Articles | Volume 37, issue 2
https://doi.org/10.5194/angeo-37-235-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-37-235-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Global sounding of F region irregularities by COSMIC during a geomagnetic storm
Institute of Applied Physics, University of Bern, Bern, Switzerland
Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
Huixin Liu
Department of Earth and Planetary Science, Kyushu University, Fukuoka, Japan
Nicholas Pedatella
High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado,
USA
Guanyi Ma
National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China
Related authors
Leonie Bernet, Elmar Brockmann, Thomas von Clarmann, Niklaus Kämpfer, Emmanuel Mahieu, Christian Mätzler, Gunter Stober, and Klemens Hocke
Atmos. Chem. Phys., 20, 11223–11244, https://doi.org/10.5194/acp-20-11223-2020, https://doi.org/10.5194/acp-20-11223-2020, 2020
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With global warming, water vapour increases in the atmosphere. Water vapour is an important gas because it is a natural greenhouse gas and affects the formation of clouds, rain and snow. How much water vapour increases can vary in different regions of the world. To verify if it increases as expected on a regional scale, we analysed water vapour measurements in Switzerland. We found that water vapour generally increases as expected from temperature changes, except in winter.
Franziska Schranz, Jonas Hagen, Gunter Stober, Klemens Hocke, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 10791–10806, https://doi.org/10.5194/acp-20-10791-2020, https://doi.org/10.5194/acp-20-10791-2020, 2020
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We measured middle-atmospheric ozone, water vapour and zonal and meridional wind with two ground-based microwave radiometers which are located at Ny-Alesund, Svalbard, in the Arctic. In this article we present measurements of the small-scale horizontal ozone gradients during winter 2018/2019. We found a distinct seasonal variation of the ozone gradients which is linked to the planetary wave activity. We further present the signatures of the SSW in the ozone, water vapour and wind measurements.
Eliane Maillard Barras, Alexander Haefele, Liliane Nguyen, Fiona Tummon, William T. Ball, Eugene V. Rozanov, Rolf Rüfenacht, Klemens Hocke, Leonie Bernet, Niklaus Kämpfer, Gerald Nedoluha, and Ian Boyd
Atmos. Chem. Phys., 20, 8453–8471, https://doi.org/10.5194/acp-20-8453-2020, https://doi.org/10.5194/acp-20-8453-2020, 2020
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To determine the part of the variability of the long-term ozone profile trends coming from measurement timing, we estimate microwave radiometer trends for each hour of the day with a multiple linear regression model. The variation in the trend with local solar time is not significant at the 95 % confidence level either in the stratosphere or in the low mesosphere. We conclude that systematic sampling differences between instruments cannot explain significant differences in trend estimates.
Jonas Hagen, Klemens Hocke, Gunter Stober, Simon Pfreundschuh, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 2367–2386, https://doi.org/10.5194/acp-20-2367-2020, https://doi.org/10.5194/acp-20-2367-2020, 2020
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The middle atmosphere (30 to 70 km altitude) is stratified and, despite very strong horizontal winds, there is less mixing between the horizontal layers. An important driver for the energy exchange between the layers in this regime is atmospheric tides, which are waves that are driven by the diurnal cycle of solar heating. We measure these tides in the wind field for the first time using a ground-based passive instrument. Ultimately, such measurements could be used to improve atmospheric models.
Klemens Hocke, Leonie Bernet, Jonas Hagen, Axel Murk, Matthias Renker, and Christian Mätzler
Atmos. Chem. Phys., 19, 12083–12090, https://doi.org/10.5194/acp-19-12083-2019, https://doi.org/10.5194/acp-19-12083-2019, 2019
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The Tropospheric Water Radiometer (TROWARA) observed an enhanced intensity of short-term integrated water vapour (IWV) fluctuations during daytime in summer. These IWV fluctuations are possibly related to latent heat flux and thermal convective activity in the lower troposphere. The observed climatology and spectra of IWV fluctuations might be useful for modelling studies of water vapour convection in the atmospheric boundary layer at mid latitudes.
