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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Plasma transport into the duskside magnetopause caused by Kelvin–Helmholtz vortices in response to the northward turning of the interplanetary magnetic field observed by THEMIS

Fri, 07/19/2019 - 16:32
Plasma transport into the duskside magnetopause caused by Kelvin–Helmholtz vortices in response to the northward turning of the interplanetary magnetic field observed by THEMIS
Guang Qing Yan, George K. Parks, Chun Lin Cai, Tao Chen, James P. McFadden, and Yong Ren
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-103,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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On the evaluation of the phase relation between temperature and wind tides based on ground-based measurements and reanalysis data in the middle atmosphere

Thu, 07/18/2019 - 16:32
On the evaluation of the phase relation between temperature and wind tides based on ground-based measurements and reanalysis data in the middle atmosphere
Kathrin Baumgarten and Gunter Stober
Ann. Geophys., 37, 581-602, https://doi.org/10.5194/angeo-37-581-2019, 2019
The paper presents the variability in thermal tides in the middle atmosphere from temperature observations as well as from horizontal wind data using a new diagnostic approach which takes into account a possible intermittency of tides. The data are analyzed from a local as well as from a global perspective to distinguish between different tidal modes. Surprisingly, there are dominating tidal modes, which are seen in the local data, and a phase relation between temperature and winds is evaluated.
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Estimation of westward auroral electrojet current with magnetometer chain data

Tue, 07/16/2019 - 16:32
Estimation of westward auroral electrojet current with magnetometer chain data
Marina A. Evdokimova and Anatoli A. Petrukovich
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-96,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)

We investigate one-dimensional models of westward substorm electrojet, using magnetic field observations along a meridian chain. We review two linear models of Kotikov et al. (1987) and Popov et al. (2001) with the large number of elementary currents at fixed positions. They can be applied to a magnetometer chain with many magnetic stations. A new nonlinear method with one current element is designed for the cases with small number of stations. We illustrate performance of these methods using data from IMAGE and Yamal Peninsula stations. Several corrective measures are proposed to account for unphysical solutions or local extrema of the optimized functions. We also advertize a generic maximum likelyhood approach to a problem, usable for any empiric model.

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Dust observations with antenna measurements and its prospects for observations with Parker Solar Probe and Solar Orbiter

Mon, 07/15/2019 - 16:32
Dust observations with antenna measurements and its prospects for observations with Parker Solar Probe and Solar Orbiter
Ingrid Mann, Libor Nouzák, Jakub Vaverka, Tarjei Antonsen, Åshild Fredriksen, Karine Issautier, David Malaspina, Nicole Meyer-Vernet, Jiří Pavlů, Zoltan Sternovsky, Joan Stude, Shengyi Ye, and Arnaud Zaslavsky
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-94,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)

The electric and magnetic field instrument suite FIELDS on board the NASA Parker Solar Probe and the radio and plasma waves instrument RPWS on the ESA Solar Orbiter mission that explore the inner heliosphere are sensitive to signals generated by dust impacts. Dust impacts were observed using electric field antennas on spacecraft since the 1980s and the method was recently used with a number of space missions to derive dust fluxes. Here, we consider the details of dust impacts, subsequent development of the impact generated plasma and how it produces the measured signals. We describe empirical approaches to characterise the signals and compare to a qualitative discussion of laboratory simulations to predict signal shapes for spacecraft measurements in the inner solar system. While the amount of charge production from a dust impact will be higher near the sun than observed in the interplanetary medium before, the amplitude of pulses will be lower because of the different recovery behaviour that varies with the plasma environment. The photocurrent, that is expected to be higher near the Sun, is found to have moderate influence on the spacecraft potential.

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Investigation of sources of gravity waves observed in the Brazilian Equatorial region on 08 April 2005

Mon, 07/15/2019 - 16:32
Investigation of sources of gravity waves observed in the Brazilian Equatorial region on 08 April 2005
Oluwakemi Dare-Idowu, Igo Paulino, Cosme A. O. B. Figueiredo, Amauri F. Medeiros, Ricardo A. Buriti, Ana Roberta Paulino, and Cristiano M. Wrasse
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-81,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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Terrestrial ion circulation in space

Fri, 07/12/2019 - 16:32
Terrestrial ion circulation in space
Masatoshi Yamauchi
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-98,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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MMS observations of energetic oxygen ions at the low-latitude duskside magnetopause during intense substorms

Fri, 07/12/2019 - 16:32
MMS observations of energetic oxygen ions at the low-latitude duskside magnetopause during intense substorms
Chen Zeng, Suping Duan, Chi Wang, Lei Dai, Stephen Fuselier, James Burch, Roy Torbert, Barbara Giles, and Christopher Russell
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-90,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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GUMICS-4 analysis of interplanetary coronal mass ejection impact on Earth during low and typical Mach number solar winds

