Последние статьи в Annales Geophysicae

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Combined list of the recent articles of the journal Annales Geophysicae and the recent discussion forum Annales Geophysicae Discussions
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Impact of gravity wave drag on the thermospheric circulation: implementation of a nonlinear gravity wave parameterization in a whole-atmosphere model

Thu, 10/17/2019 - 16:26
Impact of gravity wave drag on the thermospheric circulation: implementation of a nonlinear gravity wave parameterization in a whole-atmosphere model
Yasunobu Miyoshi and Erdal Yiğit
Ann. Geophys., 37, 955–969, https://doi.org/10.5194/angeo-37-955-2019, 2019
Our numerical simulation shows that the drag due to the dissipation and/or breaking of the gravity wave plays an important role in the general circulation in the thermosphere. This means that the parameterization for the gravity wave drag is necessary for numerical simulation in the thermosphere.
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The fate of O+ ions observed in the plasma mantle and cusp: particle tracing modelling and Cluster observations

Wed, 10/16/2019 - 16:26
The fate of O+ ions observed in the plasma mantle and cusp: particle tracing modelling and Cluster observations
Audrey Schillings, Herbert Gunell, Hans Nilsson, Alexandre De Spiegeleer, Yusuke Ebihara, Lars G. Westerberg, Masatoshi Yamauchi, and Rikard Slapak
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-146,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
The Earth's atmosphere is constantly losing molecules and charged particles, amongst them oxygen ions or O+. Quantifying this loss provides information about the evolution of the atmosphere on geological timescales. In this study, we investigate the final destination of O+ observed with Cluster satellites in a high-altitude magnetospheric region (plasma mantle) by tracing the particles forward in time using simulations. We find that approximately 96 % of O+ escape the Earth's magnetosphere.
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Nonlinear forcing mechanisms of the migrating terdiurnal solar tide and their impact on the zonal mean circulation

Thu, 10/10/2019 - 16:26
Nonlinear forcing mechanisms of the migrating terdiurnal solar tide and their impact on the zonal mean circulation
Friederike Lilienthal and Christoph Jacobi
Ann. Geophys., 37, 943–953, https://doi.org/10.5194/angeo-37-943-2019, 2019
We analyzed the forcing mechanisms of the migrating terdiurnal solar tide in the middle atmosphere, focusing the impact on the zonal mean circulation. We show that the primary solar forcing is the most dominant one but secondary wave–wave interactions also contribute in the lower thermosphere region. We further demonstrate that small-scale gravity waves can strongly and irregularly influence the amplitude of the terdiurnal tide as well as the background circulation in the thermosphere.
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Strong southward and northward currents observed in the inner plasma sheet

Thu, 10/10/2019 - 16:26
Strong southward and northward currents observed in the inner plasma sheet
Yan-Yan Yang, Chao Shen, and Yong Ji
Ann. Geophys., 37, 931–941, https://doi.org/10.5194/angeo-37-931-2019, 2019
Previous studies show that the ring current (RC) and field-aligned currents (FACs) are the dominant currents in the inner magnetosphere. However, through two large storm events observed by Cluster, we find new strong southward and northward currents in the latitudinal region from 10° N to 30° N. Theoretical analysis indicates that these currents originated from the fluctuation of magnetic field lines during strong geomagnetic storms.
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Wavelet analysis of the magnetotail response to solar wind fluctuations during HILDCAA events

Wed, 10/09/2019 - 16:26
Wavelet analysis of the magnetotail response to solar wind fluctuations during HILDCAA events
Adriane Marques de Souza Franco, Ezequiel Echer, and Mauricio José Alves Bolzan
Ann. Geophys., 37, 919–929, https://doi.org/10.5194/angeo-37-919-2019, 2019
The wavelet transform was employed in nine HILDCAA events for intervals in which the Cluster crossed the magnetotail in order to identify the most energetic periods of these events in the magnetotail. It was seen that 76 % of the periods identified are ≤4 h. Using the cross wavelet analysis technique between Bz–IMF components and the Bx geomagnetic components, it was identified that the coupling of energy is stronger in periods between 2 and 4 h, which are typical substorm periods.
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Evaluation of Possible Corrosion Enhacement Due to Telluric Currents: Case Study for Brazilian Pipeline

