Articles | Volume 38, issue 3
https://doi.org/10.5194/angeo-38-611-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/angeo-38-611-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
13 May 2020
Regular paper |
| 13 May 2020
| 13 May 2020
Occurrence climatology of equatorial plasma bubbles derived using FormoSat-3 ∕ COSMIC GPS radio occultation data
Ankur Kepkar
CORRESPONDING AUTHOR
Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin, 10623 Berlin, Germany
Section 1.1: Space Geodetic Techniques, German Research Centre for Geosciences GFZ, 14473 Potsdam, Germany
Christina Arras
Section 1.1: Space Geodetic Techniques, German Research Centre for Geosciences GFZ, 14473 Potsdam, Germany
Jens Wickert
Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin, 10623 Berlin, Germany
Section 1.1: Space Geodetic Techniques, German Research Centre for Geosciences GFZ, 14473 Potsdam, Germany
Harald Schuh
Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin, 10623 Berlin, Germany
Section 1.1: Space Geodetic Techniques, German Research Centre for Geosciences GFZ, 14473 Potsdam, Germany
Mahdi Alizadeh
Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin, 10623 Berlin, Germany
Faculty of Geodesy and Geomatics Engineering, K.N. Toosi University of Technology, 15433-19967 Tehran, Iran
Lung-Chih Tsai
Center for Space and Remote Sensing Research, National Central University, 32001 Chung-Li, Taiwan
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Miriam Sinnhuber, Christina Arras, Stefan Bender, Bernd Funke, Hanli Liu, Daniel R. Marsh, Thomas Reddmann, Eugene Rozanov, Timofei Sukhodolov, Monika E. Szelag, and Jan Maik Wissing
EGUsphere, https://doi.org/10.5194/egusphere-2024-2256, https://doi.org/10.5194/egusphere-2024-2256, 2024
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Formation of nitric oxide NO in the upper atmosphere varies with solar activity. Observations show that it starts a chain of processes in the entire atmosphere affecting the ozone layer and climate system. This is often underestimated in models. We compare five models which show large differences in simulated NO. Analysis of results point out problems related to the oxygen balance, and to the impact of atmospheric waves on dynamics. Both must be modeled well to reproduce the downward coupling.
Rohith Thundathil, Florian Zus, Galina Dick, and Jens Wickert
Geosci. Model Dev., 17, 3599–3616, https://doi.org/10.5194/gmd-17-3599-2024, https://doi.org/10.5194/gmd-17-3599-2024, 2024
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Global Navigation Satellite Systems (GNSS) provides moisture observations through its densely distributed ground station network. In this research, we assimilate a new type of observation called tropospheric gradient observations, which has never been incorporated into a weather model. We develop a forward operator for gradient-based observations and conduct an assimilation impact study. The study shows significant improvements in the model's humidity fields.
Ladina Steiner, Holger Schmithüsen, Jens Wickert, and Olaf Eisen
The Cryosphere, 17, 4903–4916, https://doi.org/10.5194/tc-17-4903-2023, https://doi.org/10.5194/tc-17-4903-2023, 2023
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The present study illustrates the potential of a combined Global Navigation Satellite System reflectometry and refractometry (GNSS-RR) method for accurate, simultaneous, and continuous estimation of in situ snow accumulation, snow water equivalent, and snow density time series. The combined GNSS-RR method was successfully applied on a fast-moving, polar ice shelf. The combined GNSS-RR approach could be highly advantageous for a continuous quantification of ice sheet surface mass balances.
Christoph Jacobi, Kanykei Kandieva, and Christina Arras
Adv. Radio Sci., 20, 85–92, https://doi.org/10.5194/ars-20-85-2023, https://doi.org/10.5194/ars-20-85-2023, 2023
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Sporadic E (Es) layers are thin regions of accumulated ions in the lower ionosphere. They can be observed by disturbances of GNSS links between low-Earth orbiting satellites and GNSS satellites. Es layers are influenced by neutral atmospheric tides and show the coupling between the neutral atmosphere and the ionosphere. Here we analyse migrating (sun-synchronous) and non-migrating tidal components in Es. The main signatures are migrating Es, but nonmigrating components are found as well.