Thu, 07/11/2019 - 16:32
GUMICS-4 analysis of interplanetary coronal mass ejection impact on Earth during low and typical Mach number solar winds
Antti Lakka, Tuija I. Pulkkinen, Andrew P. Dimmock, Emilia Kilpua, Matti Ala-Lahti, Ilja Honkonen, Minna Palmroth, and Osku Raukunen
Ann. Geophys., 37, 561-579, https://doi.org/10.5194/angeo-37-561-2019, 2019
We study how the Earth's space environment responds to two different amplitude interplanetary coronal mass ejection (ICME) events that occurred in 2012 and 2014 by using the GUMICS-4 global MHD model. We examine local and large-scale dynamics of the Earth's space environment and compare simulation results to in situ data. It is shown that during moderate driving simulation agrees well with the measurements; however, GMHD results should be interpreted cautiously during strong driving.
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Influence of the Earth's ring current strength on Størmer's allowed and forbidden regions of charged particle motion

Tue, 07/09/2019 - 16:32
Influence of the Earth's ring current strength on Størmer's allowed and forbidden regions of charged particle motion
Alexander S. Lavrukhin, Igor I. Alexeev, and Ilya V. Tyutin
Ann. Geophys., 37, 535-547, https://doi.org/10.5194/angeo-37-535-2019, 2019
This paper concerns the question of whether the maximum Earth ring current strength exists and at which moment the ring current can start to break up, thus making a new mechanism of the ring current decrease during the magnetic storm. We study this effect using the Stormer theory of particle motion. After transition of critical strength, Stormer's inner trapping region opens up and the ring current charged particles get the opportunity to leave it, thus decreasing the current strength.
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Acceleration of protons and heavy ions to suprathermal energies during dipolarizations in the near-Earth magnetotail

Tue, 07/09/2019 - 16:32
Acceleration of protons and heavy ions to suprathermal energies during dipolarizations in the near-Earth magnetotail
Andrei Y. Malykhin, Elena E. Grigorenko, Elena A. Kronberg, Patrick W. Daly, and Ludmila V. Kozak
Ann. Geophys., 37, 549-559, https://doi.org/10.5194/angeo-37-549-2019, 2019
In this work we present an analysis of the dynamics of suprathermal ions of different masses (H+, He+, O+) during prolonged dipolarizations in the near-Earth magnetotail according to Cluster/RAPID observations in 2001–2005. All dipolarizations from our database were associated with fast flow braking and consisted of multiple dipolarization fronts (DFs). We found statistically that fluxes of suprathermal ions started to increase ~ 1  min before the dipolarization onset and continued.
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Mirror mode physics: Amplitude limit

Mon, 07/08/2019 - 16:32
Mirror mode physics: Amplitude limit
Rudolf A. Treumann and Wolfgang Baumjohann
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-86,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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Spatial and seasonal effects on the delayed ionospheric response to solar EUV changes

Mon, 07/08/2019 - 16:32
Spatial and seasonal effects on the delayed ionospheric response to solar EUV changes
Erik Schmölter, Jens Berdermann, Norbert Jakowski, and Christoph Jacobi
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-91,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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Assessing the role of planetary and gravity waves in the vertical structure of ozone over midlatitudinal Europe

Thu, 07/04/2019 - 16:32
Assessing the role of planetary and gravity waves in the vertical structure of ozone over midlatitudinal Europe
Peter Križan
Ann. Geophys., 37, 525-533, https://doi.org/10.5194/angeo-37-525-2019, 2019
We observe the planetary and gravity wave activity in the vertical profile of ozone at the mid-European ozonosonde stations The performance of the used detection method is satisfactory. There are differences in the following characteristics of the structure caused by the planetary and gravity wave: the annual variation, the size, and the vertical distribution. The results are influenced by the ozonosonde vertical resolution only for small and medium structures.
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Effect of latitudinally displaced gravity wave forcing in the lower stratosphere on the polar vortex stability

Wed, 07/03/2019 - 16:32
Effect of latitudinally displaced gravity wave forcing in the lower stratosphere on the polar vortex stability
Nadja Samtleben, Christoph Jacobi, Petr Pišoft, Petr Šácha, and Aleš Kuchař
Ann. Geophys., 37, 507-523, https://doi.org/10.5194/angeo-37-507-2019, 2019
Simulations of locally breaking gravity wave hot spots in the stratosphere show a suppression of wave propagation at midlatitudes, which is partly compensated for by additional wave propagation through the polar region. This leads to a displacement of the polar vortex towards lower latitudes. The effect is highly dependent on the position of the artificial gravity wave forcing. It is strongest (weakest) for hot spots at lower to middle latitudes (higher latitudes).
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Observing geometry effects on a GNSS based water vapor tomography solved by Least Squares and by Compressive Sensing

Wed, 07/03/2019 - 16:32
Observing geometry effects on a GNSS based water vapor tomography solved by Least Squares and by Compressive Sensing
Marion Heublein, Patrick Erik Bradley, and Stefan Hinz
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-87,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)

