Recent  

To study long-term trends in the mesosphere and lower thermosphere (70–100 km) we established two summer length definitions and analyzed the variability over the years (2004–2020). After the analysis, we found significant trends in the summer beginning of one definition. Furthermore, we were able to extend one of the time series up to 31 years, and we obtained evidence of non-uniform trends and periodicities similar to those known for quasi-biennial oscillation and El Niño-southern oscillation.

This article is about using remote sensing data to estimate the date and magnitude of the impending earthquakes. An earthquake can also affect the environment. Damage to the environment can destroy and lose lives and be more dangerous than earthquakes. The damage sustained by earthquakes is due to the secondary effects of man-made materials on the environment. Water pipes are broken and the ground is flooded, and gas, electricity and scattered fuel lines cause fires.

We developed a new approach for validation the numerical models of electromagnetic wave propagation in the Earth-ionosphere waveguide. We compared the parameters of the waveguide (i.e., characteristic electric and magnetic altitudes, resonance frequencies, phase velocity and attenuation rate) obtained from numerical model with correspondent analytical calculations. We tested such validation for various conductivity profiles and find good agreement between analytical and numerical results.

A rare gravity wave event was observed on the night of 25 April 2017 over northern Germany. An all-sky airglow imager recorded an upward propagating wave at different altitudes in mesosphere with a prominent wave front above 91 km and faintly observed below. Based on wind and satellite borne temperature profiles close to the event location, we have found the presence of a leaky thermal duct layer in 85–91 km. The appearance of this duct layer caused the wave amplitudes to diminish below 91 km.

Although the 1991 eruption of Mt Pinatubo had a severe impact on earths climate, the effect of this event on the mesosphere is not well understood. We investigated satellite-borne temperature measurements from the HALOE instrument and found indications that a positive temperature anomaly is present in the tropical upper mesosphere at the beginning of the HALOE time series, which may be related to the eruption of Mt. Pinatubo.

We develop an automatic procedure based on the two criteria of the Wang-Pan method, and it consists of three parts: selection of the potentially high Alfvénic fluctuation events, evaluation of the OOLs, and determination of the zero offset. We test our automatic procedure by using three months of the partially calibrated data measured by VEX FGM, and find that our automatic procedure is successful to achieve as good results as the Davis-Smith method.

We characterised the diurnal VLF amplitude into five metrics – mean amplitude before sunrise (MBSR), midday amplitude peak (MDP), mean amplitude after sunset (MASS), sunrise terminator (SRT) and sunset terminator (SST). We analysed their trend in variations of the signal during geomagnetic storms and found that the signal exhibit significant dipping due to the storms. Responses of high frequency radio pulses also showed evidence of markedly disturbed ionosphere over the signal paths.

Here we propose a new method to estimate the loss of atmosphere by ion escape from unmagnetized planets that combines observations and models. The proposed method allow us to estimate the ionospheric ion escape rate from one bow shock crossing using ion and magnetic field observations. This enables studies of how escape depend on different parameters, and also escape rates during extreme solar wind conditions, applicable to studies of escape in the early solar system, and at exoplanets.

It has long been known that particles get accelerated close to the speed of light in the near Earth's space environment. Research in the last decades have also clarified what processes and waves are responsible for the acceleration of particles. However, it is difficult to quantify the scale of the impact of various processes competing with one another. In this study we present a methodology to quantify the impact waves can have on energetic particles.

Our model calculations indicate that meteoric smoke particles (MSP) influence both the magnitude and shape of the electron temperature during artificial heating. Others have found that current theoretical models most likely overestimate heating in the D-region compared to observations. In a future study, we will compare of our results to observations of the electron temperature during heating to investigate if the presence of MSP can explain the discrepancy between model and observations.