S. Naderi Salim, M. M. Alizadeh, S. Chamankar, and H. Schuh
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., X-4-W1-2022, 575–580, https://doi.org/10.5194/isprs-annals-X-4-W1-2022-575-2023, https://doi.org/10.5194/isprs-annals-X-4-W1-2022-575-2023, 2023
S. Nasr-Azadani, M.M. Alizadeh, and H. Schuh
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., X-4-W1-2022, 595–602, https://doi.org/10.5194/isprs-annals-X-4-W1-2022-595-2023, https://doi.org/10.5194/isprs-annals-X-4-W1-2022-595-2023, 2023
Chaiyaporn Kitpracha, Robert Heinkelmann, Markus Ramatschi, Kyriakos Balidakis, Benjamin Männel, and Harald Schuh
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2022-238, https://doi.org/10.5194/amt-2022-238, 2022
Preprint withdrawn
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In this study, we expected to learn what are the potential effects of GNSS atmospheric delays from this unique experiment. The results show that the instrument effects on GNSS zenith delays were mitigated by using the same instrument. The radome causes unexpected bias of GNSS zenith delays in this study. In order to calibrate the instrumental effects, we set up the GNSS co-location site experiment to demonstrate calibrating GNSS instrumental effects.
Karina Wilgan, Galina Dick, Florian Zus, and Jens Wickert
Atmos. Meas. Tech., 15, 21–39, https://doi.org/10.5194/amt-15-21-2022, https://doi.org/10.5194/amt-15-21-2022, 2022
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The assimilation of GNSS data in weather models has a positive impact on the forecasts. The impact is still limited due to using only the GPS zenith direction parameters. We calculate and validate more advanced tropospheric products from three satellite systems: the US American GPS, Russian GLONASS and European Galileo. The quality of all the solutions is comparable; however, combining more GNSS systems enhances the observations' geometry and improves the quality of the weather forecasts.
Benjamin Männel, Florian Zus, Galina Dick, Susanne Glaser, Maximilian Semmling, Kyriakos Balidakis, Jens Wickert, Marion Maturilli, Sandro Dahlke, and Harald Schuh
Atmos. Meas. Tech., 14, 5127–5138, https://doi.org/10.5194/amt-14-5127-2021, https://doi.org/10.5194/amt-14-5127-2021, 2021
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Within the MOSAiC expedition, GNSS was used to monitor variations in atmospheric water vapor. Based on 15 months of continuously tracked data, coordinates and hourly zenith total delays (ZTDs) were determined using kinematic precise point positioning. The derived ZTD values agree within few millimeters with ERA5 and terrestrial GNSS and VLBI stations. The derived integrated water vapor corresponds to the frequently launched radiosondes (0.08 ± 0.04 kg m−2, rms of the differences of 1.47 kg m−2).
Chaiyaporn Kitpracha, Robert Heinkelmann, Markus Ramatschi, Kyriakos Balidakis, Benjamin Männel, and Harald Schuh
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2021-87, https://doi.org/10.5194/amt-2021-87, 2021
Preprint withdrawn
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In this study, we expected to learn what are the potential effects of GNSS atmospheric delays from this unique experiment. The results show that the instrument effects on GNSS zenith delays were mitigated by using the same instrument. The radome causes unexpected bias of GNSS zenith delays in this study. Additionally, multipath effects at low-elevation observations degraded the tropospheric east gradients.
Xiao Chang, Benjamin Männel, and Harald Schuh
Adv. Geosci., 55, 33–45, https://doi.org/10.5194/adgeo-55-33-2021, https://doi.org/10.5194/adgeo-55-33-2021, 2021
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This study focuses on the comparison of different solar radiation pressure (SRP) strategies combined with a-priori information and empirical SRP parameterization. Analysis of precise orbits as well as estimated empirical SRP parameters based on various SRP strategies shows visible differences and indicates the deficiencies of a-priori model or empirical parameterization. The orbit difference patterns presented in this study may give the view on how to improve the current SRP models.
