Topside Ionosphere and Plasmasphere Modelling Using GNSS Radio Occultation and POD Data

A 3D-model approach has been developed to describe the electron density of the topside ionosphere and plasmasphere based on Global Navigation Satellite System (GNSS) measurements onboard low Earth orbit satellites. Electron density profiles derived from ionospheric Radio Occultation (RO) data are extrapolated to the upper ionosphere and plasmasphere based on a linear Vary-Chap function and Total Electron Content (TEC) measurements. A final update is then obtained by applying tomographic algorithms to the slant TEC measurements. Since the background specification is created with RO data, the proposed approach does not require using any external ionospheric/plasmaspheric model to adapt to the most recent data distributions. We assessed the model accuracy in 2013 and 2018 using independent TEC data, in situ electron density measurements, and ionosondes. A systematic better specification was obtained in comparison to NeQuick, with improvements around 15% in terms of electron density at 800 km, 26% at the top-most region (above 10,000 km) and 26% to 55% in terms of TEC, depending on the solar activity level. Our investigation shows that the developed model follows a known variation of electron density with respect to geographic/geomagnetic latitude, altitude, solar activity level, season, and local time, revealing the approach as a practical and useful tool for describing topside ionosphere and plasmasphere using satellite-based GNSS data.

The role of hypothalamic-pituitaryadrenal axis genes in individual variance of stress sensitivity

Целью настоящего исследования являлась оценка вклада 10 полиморфных локусов генов глюкокортикоидного (NR3C1) и минералокортикоидного (NR3C2) рецепторов, а также ген-средовых (G×E) взаимодействий в формирование межиндивидуальных различий в индивидуальных психологических свойствах у 1215 психически здоровых индивидов. Множественный регрессионный анализ выявил, что пренатальный уровень солнечной активности оказывал модулирующий эффект на ассоциацию функциональных полиморфных локусов rs56149945 (N363S) с показателями по шкале «настойчивость» (β = 1,21; р = 0,001) и rs41423247 в гене NR3C1 с индивидуальными различиями в уровне эмоциональной неустойчивости (β = -2,72; р = 0,005). The present study aimed to assess the main effects of ten polymorphisms of glucocorticoid (NR3C1) and mineralocorticoid receptor (NR3C2) genes together with gene-by-environment interactions on individual differences in personality traits in 1215 mentally healthy individuals aged 17-25 years. Multiple linear regression analysis demonstrated that prenatal solar activity level modulated the association of rs56149945 (N363S) with Persistence (β = 1.21; Р = 0.001) and rs41423247 in NR3C1 gene with emotional resistance to stress (β = -2.72; Р = 0.005).

Variability of ionospheric parameters by the Swarm satellites for different solar activity

<p>The use of satellite data allows us to study the variability of ionospheric plasma parameters globally without references to ground stations or receivers in different regions of the Earth. The Swarm mission, which was launched in 2014 and is still operational, allows us to investigate the effects of decreasing solar activity on the ionospheric variability. In our study we use the Swarm in-situ measurements of the electron density and derived parameters. This dataset provides characteristics of the plasma variability along the orbit and gives information on plasma density structures in the ionosphere in terms of their amplitudes, gradients and spatial scales. We analyze the variability of these parameters in the contexts of the northern and southern hemispheres, specific latitudinal regions, and the solar activity level. Understanding of the distribution of such parameters in the context of the solar activity level and selected ionospheric regions can have implications for the development of new satellite instruments and for the accuracy of GNSS precise positioning.</p>

Influence of tides on the ionospheric annual anomalies

<p>Through respectively adding June tides and December tides at the low boundary of GCITEM-IGGCAS model (Global Coupled Ionosphere-Thermosphere-Electrodynamics Model, Institute of Geology and Geophysics, Chinese Academy of Sciences), we simulate the influence of tides on the annual anomalies of the ionospheric electron density. The tides’ influence on the annual anomalies of the ionospheric electron density varies with latitude, altitude and solar activity level. Compared with the density driven by December tides, the June tides mainly increases the lower ionospheric electron density, and mainly decreases the electron density at higher ionosphere. In the low-latitude ionosphere, tide drives an additional equatorial ionization anomaly structure (EIA) at higher ionosphere in the relative difference of electron density, which suggests that tide affect the equatorial vertical <strong>E×B</strong> plasma drifts. Although the lower ionospheric annual anomalies driven by tides mainly increases with the increase of solar activity, the annual anomalies at higher ionosphere mainly decreases with solar activity.</p><p></p>

Sunspot observations by Charles Malapert during the period 1618–1626: a key data set to understand solar activity before the Maunder minimum

ABSTRACT A revision is presented of the sunspot observations made by Charles Malapert from 1618 to 1626, studying several documentary sources that include those observations. The revised accounting of the group numbers recorded by Malapert for that period shows new information unavailable in the current sunspot group data base. The average solar activity level calculated from these revised records of Malapert is by almost one-third greater than that calculated from his records included in the current group data base. Comparison of the sunspot observations made by Malapert and by other astronomers of that time with regard to the number of recorded groups and sunspot positions on the solar disc shows good agreement. Malapert reported that he only recorded one sunspot group in each sunspot drawing presented in Austriaca Sidera Heliocyclia (the documentary source that includes most of the sunspot records made by Malapert), although he sometimes observed several groups. Therefore, the sunspot counts obtained in this work on Malapert's sunspot observations represent the lower limit of the solar activity level corresponding to those records.

Solar rotational cycle in lightning activity in Japan during the 18–19th centuries

Thunderstorm and cloud activities sometimes show a 27-day period, and this has long been studied to uncover a possible important link to solar rotation. Because the 27-day variations in the solar forcing parameters such as solar ultraviolet and galactic cosmic rays become more prominent when the solar activity is high, it is expected that the signal of the 27-day period in meteorological phenomena may wax and wane according to the changes in the solar activity level. In this study, we examine in detail the intensity variations in the signal of the 27-day solar rotational period in thunder and lightning activity from the 18th to the 19th centuries based on 150-year-long records found in old diaries kept in Japan and discuss their relation with the solar activity levels. Such long records enable us to examine the signals of solar rotation at both high and low solar activity levels. We found that the signal of the solar rotational period in the thunder and lightning activity increases as the solar activity increases. In this study, we also discuss the possibility of the impact of the long-term climatological conditions on the signals of the 27-day period in thunder/lightning activities. Keywords. Meteorology and atmospheric dynamics (lightning)

Winter anomaly in NmF2 and TEC: when and where it can occur

For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (Nm F2) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in Nm F2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly.

Model of flare lightcurve profile observed in soft X-rays

We propose a new model for description of solar flare lightcurve profile observed in soft X-rays. The method assumes that single-peaked ‘regular’ flares seen in lightcurves can be fitted with the elementary time profile being a convolution of Gaussian and exponential functions. More complex, multi-peaked flares can be decomposed as a sum of elementary profiles. During flare lightcurve fitting process a linear background is determined as well. In our study we allow the background shape over the event to change linearly with time. Presented approach originally was dedicated to the soft X-ray small flares recorded by Polish spectrophotometer SphinX during the phase of very deep solar minimum of activity, between 23rd and 24th Solar Cycles. However, the method can and will be used to interpret the lightcurves as obtained by the other soft X-ray broad-band spectrometers at the time of both low and higher solar activity level. In the paper we introduce the model and present examples of fits to SphinX and GOES 1-8 Å channel observations as well.