In this work, the effect of the observing geometry on the tomographic reconstruction quality of both a regularized Least Squares (LSQ) and a Compressive Sensing (CS) approach for neutrospheric water vapor tomography is compared based on synthetic Global Navigation Satellite System (GNSS) Slant Wet Delay (SWD) estimates. In this context, the term observing geometry mainly refers to the number of GNSS sites situated within a specific study area subdivided into a certain number of volumetric pixels (voxels) and to the number of signal directions available at each GNSS site. The novelties of this research are 1) the comparison of the observing geometry’s effects on the tomographic reconstruction accuracy when using LSQ resp. CS for the solution of the tomographic system and 2) the investigation of the effect of the signal directions’ variability on the tomographic reconstruction. The tomographic reconstruction is performed based on synthetic SWD data sets generated, for many samples of various observing geometry settings, based on wet refractivity information from the Weather Research and Forecasting (WRF) model. The validation of the achieved results focuses on a comparison of the refractivity estimates with the input WRF refractivities. The results show that the recommendation of Champollion et al. (2004) to discretize the analyzed study area into voxels with horizontal sizes comparable to the mean GNSS inter site distance represents a good rule of thumb for both LSQ and CS based tomography solutions. In addition, this research shows that CS needs a variety of at least 15 signal directions per site in order to estimate the refractivity field more accurately and more precisely than LSQ. Therefore, the use of CS is particularly recommended for water vapor tomography applications for which a high number of multi-GNSS SWD estimates are available.

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Mercury's subsolar sodium exosphere: an ab initio calculation to interpret MASCS/UVVS observations from MESSENGER

Tue, 07/02/2019 - 16:32
Mercury's subsolar sodium exosphere: an ab initio calculation to interpret MASCS/UVVS observations from MESSENGER
Diana Gamborino, Audrey Vorburger, and Peter Wurz
Ann. Geophys., 37, 455-470, https://doi.org/10.5194/angeo-37-455-2019, 2019
We propose that the temperature of the Na exosphere of Mercury near the subsolar point is not at high as proposed in previous works. Using a numerical model and the appropriate energy distributions for each release mechanism, we can explain observations made by MESSENGER in April 2012. Our results show that close to the surface, the dominant release mechanism for Na is evaporation due to the solar irradiation, and at high altitudes the best candidate is the release by micro-meteoroid impacts.
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Global analysis for periodic variations in gravity wave squared amplitudes and momentum fluxes in the middle atmosphere

Tue, 07/02/2019 - 16:32
Global analysis for periodic variations in gravity wave squared amplitudes and momentum fluxes in the middle atmosphere
Dan Chen, Cornelia Strube, Manfred Ern, Peter Preusse, and Martin Riese
Ann. Geophys., 37, 487-506, https://doi.org/10.5194/angeo-37-487-2019, 2019
In this paper, for the first time, absolute gravity wave momentum flux (GWMF) on temporal scales from terannual variation up to solar cycle length is investigated. The systematic spectral analysis of SABER absolute GWMF is presented and physically interpreted. The various roles of filtering and oblique propagating are discussed, which is likely an important factor for MLT dynamics, and hence can be used as a stringent test bed of the reproduction of such features in global models.
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Ozone and temperature decadal solar-cycle responses, and their relation to diurnal variations in the stratosphere, mesosphere, and lower thermosphere, based on measurements from SABER on TIMED

Tue, 07/02/2019 - 16:32
Ozone and temperature decadal solar-cycle responses, and their relation to diurnal variations in the stratosphere, mesosphere, and lower thermosphere, based on measurements from SABER on TIMED
Frank T. Huang and Hans G. Mayr
Ann. Geophys., 37, 471-485, https://doi.org/10.5194/angeo-37-471-2019, 2019
The sun’s radiation exhibits a cycle with a period of ~11 years. We need to understand how the atmospheric temperature and ozone react to this solar variation, as it can affect climate. The response depends on energy transfer, chemical reactions, and atmospheric motions. There is no consensus as to some details. For example, the responses depend on the local times of the variations. This study provides results of effects of local time on the responses, from 20 to 100 km, based on measurements.
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Air Density Induced Error on Wind Energy Estimation

Tue, 07/02/2019 - 16:32
Air Density Induced Error on Wind Energy Estimation
Aurore Dupré, Philippe Drobinski, Jordi Badosa, Christian Briard, and Riwal Plougonven
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-88,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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Density correction of NRLMSISE-00 in the middle atmosphere (20–100 km) based on TIMED/SABER density data

Mon, 07/01/2019 - 16:32
Density correction of NRLMSISE-00 in the middle atmosphere (20–100 km) based on TIMED/SABER density data
Xuan Cheng, Junfeng Yang, Cunying Xiao, and Xiong Hu
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-93,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
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.
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