Zhilu Wu, Yanxiong Liu, Yang Liu, Jungang Wang, Xiufeng He, Wenxue Xu, Maorong Ge, and Harald Schuh
Atmos. Meas. Tech., 13, 4963–4972, https://doi.org/10.5194/amt-13-4963-2020, https://doi.org/10.5194/amt-13-4963-2020, 2020
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The HY-2A calibration microwave radiometer (CMR) water vapor product is validated using ground-based GNSS observations along the coastline and shipborne GNSS observations over the Indian Ocean. The validation result shows that HY-2A CMR PWV agrees well with ground-based GNSS PWV, with 2.67 mm in rms within 100 km and an RMS of 1.57 mm with shipborne GNSS for the distance threshold of 100 km. Ground-based GNSS and shipborne GNSS agree with HY-2A CMR well.
Andrea K. Steiner, Florian Ladstädter, Chi O. Ao, Hans Gleisner, Shu-Peng Ho, Doug Hunt, Torsten Schmidt, Ulrich Foelsche, Gottfried Kirchengast, Ying-Hwa Kuo, Kent B. Lauritsen, Anthony J. Mannucci, Johannes K. Nielsen, William Schreiner, Marc Schwärz, Sergey Sokolovskiy, Stig Syndergaard, and Jens Wickert
Atmos. Meas. Tech., 13, 2547–2575, https://doi.org/10.5194/amt-13-2547-2020, https://doi.org/10.5194/amt-13-2547-2020, 2020
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High-quality observations are critically important for monitoring the Earth’s changing climate. We provide information on the consistency and long-term stability of observations from GPS radio occultation (RO). We assess, for the first time, RO records from multiple RO missions and all major RO data providers. Our results quantify where RO can be used for reliable trend assessment and confirm its climate quality.
Gustavo Mansur, Pierre Sakic, Benjamin Männel, and Harald Schuh
Adv. Geosci., 50, 57–64, https://doi.org/10.5194/adgeo-50-57-2020, https://doi.org/10.5194/adgeo-50-57-2020, 2020
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Nowadays, new GNSS, like European Galileo or Chinese Beidou are available. Some members of the International GNSS Service (IGS) provide multi-GNSS precise satellite orbits, but no final orbit combination exists yet. We developed a new algorithm to combine satellite orbits for all GNSS constellations. Two different strategies were applied. To validate our results we compared our GPS orbits with the official IGS orbits. Our results show that the best strategy applied reached an agreement ~15 mm.
S. Khajeh, A. A. Ardalan, and H. Schuh
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4-W18, 597–603, https://doi.org/10.5194/isprs-archives-XLII-4-W18-597-2019, https://doi.org/10.5194/isprs-archives-XLII-4-W18-597-2019, 2019
Christoph Jacobi and Christina Arras
Adv. Radio Sci., 17, 213–224, https://doi.org/10.5194/ars-17-213-2019, https://doi.org/10.5194/ars-17-213-2019, 2019
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We analyze tidal phases and related wind shear in the mesosphere and
lower thermosphere as observed by a meteor radar. The wind shear phases are compared with those of sporadic E occurrence rates, which were derived from GPS radio occultation observations. We find good correspondence between radar derived wind shear and sporadic E phases for the semidiurnal, terdiurnal, and quarterdiurnal tidal components, but not for the diurnal tide.
