into this interaction. We apply this principle to physical processes that occur during geomagnetic storms. We clarify how the solar wind ultimately causes currents to flow between the Earth's upper atmosphere and space.

The purpose of this paper is to show how atmospheric dynamics behave during the occurrence of ozone-hole inflow events in Antarctica, especially in mid-latitude regions, such as southern Brazil, for 12 years of observation. The results showed that most of the events occur after the frontal systems pass through mid-latitude regions, highlighting the importance of this study for the southern region of Brazil. This work was developed by the UFSM Graduate Program in Meteorology.

The additional transfer of momentum and energy induced by locally breaking gravity wave hotspots in the lower stratosphere may lead to a destabilization of the polar vortex, which is strongly depending on the position of the hotspot. The simulations with a global circulation model show that hotspots located above Eurasia cause a total decrease in the stationary planetary wave (SPW) activity, while the impact of hotspots located in North America mostly increase the SPW activity.

The aim of this study is to bring local variabilities in a global context. To qualitatively study the impact of global waves on local measurements in winter, we combine local lidar measurements with global MERRA-2 reanalysis data. Our results show that about 97 % of the local day-to-day variability can be explained by the variability of waves with zonal wavenumbers 1, 2 and 3. Thus locally measured effects which are not based on global wave variability can be much better investigated.

The structure and medium-scale dynamics of the Earth's bow shock, and in particular how charged solar wind particles are sometimes reflected by it, are studied in order to better understand space weather effects. We use advanced supercomputer simulations to model the shock and particles. We find that the thickness of the shock depends on solar wind conditions, but has also small-scale variations. Charged particle reflection is shown to be more affected by magnetic fields than this thickness.

The Earth's polar upper atmosphere changes along with the magnetic field, other parts of the atmosphere, and the Sun. When studying these changes, knowing the polar region the data comes from is vital, since different processes dominate the area where the aurora are and poleward of the aurora (the polar cap). The boundary between these areas is hard to find, so this study used a different boundary and figured out how they are related. Future studies can now find their polar region more easily.

An unique stratospheric balloon-borne observation of noctilucent clouds (NLC) was performed on the night of 5–6 July 2018. A sounding balloon, carrying the NLC camera, reached 20.4 km altitude. NLC were observed from the stratosphere at large scales (100–1500 km) for the first time. Propagations of gravity waves of various scales have been registered. This experiment is rather simple and can be reproduced by broad geoscience community and amateurs, providing a new technique in NLC observations.

Comparisons were made of ground-based ionosonde (a type of radar) observations of the ionosphere and satellite-based observations of auroral far-ultraviolet emissions to determine whether a remote sensing algorithm for determining auroral ionospheric electron densities from far-ultraviolet emissions was biased by the presence of proton precipitation, and it was found that there was no such bias.

In this work, we studied the HILDCAAs disturbance time effects in the TEC analyzing local time and seasonal dependences, and the influences of the solar wind velocity to a sample of ten intervals occurred in 2015 and 2016. The main results show great variability on the hourly distribution of the dTEC between one interval and another, seasonal behavior different from that presented by geomagnetic storms and the interesting no relation between the dTEC disturbances and the magnitude of the HSS.

It is presented two historical aurora catalogs for Anatolia and Middle East regions at various dates to understand the past solar activity and possible physical mechanism using historical texts, chronicles and other auroral records. An unusually high auroral activity during the years around 1100 in Anatolia and Middle East is quite consistent with the past solar variability, geomagnetic field intensity and planetary climatic changes drastically impacting on the economy and human events.

Propagating characteristics of early morning precipitation (EMP) are more prominent, which signifies EMP in association with extreme precipitation events. The flat phase distribution of EMP events suggests that the timing of coastal precipitation is not necessarily locked to the phase of land/sea-breezes, thus, allowing precipitation to occur more randomly. This implies that, even for 24-hour lead time,probabilistic forecast maybe necessary to assess the hazard of heavy precipitation.

The empirical orthogonal function (EOF) decomposition was utilized to analyze the similarities and differences of the spatiotemporal characteristics between the GIM-TEC and IRI-TEC at a global scale. We combined the IRI-TEC and GIM-TEC data to form a whole data set for EOF decomposition and compared the two data sets. Results show that the daily averaged solar forcing and interhemispheric asymmetry components were the main factors for the deviation between the IRI-2016 and GIM TECs.

Jets of solar wind plasma commonly hit the Earth's magnetosphere. Using data from the four Magnetospheric Multiscale (MMS) spacecraft, we show statistically that within jets the magnetic field is more aligned with the plasma flow direction than outside of these jets. Our study confirms prior simulation results, but also shows that the average effect is moderate. The jets' magnetic field is important with respect to their impact on space weather.

Interannual variabilities of the zonal mean wind and temperature related to the Rossby wave forcing in the winter stratosphere of the Southern Hemisphere are studied using 38-year reanalysis data. Correlation of the mean fields to the wave forcing is extended to the subtropics of the Northern Hemisphere. This interhemispheric link is caused by the wave forcing which reduces the meridional gradient of the angular momentum and drives the meridional circulation over the equator in the stratosphere.