Franziska Schranz, Brigitte Tschanz, Rolf Rüfenacht, Klemens Hocke, Mathias Palm, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 9927–9947, https://doi.org/10.5194/acp-19-9927-2019, https://doi.org/10.5194/acp-19-9927-2019, 2019
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The dynamics of the Arctic middle atmosphere above Ny-Ålesund, Svalbard (79° N, 12° E) is investigated using 3 years of H2O and O3 measurements from ground-based microwave radiometers. We found the signals of atmospheric phenomena like sudden stratospheric warmings, polar vortex shifts, effective descent rates of water vapour and periodicities in our data. Additionally, a comprehensive intercomparison is performed with models and measurements from ground-based, in situ and satellite instruments.
Klemens Hocke, Jonas Hagen, Franziska Schranz, and Leonie Bernet
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2019-630, https://doi.org/10.5194/acp-2019-630, 2019
Preprint withdrawn
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The dense sampling of geopotential height (GPH) profiles of the microwave limb sounder (MLS) on NASA's satellite Aura is appropriate for detection of mesospheric gravity waves. Up to now, the global distribution of mesospheric gravity wave activity is relatively unknown. The study focuses on the relation of mesospheric gravity waves to major sudden stratospheric warmings.
Martin Lainer, Klemens Hocke, Ellen Eckert, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 6611–6620, https://doi.org/10.5194/acp-19-6611-2019, https://doi.org/10.5194/acp-19-6611-2019, 2019
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A middle atmospheric water vapor time series of more than 11 years (April 2007 to May 2018) from the NDACC microwave remote sensing site at Bern (Switzerland) is investigated to estimate the trend by means of a robust multilinear parametric trend model. Between 61 and 72 km altitude a significant decline in water vapor could be detected. The reduction of water vapor maximizes to about −12 % per decade at 72 km altitude.
Jinghua Li, Guanyi Ma, Klemens Hocke, Qingtao Wan, Jiangtao Fan, and Xiaolan Wang
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2019-64, https://doi.org/10.5194/angeo-2019-64, 2019
Revised manuscript not accepted
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Local occurrence rate (LOR) is defined to clarify the characteristics of ionospheric irregularities together with monthly occurrence rate (MOR) at 20–29° N in solar minimum, medium and maximum years of 2008, 2003 and 2014. MOR of irregularities in May/June is larger than that in equinoxes, which is different with the equatorial plasma bubbles. LOR shows that the irregularities at 26–29° N in May/June are more frequently happened and have smaller spatiotemporal scales than those at lower latitudes.
Leonie Bernet, Thomas von Clarmann, Sophie Godin-Beekmann, Gérard Ancellet, Eliane Maillard Barras, René Stübi, Wolfgang Steinbrecht, Niklaus Kämpfer, and Klemens Hocke
Atmos. Chem. Phys., 19, 4289–4309, https://doi.org/10.5194/acp-19-4289-2019, https://doi.org/10.5194/acp-19-4289-2019, 2019
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After severe ozone depletion, upper stratospheric ozone has started to recover in recent years. However, stratospheric ozone trends from various data sets still show differences. To partly explain such differences, we investigate how the trends are affected by different factors, for example, anomalies in the data. We show how trend estimates can be improved by considering such anomalies and present updated stratospheric ozone trends from ground data measured in central Europe.
Martin Lainer, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 18, 12061–12074, https://doi.org/10.5194/acp-18-12061-2018, https://doi.org/10.5194/acp-18-12061-2018, 2018
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A long continuous record (in total 7 years) of middle atmospheric water vapor at the midlatitude NDACC station in Bern is investigated to study quasi 2-day wave oscillations (Q2DWs). We present monthly climatologies of the wave amplitudes and show the periods that the Q2DWs developed. What we observe is very-high-frequency variability. An autobicoherence analysis revealed nonlinear phase couplings between Q2DWs and other atmospheric waves. Our results are useful for model validation purposes.