E. Sinem Ince, Franz Barthelmes, Sven Reißland, Kirsten Elger, Christoph Förste, Frank Flechtner, and Harald Schuh
Earth Syst. Sci. Data, 11, 647–674, https://doi.org/10.5194/essd-11-647-2019, https://doi.org/10.5194/essd-11-647-2019, 2019
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ICGEM is a non-profit scientific service that contributes to any research area in which the use of gravity information is essential. ICGEM offers the largest collection of global gravity field models, interactive calculation and visualisation services and delivers high-quality datasets to researchers and students in geodesy, geophysics, glaciology, hydrology, oceanography, and climatology and most importantly general public. Static, temporal, and topographic gravity field models are available.
Christoph Jacobi, Christina Arras, Christoph Geißler, and Friederike Lilienthal
Ann. Geophys., 37, 273–288, https://doi.org/10.5194/angeo-37-273-2019, https://doi.org/10.5194/angeo-37-273-2019, 2019
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Sporadic E (Es) layers in the Earth's ionosphere are produced by ion convergence due to vertical wind shear in the presence of a horizontal component of the Earth's magnetic field. We present analyses of the 6 h tidal signatures in ES occurrence rates derived from GPS radio observations. Times of maxima in ES agree well with those of negative wind shear obtained from radar observation. The global distribution of ES amplitudes agrees with wind shear amplitudes from numerical modeling.
Laysa C. A. Resende, Christina Arras, Inez S. Batista, Clezio M. Denardini, Thainá O. Bertollotto, and Juliano Moro
Ann. Geophys., 36, 587–593, https://doi.org/10.5194/angeo-36-587-2018, https://doi.org/10.5194/angeo-36-587-2018, 2018
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We present new results on the behavior of sporadic E layers (Es layers) using GPS (global positioning system) radio occultation (RO) measurements obtained from the FORMOSAT-3/COSMIC satellites and digisonde data over Cachoeira Paulista, a low-latitude station in Brazil.
Fadwa Alshawaf, Kyriakos Balidakis, Galina Dick, Stefan Heise, and Jens Wickert
Atmos. Meas. Tech., 10, 3117–3132, https://doi.org/10.5194/amt-10-3117-2017, https://doi.org/10.5194/amt-10-3117-2017, 2017
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In this paper, we aimed at estimating climatic trends using precipitable water vapor time series and surface measurements of air temperature in Germany. We used GNSS, ERA-Interim, and synoptic data. The results show mainly a positive trend in precipitable water vapor and temperature with an increase in the trend when moving to northeastern Germany.
Cuixian Lu, Florian Zus, Maorong Ge, Robert Heinkelmann, Galina Dick, Jens Wickert, and Harald Schuh
Atmos. Meas. Tech., 9, 5965–5973, https://doi.org/10.5194/amt-9-5965-2016, https://doi.org/10.5194/amt-9-5965-2016, 2016
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The recent dramatic development of multi-GNSS constellations brings great opportunities and potential for more enhanced precise positioning, navigation, timing, and other applications. In this contribution, we develop a numerical weather model (NWM) constrained PPP processing system to improve the multi-GNSS precise positioning. Compared to the standard PPP solution, significant improvements of both convergence time and positioning accuracy are achieved with the NWM-constrained PPP solution.
Fadwa Alshawaf, Galina Dick, Stefan Heise, Tzvetan Simeonov, Sibylle Vey, Torsten Schmidt, and Jens Wickert
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2016-151, https://doi.org/10.5194/amt-2016-151, 2016
Revised manuscript not accepted
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In this work, we use time series from GNSS, European Center for Medium-Range Weather Forecasts Reanalysis (ERA-Interim) data, and meteorological measurements to evaluate climate evolution in Central Europe. We monitor different atmospheric variables such as temperature, PWV, precipitation, and snow cover. The results show an increasing trend the water vapor time series that are correlated with the trend the temperature tme series. The average increase of water vapor is about 0.3–0.6 mm/decade .