Mon, 10/07/2019 - 16:26
Evaluation of Possible Corrosion Enhacement Due to Telluric Currents: Case Study for Brazilian Pipeline
Joyrles Fernandes de Moraes, Igo Paulino, Livia Alves, and Clezio Marcos Dinardini
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-132,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Using the distributed source line transmission (DSLT) theory and magnetometers data, induced electrical field was calculated for the first time in a Brazilian pipeline. The corrosion rate was also evaluated using the Gummow's methodology. With different terminating impedance, the pipeline was out the safe range of operation, even for low terminating impedance. The corrosion rate was significant for strong geomagnetic storms, however it was not above the acceptable limit.
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Migrating and Non-Migrating Tides Observed in the Stratosphere from FORMOSAT-3/COSMIC Temperature Retrievals

Tue, 10/01/2019 - 16:26
Migrating and Non-Migrating Tides Observed in the Stratosphere from FORMOSAT-3/COSMIC Temperature Retrievals
Uma Das, William Ward, Chen Jeih Pan, and Sanat Kumar Das
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-140,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Temperatures obtained from FORMOSAT-3/COSMIC observations in the stratosphere are analysed for tidal variations. It is seen that the non-migrating tides are not very significant in the high latitude winter stratosphere. It is shown in this study that the observed amplitudes of these tides are most probably a result of aliasing and they are not geophysical in nature. Thus, the process through which it was believed that they are produced (non-linear interactions) seems to be unimportant.
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BD-IES Observation of Multi-Period Electron Flux Modulation Caused by Localized Ultra-Low Frequency Waves

Fri, 09/27/2019 - 16:26
BD-IES Observation of Multi-Period Electron Flux Modulation Caused by Localized Ultra-Low Frequency Waves
Xingran Chen, Qiugang Zong, Hong Zou, Xuzhi Zhou, Li Li, Yixin Hao, and Yongfu Wang
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-139,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
We present a new in-situ observation of energetic electron in space obtained by a newly available particle detector. In view of the characteristic signatures in the particle flux, we attribute the observational features to the drift-resonance wave-particle interaction between energetic electrons and multiple localized ULF waves. The scenario is substantiate by a numerical calculation based on the revised drift-resonance theory which reproduced the observed particle signatures.
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Multi-point galactic cosmic ray measurements between 1 and 4.5 AU over a full solar cycle

Wed, 09/25/2019 - 16:26
Multi-point galactic cosmic ray measurements between 1 and 4.5 AU over a full solar cycle
Thomas Honig, Olivier G. Witasse, Hugh Evans, Petteri Nieminen, Erik Kuulkers, Matt G. G. T. Taylor, Bernd Heber, Jingnan Guo, and Beatriz Sánchez-Cano
Ann. Geophys., 37, 903–918, https://doi.org/10.5194/angeo-37-903-2019, 2019
We analysed data from radiation monitors aboard different spacecraft such as Rosetta and Integral. From the data, we extracted the evolution of galactic cosmic rays as a function of time (over a full solar cycle) and position (from 1 to 4.5 AU). In the main results, we confirm the overall evolution (anti-correlation) of the fluxes with respect to the solar activity. We found a surprising result, which is a decrease in the flux of galactic cosmic rays around comet 67P.
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Polar substorm on 7 December 2015: pre-onset phenomena and features of auroral breakup