Martin Lainer, Klemens Hocke, Rolf Rüfenacht, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 14905–14917, https://doi.org/10.5194/acp-17-14905-2017, https://doi.org/10.5194/acp-17-14905-2017, 2017
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We report on middle-atmospheric water vapor measurements above Bern from the ground-based microwave radiometer MIAWARA (NDACC affiliated) during two winter periods of 6 months. Quasi 18 h oscillations of mesospheric water vapor above 0.1 hPa are observed. Further, the 18 h wave is seen in a zonal wind data set from the Doppler wind radiometer WIRA. Inertia-gravity-wave-induced fluctuations or a nonlinear coupling between tides and quasi 2-day waves are considered as possible drivers.
Klemens Hocke, Francisco Navas-Guzmán, Lorena Moreira, Leonie Bernet, and Christian Mätzler
Atmos. Chem. Phys., 17, 12121–12131, https://doi.org/10.5194/acp-17-12121-2017, https://doi.org/10.5194/acp-17-12121-2017, 2017
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We derive the annual and semi-annual oscillations in cloud fraction (CF), integrated liquid water (ILW) and integrated water vapour (IWV) from the long-term measurements of the TROWARA radiometer in Bern, Switzerland. Further, we find a weekly cycle of CF and ILW from June to September with increased values on Saturday, Sunday and Monday.
Wolfgang Steinbrecht, Lucien Froidevaux, Ryan Fuller, Ray Wang, John Anderson, Chris Roth, Adam Bourassa, Doug Degenstein, Robert Damadeo, Joe Zawodny, Stacey Frith, Richard McPeters, Pawan Bhartia, Jeannette Wild, Craig Long, Sean Davis, Karen Rosenlof, Viktoria Sofieva, Kaley Walker, Nabiz Rahpoe, Alexei Rozanov, Mark Weber, Alexandra Laeng, Thomas von Clarmann, Gabriele Stiller, Natalya Kramarova, Sophie Godin-Beekmann, Thierry Leblanc, Richard Querel, Daan Swart, Ian Boyd, Klemens Hocke, Niklaus Kämpfer, Eliane Maillard Barras, Lorena Moreira, Gerald Nedoluha, Corinne Vigouroux, Thomas Blumenstock, Matthias Schneider, Omaira García, Nicholas Jones, Emmanuel Mahieu, Dan Smale, Michael Kotkamp, John Robinson, Irina Petropavlovskikh, Neil Harris, Birgit Hassler, Daan Hubert, and Fiona Tummon
Atmos. Chem. Phys., 17, 10675–10690, https://doi.org/10.5194/acp-17-10675-2017, https://doi.org/10.5194/acp-17-10675-2017, 2017
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Thanks to the 1987 Montreal Protocol and its amendments, ozone-depleting chlorine (and bromine) in the stratosphere has declined slowly since the late 1990s. Improved and extended long-term ozone profile observations from satellites and ground-based stations confirm that ozone is responding as expected and has increased by about 2 % per decade since 2000 in the upper stratosphere, around 40 km altitude. At lower altitudes, however, ozone has not changed significantly since 2000.
Lorena Moreira, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 10259–10268, https://doi.org/10.5194/acp-17-10259-2017, https://doi.org/10.5194/acp-17-10259-2017, 2017
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the Network for the Detection of Atmospheric Composition Change since 1994. A new retrieval version for ozone profiles aims to improve the altitude range of profiles. We performed a comparison between coincident profiles of GROMOS and Aura MLS, resulting in agreement within 2% in
the mid- and upper stratosphere from 2009 to 2016. We also observed extensions of the tertiary ozone maximum at midlatitudes.
Klemens Hocke, Franziska Schranz, Eliane Maillard Barras, Lorena Moreira, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 3445–3452, https://doi.org/10.5194/acp-17-3445-2017, https://doi.org/10.5194/acp-17-3445-2017, 2017
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Observation and simulation show an Atlantic ozone streamer along the edge region of the polar vortex in the northern middle stratosphere during winter. The Atlantic streamer has wind speeds of about 100 m/s and turns equatorward at a vortex erosion region. We compare the fields of stratospheric ozone and water vapour from ground- and space-based microwave radiometry and SD-WACCM simulations for a better understanding of non-linear transport processes in the middle atmosphere.