T. Ning, J. Wang, G. Elgered, G. Dick, J. Wickert, M. Bradke, M. Sommer, R. Querel, and D. Smale
Atmos. Meas. Tech., 9, 79–92, https://doi.org/10.5194/amt-9-79-2016, https://doi.org/10.5194/amt-9-79-2016, 2016
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Integrated water vapour (IWV) obtained from GNSS is to be developed into a GRUAN data product. In addition to the actual measurement, this data product needs to provide an estimate of the measurement uncertainty at the same time resolution as the actual measurement. The method developed in the paper fulfils the requirement by assigning a specific uncertainty to each data point. The method is also valuable for all applications of GNSS IWV data in atmospheric research and weather forecast.
M. Shangguan, S. Heise, M. Bender, G. Dick, M. Ramatschi, and J. Wickert
Ann. Geophys., 33, 55–61, https://doi.org/10.5194/angeo-33-55-2015, https://doi.org/10.5194/angeo-33-55-2015, 2015
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We present validation results covering 184 days of SIWV (slant-integrated water vapor) observed by a ground-based GPS receiver and a WVR (water vapor radiometer). SIWV data from GPS and WVR generally show good agreement, and the relation between their differences and possible influential factors are analyzed. The differences in SIWV show a relative elevation dependence. Besides the elevation, dependencies between the atmospheric humidity conditions, temperature and differences in SIWV are found.
F. Zus, G. Beyerle, S. Heise, T. Schmidt, and J. Wickert
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amtd-7-12719-2014, https://doi.org/10.5194/amtd-7-12719-2014, 2014
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Related subject area
Subject: Earth's ionosphere & aeronomy | Keywords: Ionospheric irregularities
Simultaneous OI 630 nm imaging observations of thermospheric gravity waves and associated revival of fossil depletions around midnight near the equatorial ionization anomaly (EIA) crest
F-region drift current and magnetic perturbation distribution by the X-wave heating ionosphere
Fluid models capturing Farley–Buneman instabilities
Temporal and altitudinal variability of the spread F observed by the VHF radar over Christmas Island
Effect of neutral winds on the creation of non-specular meteor trail echoes
Simultaneous ground-based and in situ Swarm observations of equatorial F-region irregularities over Jicamarca
Localized total electron content enhancements in the Southern Hemisphere
Stratification observed by the in situ plasma density measurements from the Swarm satellites
Structural characterization of the equatorial F region plasma irregularities in the multifractal context
Traits of sub-kilometre F-region irregularities as seen with the Swarm satellites
Equatorial plasma bubbles developing around sunrise observed by an all-sky imager and global navigation satellite system network during storm time
Investigation of the relationship between the spatial gradient of total electron content (TEC) between two nearby stations and the occurrence of ionospheric irregularities
Research on small-scale structures of ice particle density and electron density in the mesopause region
On developing a new ionospheric plasma index for Brazilian equatorial F region irregularities
Observation of seasonal asymmetry in the range spread F occurrence at different longitudes during low and moderate solar activity
Identifying a possible stratification phenomenon in ionospheric F2 layer using the data observed by the DEMETER satellite: method and results
Global sounding of F region irregularities by COSMIC during a geomagnetic storm
On the convection of ionospheric density features
The ionospheric response over the UK to major bombing raids during World War II
Navin Parihar, Saranya Padincharapad, Anand Kumar Singh, Prasanna Mahavarkar, and Ashok Priyadarshan Dimri
Ann. Geophys., 42, 131–143, https://doi.org/10.5194/angeo-42-131-2024, https://doi.org/10.5194/angeo-42-131-2024, 2024
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Gravity waves are well known for deforming the bottom-side plasma of the F region into the wavelike ionization structures which then act as a seed for Rayleigh–Taylor instability, which in turn generates irregularities. The present study features midnight fossil airglow depletions that revived due to ongoing gravity wave (GW) activity and turned into an active depletion.
Yong Li, Hui Li, Jian Wu, Xingbao Lv, Chengxun Yuan, Ce Li, and Zhongxiang Zhou
Ann. Geophys., 41, 541–549, https://doi.org/10.5194/angeo-41-541-2023, https://doi.org/10.5194/angeo-41-541-2023, 2023
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According to plasma drift theory, charged particles will drift when they are subjected to external forces, thus generating a drift current. In this paper, we establish the drift current and magnetic perturbation model in the ionosphere. Based on the HAARP ionospheric background, we analyze the properties of drift current and magnetic perturbation. This work provides guidance for a better understanding of ionospheric current distributions and magnetic perturbations.