Wed, 09/25/2019 - 16:26
Polar substorm on 7 December 2015: pre-onset phenomena and features of auroral breakup
Vladimir V. Safargaleev, Alexander E. Kozlovsky, and Valery M. Mitrofanov
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-118,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)
Comprehensive analysis of a moderate substorm was performed with using optical observations inside the auroral oval and in the polar cap, combined with data from satellites, radars, and ground magnetometers. The onset took place near the poleward boundary of the auroral oval that is not typical for classical substorms. Data set fits to the near-tail current disruption scenario of the substorm onset. The role of the 15-min oscillations in IMF Bz component in the substorm initiation is discussed.
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Low-frequency magnetic variations at the high-β Earth bow shock

Tue, 09/24/2019 - 16:26
Low-frequency magnetic variations at the high-β Earth bow shock
Anatoli A. Petrukovich, Olga M. Chugunova, and Pavel I. Shustov
Ann. Geophys., 37, 877–889, https://doi.org/10.5194/angeo-37-877-2019, 2019
Earth's bow shock in solar wind with high thermal and low magnetic pressure is a rare phenomenon. However, such an object is ubiquitous in astrophysical plasmas. We surveyed statistics of such shock observations since 1995. About 100 crossings were initially identified. In this report 22 crossings from the Cluster project were studied using multipoint analysis, which allowed for the determination of the spatial scales of the shock transition and of the dominant magnetic variations
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Climatologies and long-term changes in mesospheric wind and wave measurements based on radar observations at high and mid latitudes

Tue, 09/24/2019 - 16:26
Climatologies and long-term changes in mesospheric wind and wave measurements based on radar observations at high and mid latitudes
Sven Wilhelm, Gunter Stober, and Peter Brown
Ann. Geophys., 37, 851–875, https://doi.org/10.5194/angeo-37-851-2019, 2019
We report on long-term observations of atmospheric parameters in the mesosphere and lower thermosphere made over the last 2 decades for the northern-latitude locations of Andenes, Juliusruh, and Tavistock. The observations are based on meteor wind measurements and further include the long-term variability of winds, tides, and the kinetic energy of gravity waves and planetary waves. Furthermore, the influence on an 11-year oscillation on the winds and tides is presented.
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On modelling the kinematics and evolutionary properties of pressure-pulse-driven impulsive solar jets

Tue, 09/24/2019 - 16:26
On modelling the kinematics and evolutionary properties of pressure-pulse-driven impulsive solar jets
Balveer Singh, Kushagra Sharma, and Abhishek K. Srivastava
Ann. Geophys., 37, 891–902, https://doi.org/10.5194/angeo-37-891-2019, 2019
Solar jets driven by heat or pressure pulses at their footpoints in the photosphere transfer energy and mass in to the corona. These jets energize the coronal part of the atmosphere with collimated plasma, similar to the fluid filled in a pipe. Understanding the physical drivers of such jets is of great significance to study the plasma in confined magnetic fields. The modelled jets in our paper allow for the study of the evolution of chromospheric plasma and support many existing observations.
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Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes

Mon, 09/23/2019 - 16:26
Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes
Alexander Rozhnoi, Maria Solovieva, Viktor Fedun, Peter Gallagher, Joseph McCauley, Mohammed Y. Boudjada, Sergiy Shelyag, and Hans U. Eichelberger
Ann. Geophys., 37, 843–850, https://doi.org/10.5194/angeo-37-843-2019, 2019

In this paper we analysed sudden phase anomalies (SPAs) of VLF–LF signals recorded at Graz (Austria), Birr (Ireland) and Moscow (Russia) stations during two strong solar flares in September 2017. The first X-class 9.3 flare occurred on 6 September at 12:02 UT, and the second X-class 8.2 flare was observed on 10 September 2017 at 16:06 UT. Data from seven transmitters in a frequency range between 20 and 45 kHz are used for the analysis. The SPAs were observed in all middle-latitude paths (differently orientated) with path lengths from 350 to 7000 km. Solar X-ray burst data were taken from GOES satellite observations in the wavelength band of 0.05–0.4 nm. It was found that (i) the amplitude of SPAs in different paths varies from 10 to 282∘, and (ii) the correlation between the amplitudes of SPAs, the lengths of paths and the signal frequency is weak. The change in effective height of reflection due to lowering of the reflecting layer during the flares was found to be about 12 km for the first event and about 9 km for the second event. Spectral analysis of the X-ray and LF data, filtered in the range between 5 s and 16 min, showed that the LF signal spectra are very similar to X-ray spectra. Maxima of both X-ray and LF spectra are in 2–16 min interval.

