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.

We are presenting: (1) K–H vortices in direct response to the northward turning of IMF without pre-existing denser boundary layer to facilitate the instability; (2) substantial solar wind transport into magnetosphere caused by the K–H vortices, involving both ion and electron fluxes; (3)typical portaits of the ion and electron fluxes in the region of plasma tranport. The unique characteristics may reshape our understanding of the K–H vortices and tranport process.

This study presents the observation of 5 gravity waves detected over São João do Cariri, Brazil. Gravity waves which results from the displacement of the atmospheric fluids strongly influences fluid transport and turbulence in the upper atmosphere. Using OH airglow images, we spotted some gravity waves, obtained their characteristics, and employed the reverse ray-tracing technique to identify their sources which were traced to the convection processes in the Inter Tropical Convergence Zone.

The terrestrial ion transport was synthesised, with stress on high-latitude polar region and the inner magnetosphere where Custer improved the knowledge. After classifying the outflow (cold refilling, cold supersonic flow, and suprathermal/hot outflow), ion dynamics in the inner magnetosphere was summarized. With a careful consideration of O⁺ loss process, more than half the outflow is finally lost to the space, reaching high enough escape rate to even influence the evolution of the biosphere.

Oxygen ions are an important element in the mass and energy transport in the magnetospheric dynamic process during intense substorms (AE > 500 nT). We did this work to better understand the O⁺ at the dusk flank magnetopause varying with solar wind conditions and AE index during intense substorm. The results show the O⁺ abundance at the dusk flank magnetopause have a corresponding relation with that in the duskside near Earth plasma sheet and the enhancement of O⁺ may affect the reconnection at MP.

The mirror mode starts as a zero frequency ion fluid instability and saturates quasi-linearly at very low magnetic level, while forming extended magnetic bubbles which trap the electron component into an adiabatic bounce motion. Near its trapped mirror points electrons form pairs which behave coherently. Their diamagnetic effect increases the mirror amplitude far above its quasilinear level. The abolute achievable amplitude limit is estimated.

This study correlates ionospheric parameters with the integrated solar radiation for an analysis of the delayed ionospheric response in order to confirm previous studies on the delay and to further specify variations of the delay (seasonal and spatial). Results also indicate the dependence on the geomagnetic activity as well as on the 11-year solar cycle. The results are important for the understanding of ionospheric processes and could be used for the validation of ionospheric models.

In a context of climate change, the wind energy sector has seen a very sharp growth requiring accurate forecasts. Air density is a key variable in the wind energy modeling as it can make the power output varies by almost 20 %. In this paper, a numerically low-cost method is evaluated. This method improves the wind energy modeling by more than 15 % and by almost 40 % when the atmospheric conditions are far from the standards atmospheric conditions used to produce the wind turbine power curve.

To correct the NRLMSISE-00, more than 15 years of satellite atmospheric density data is used at 20–100 km. Based on the differences between model and observation data, a spatiotemporal correction function is proposed. The correction function has a significant improvment to the model. It can provide more reliable density data for scientific research and engineering fields.

In this paper, a quasi-empirical convective eddy diffusivity parameterizations for a coastal site are obtained. In the derivation was used Taylor's theory of statistical diffusion and sonic anemometer observations collected at 11 levels on a 140-m high tower in a convective planetary boundary layer. The test of the derived coefficients was solved by solving the equation of diffusion-advection by the Fractional Step/Locally One-Dimensional (LOD) methods.