Enrique L. Rojas, Keaton J. Burns, and David L. Hysell
Ann. Geophys., 41, 281–287, https://doi.org/10.5194/angeo-41-281-2023, https://doi.org/10.5194/angeo-41-281-2023, 2023
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The standard linear fluid theory of Farley and Buneman predicts that kinetic physics are required to avoid the artificial growth of smaller structures. We explore the possibility of simulating the Farley–Buneman instability using, for the first time, a fully fluid five-moment model. This is the first time a fully fluid model has been used to simulate the Farley–Buneman instability. The results obtained with both models are qualitatively consistent with the ones from kinetic simulations.
Ricardo Yvan de La Cruz Cueva, Eurico Rodrigues de Paula, and Acácio Cunha Neto
Ann. Geophys., 40, 563–570, https://doi.org/10.5194/angeo-40-563-2022, https://doi.org/10.5194/angeo-40-563-2022, 2022
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This paper brings analysis of spread-F echoes along the years of 2003 to 2012 from Christmas Island radar. We organize our data with the objective of observing the peak time and altitude distribution. Our results indicate the peak time occurrence of echoes to be distributed closer to local sunset during solar maximum and around midnight during solar minimum; meanwhile, the peak altitude echoes show higher altitude occurrences during solar maxima and lower altitudes during solar minima.
Freddy Galindo, Julio Urbina, and Lars Dyrud
Ann. Geophys., 39, 709–719, https://doi.org/10.5194/angeo-39-709-2021, https://doi.org/10.5194/angeo-39-709-2021, 2021
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Micro-size particles entering the Earth’s atmosphere do not emit enough light to be observed as meteors, but they can be probed with radars. The echo from these meteors depends on particle size and the atmosphere in which the particle travels. In this paper, we study the importance of neutral winds in forming meteor returns sensed by radars. We show that meteor trails can exhibit unique radar signatures due to neutral winds, explaining unique signatures in radar maps.
Sharon Aol, Stephan Buchert, Edward Jurua, and Marco Milla
Ann. Geophys., 38, 1063–1080, https://doi.org/10.5194/angeo-38-1063-2020, https://doi.org/10.5194/angeo-38-1063-2020, 2020
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Ionospheric irregularities are a common phenomenon in the low-latitude ionosphere. In this paper, we compared simultaneous observations of plasma plumes by the JULIA radar, ionogram spread F generated from ionosonde observations installed at the Jicamarca Radio Observatory, and irregularities observed in situ by Swarm to determine whether Swarm in situ observations can be used as indicators of the presence of plasma plumes and spread F on the ground.
Ilya K. Edemskiy
Ann. Geophys., 38, 591–601, https://doi.org/10.5194/angeo-38-591-2020, https://doi.org/10.5194/angeo-38-591-2020, 2020
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This paper investigates a feature in the Southern Hemisphere ionosphere that is observed near midday in the form of a localized enhancement of the electron density. After being discovered in global ionospheric maps, the enhancements were also observed via in situ measurements of the electron concentration. The probability of detecting an enhancement is maximal during the autumn–winter period and does not seem to be directly dependent on geomagnetic indices or solar wind parameters.
Xiuying Wang, Wanli Cheng, Zihan Zhou, Dehe Yang, Jing Cui, and Feng Guo
Ann. Geophys., 38, 517–526, https://doi.org/10.5194/angeo-38-517-2020, https://doi.org/10.5194/angeo-38-517-2020, 2020
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To get the global distribution of the stratification phenomenon, the in situ plasma density measurements, obtained by the Swarm satellites orbiting at different altitudes above the F2 peak, are used to study this phenomenon. The continuous morphology of this phenomenon and its features along the latitudinal direction are obtained, and a new discovery from the in situ measurements is the stratification on southern mid-latitudes.