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Multi-channel coupling of decay instability in three-dimensional low-beta plasma

Fri, 09/20/2019 - 16:26
Multi-channel coupling of decay instability in three-dimensional low-beta plasma
Horia Comişel, Yasuhito Narita, and Uwe Motschmann
Ann. Geophys., 37, 835–842, https://doi.org/10.5194/angeo-37-835-2019, 2019
Here we present a scenario that the decay of a field-aligned Alfvén wave can occur simultaneously at various angles to the mean magnetic field, generating a number of second-order fluctuations or waves (after the pump wave as the first-order fluctuation). We refer to the simultaneous decay as multi-channel couplings following the notion in scattering theory. Our goal is to study the hypothesis of the multi-channel coupling by running a three-dimensional hybrid plasma simulation.
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Scaling laws in Hall inertial-range turbulence

Thu, 09/19/2019 - 16:26
Scaling laws in Hall inertial-range turbulence
Yasuhito Narita, Wolfgang Baumjohann, and Rudolf A. Treumann
Ann. Geophys., 37, 825–834, https://doi.org/10.5194/angeo-37-825-2019, 2019
Scaling laws and energy spectra for the electric field, magnetic field, flow velocity, and density are theoretically derived for small-scale turbulence in space plasma on which the electrons behave as a fluid but the ions more as individual particles due to the difference in the mass (the Hall effect). Our theoretical model offers an explanation for the small-scale turbulence spectra measured in near-Earth space.
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Excitation of chorus with small wave normal angles due to beam pulse amplifier (BPA) mechanism in density ducts

Wed, 09/18/2019 - 16:26
Excitation of chorus with small wave normal angles due to beam pulse amplifier (BPA) mechanism in density ducts
Peter A. Bespalov and Olga N. Savina
Ann. Geophys., 37, 819–824, https://doi.org/10.5194/angeo-37-819-2019, 2019
The paper discusses a problem concerned with the excitation of chorus with small wave normal angles along the external magnetic field in the magnetosphere. We examine the realisation of the beam pulse amplifier mechanism of chorus excitation without strong anisotropy of the plasma particle distribution function in the density ducts with refractive reflection. It is shown that in the ducts, discrete spectral elements of chorus can be excited at close to half of the electron cyclotron frequency.
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Intercomparison of FY-3 and AIRS Gravity Wave Parameter Extraction Based on Three Methods

Wed, 09/18/2019 - 16:26
Intercomparison of FY-3 and AIRS Gravity Wave Parameter Extraction Based on Three Methods
Shujie Chang, Zheng Sheng, Wei Ge, Wei Zhang, Yang He, and Zhixian Luo
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-130,2019
Manuscript under review for ANGEO (discussion: open, 4 comments)
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.
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Localized TEC enhancements in the Southern Hemisphere

Wed, 09/18/2019 - 16:26
Localized TEC enhancements in the Southern Hemisphere
Ilya K. Edemskiy
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-124,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)
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.
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Ionospheric Plasma Density Measurements by Swarm Langmuir Probes: Limitations and possible Corrections

Wed, 09/18/2019 - 16:26
Ionospheric Plasma Density Measurements by Swarm Langmuir Probes: Limitations and possible Corrections
Piero Diego, Igino Coco, Igor Bertello, Maurizio Candidi, and Pietro Ubertini
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-136,2019
Manuscript under review for ANGEO (discussion: open, 9 comments)
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.
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