Neelakshi Joshi, Reinaldo R. Rosa, Siomel Savio, Esfhan Alam Kherani, Francisco Carlos de Meneses, Stephan Stephany, and Polinaya Muralikrishna
Ann. Geophys., 38, 445–456, https://doi.org/10.5194/angeo-38-445-2020, https://doi.org/10.5194/angeo-38-445-2020, 2020
Sharon Aol, Stephan Buchert, and Edward Jurua
Ann. Geophys., 38, 243–261, https://doi.org/10.5194/angeo-38-243-2020, https://doi.org/10.5194/angeo-38-243-2020, 2020
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During the night, in the F region, equatorial ionospheric irregularities manifest as plasma depletions observed by satellites and may cause radio signals to fluctuate. We checked the distribution traits of ionospheric F-region irregularities in the low latitudes using 16 Hz electron density observations made by the faceplate onboard Swarm satellites. Using the high-resolution faceplate data, we were able to identify ionospheric irregularities of scales of only a few hundred metres.
Kun Wu, Jiyao Xu, Xinan Yue, Chao Xiong, Wenbin Wang, Wei Yuan, Chi Wang, Yajun Zhu, and Ji Luo
Ann. Geophys., 38, 163–177, https://doi.org/10.5194/angeo-38-163-2020, https://doi.org/10.5194/angeo-38-163-2020, 2020
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An equatorial plasma bubble (EPB) event, emerging near dawn and developing after sunrise, was simultaneously observed by an all-sky imager and the global navigation satellite system (GNSS) network. The observed EPBs showed westward drifts, different from post-sunset EPBs. The EPBs occurred in the recovery phase of a geomagnetic storm, possibly playing a key role in initializing their developments. The results provide a new perspective of EPBs, enriching our knowledge of ionospheric irregularity.
Teshome Dugassa, John Bosco Habarulema, and Melessew Nigussie
Ann. Geophys., 37, 1161–1180, https://doi.org/10.5194/angeo-37-1161-2019, https://doi.org/10.5194/angeo-37-1161-2019, 2019
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The relation between the occurrence of ionospheric irregularities and the spatial gradient of TEC derived from two closely located stations, located within the equatorial region over Ethiopia, was investigated. The relationship between σ(∆TEC/∆long) and ROTIave correlate linearly with correlation coefficients of C = 0.7975 and C = 0.7915 over ASAB and DEBK, respectively. In addition to latitudinal gradients, the longitudinal gradient of TEC has a significant contribution to the TEC fluctuations.
Ruihuan Tian, Jian Wu, Jinxiu Ma, Yonggan Liang, Hui Li, Chengxun Yuan, Yongyuan Jiang, and Zhongxiang Zhou
Ann. Geophys., 37, 1079–1094, https://doi.org/10.5194/angeo-37-1079-2019, https://doi.org/10.5194/angeo-37-1079-2019, 2019
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The density distribution of ice particles and electrons near the boundary of the polar mesosphere summer echo (PMSE) region is studied. The results show that when the radius distribution function of the condensation nucleus is a Gaussian type, for a certain range of the condensation core radius, sharp peaks with a meter scale appear in the density profiles of ice particles and electrons. These small-scale structures of electron density may be one of the causes of the PMSE phenomenon.
Laysa Cristina Araujo Resende, Clezio Marcos Denardini, Giorgio Arlan Silva Picanço, Juliano Moro, Diego Barros, Cosme Alexandre Oliveira Barros Figueiredo, and Régia Pereira Silva
Ann. Geophys., 37, 807–818, https://doi.org/10.5194/angeo-37-807-2019, https://doi.org/10.5194/angeo-37-807-2019, 2019
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The Brazilian Space Weather Study and Monitoring Program (Embrace) has been developing different indexes that describe ionospheric effects in the Brazilian sector. The main purpose of this work was to produce a new ionospheric scale based on the analysis of the ionospheric plasma drift velocity. We analyzed 7 years of data in order to construct a standardized scale. The results of this new index allow us to evaluate the impacts of ionospheric phenomena in the space weather environment.
Abimbola O. Afolayan, Mandeep Jit Singh, Mardina Abdullah, Suhaila M. Buhari, Tatsuhiro Yokoyama, and Pornchai Supnithi
Ann. Geophys., 37, 733–745, https://doi.org/10.5194/angeo-37-733-2019, https://doi.org/10.5194/angeo-37-733-2019, 2019
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The equatorial spread F (ESF) is a nighttime phenomenon that can have a deleterious effect on the radio communication system. We investigated the parameters influencing the seasonal morphology of the range type spread F (RSF) using ionosonde data from different longitude sectors. The observed RSF occurrence features showed distinct patterns across these sectors, including seasonal asymmetry. This asymmetry was attributed to the probable effect of the zonal wind reversal and gravity waves.
Xiuying Wang, Dehe Yang, Dapeng Liu, and Wei Chu
Ann. Geophys., 37, 645–655, https://doi.org/10.5194/angeo-37-645-2019, https://doi.org/10.5194/angeo-37-645-2019, 2019
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To check the difference between data observed at different altitudes of the DEMETER satellite, a statistical method is adopted to evaluate whether data difference is caused by normal data fluctuation or by altitude adjustment. Based on the method, in situ electron density data at higher altitudes are found to be greater than those at lower altitudes. We speculate that this phenomenon is caused by stratification above F2 peak region. The proposed method is useful when comparing fluctuated data.
Klemens Hocke, Huixin Liu, Nicholas Pedatella, and Guanyi Ma
Ann. Geophys., 37, 235–242, https://doi.org/10.5194/angeo-37-235-2019, https://doi.org/10.5194/angeo-37-235-2019, 2019
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The GPS radio occultation data of the COSMIC-FORMOSAT-3 mission are used to visualize the global distribution of ionospheric irregularities in the F2 region during a geomagnetic storm, at solar minimum, and at solar maximum.
John D. de Boer, Jean-Marc A. Noël, and Jean-Pierre St.-Maurice
Ann. Geophys., 37, 201–214, https://doi.org/10.5194/angeo-37-201-2019, https://doi.org/10.5194/angeo-37-201-2019, 2019
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Modelling aurorae, we asked what boundary condition (BC) to use for the E field on the upper boundary. Typically a Dirichlet BC is used, since processes above the domain generate E. But then conductivity structures trigger FACs driven immediately by magnetospheric convection, even though it is a finite energy source, delayed by the Alfvén speed. If the BC is not ideal, then E x B drift in the ionosphere depends on the plasma's properties. So we investigated.
Christopher J. Scott and Patrick Major
Ann. Geophys., 36, 1243–1254, https://doi.org/10.5194/angeo-36-1243-2018, https://doi.org/10.5194/angeo-36-1243-2018, 2018
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The variability of the Earth's ionosphere (the electrified region of the Earth's upper atmosphere) results from external forcing from above (through solar activity and space weather effects) and from below (via natural sources such as lightning storms and tectonics). Bombing raids over Europe during World War II were used to determine the quantitative impact of explosions on the ionosphere. It was found that raids using more than 300 tonnes of explosives weakened the ionosphere for up to 5 h.
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Short summary
The paper focuses on the analyses of the global occurrence of equatorial plasma bubble events using S4 data that were calculated from GPS radio occultation measurements of the FormoSat-3/COSMIC mission. The advantage in using radio occultation data is that we get information not only on the occurrence and intensity of the equatorial bubble events, but also on the altitude distribution. We analyzed a 10.5-year time series of COSMIC data and demonstrated a strong dependence on the solar cycle.
The paper focuses on the analyses of the global occurrence of equatorial plasma bubble events...
Special issue