Klemens Hocke, Martin Lainer, Lorena Moreira, Jonas Hagen, Susana Fernandez Vidal, and Franziska Schranz
Ann. Geophys., 34, 781–788, https://doi.org/10.5194/angeo-34-781-2016, https://doi.org/10.5194/angeo-34-781-2016, 2016
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The dense horizontal sampling of atmospheric temperature profiles by the microwave limb sounder MLS on the NASA satellite AURA permit the estimation of global distributions of inertia-gravity waves (IGWs) in the middle atmosphere. We present and discuss the estimated global distributions of IGWs for July 2015 and January 2016. A dependence on the zonal wind distribution is obvious. The distributions of IGWs are a bit similar to the global distributions of small-scale gravity waves.
Lorena Moreira, Klemens Hocke, Francisco Navas-Guzmán, Ellen Eckert, Thomas von Clarmann, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 10455–10467, https://doi.org/10.5194/acp-16-10455-2016, https://doi.org/10.5194/acp-16-10455-2016, 2016
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The GROMOS radiometer in Bern has been part of the NDACC since 1994. Our time series of stratospheric ozone profiles allow the assessment of natural oscillations, which are essential for the evaluation of detected stratospheric ozone trends. Among our new findings are the link between the upper stratospheric O3-SAO and the polar stratopause warmings in winter. We have also detected a strong peak amplitude of 5 % related to the solar activity cycle and the ENSO effect in ozone at midlatitudes.
Rolf Rüfenacht, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 4915–4925, https://doi.org/10.5194/acp-16-4915-2016, https://doi.org/10.5194/acp-16-4915-2016, 2016
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We quantitatively analyze oscillations with periods from 5 to 50 days in horizontal wind profiles between mid-stratosphere and mesopause based on more than 44 months of data from high, mid- and low latitudes measured by a novel instrument. For the first time, long time series of continuous wind measurements allow direct observations of dynamics throughout this altitude range. The observations agree remarkably well with the ECMWF model in the stratosphere but discrepancies exist in the mesosphere.
L. Moreira, K. Hocke, E. Eckert, T. von Clarmann, and N. Kämpfer
Atmos. Chem. Phys., 15, 10999–11009, https://doi.org/10.5194/acp-15-10999-2015, https://doi.org/10.5194/acp-15-10999-2015, 2015
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the NDACC (Network for the Detection of Atmospheric Composition Change) at Bern since 1994. We performed a trend analysis of our 20-year time series of stratospheric ozone profiles with a multilinear parametric trend estimation method. With our estimated ozone trends we are able to support the stratospheric ozone turnaround, besides a statistically significant negative trend in the lower mesosphere.
K. Hocke, M. Lainer, and A. Schanz
Ann. Geophys., 33, 783–788, https://doi.org/10.5194/angeo-33-783-2015, https://doi.org/10.5194/angeo-33-783-2015, 2015
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The composite analysis of major sudden stratospheric warmings (SSW) showed changes in atmospheric parameters at mid-latitudes about 1-2 months before the central date of the SSW. Polar ozone is enhanced during the half year after the SSW event.
A. Schanz, K. Hocke, N. Kämpfer, S. Chabrillat, A. Inness, M. Palm, J. Notholt, I. Boyd, A. Parrish, and Y. Kasai
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-14-32667-2014, https://doi.org/10.5194/acpd-14-32667-2014, 2014
Revised manuscript not accepted
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The manuscript describes novel findings in the diurnal variation of stratospheric ozone by means of the MACC reanalysis, the ERA-Interim reanalysis and the WACCM model. The diurnal variation in ozone has dynamical and photochemical origins which lead to substantial amplitudes especially in the polar, stratospheric regions. The unprecedented, global view on diurnal ozone variation strengthens the implication to correct diurnally sampled satellite observations used for ozone trend estimates.
A. Schanz, K. Hocke, and N. Kämpfer
Atmos. Chem. Phys., 14, 7645–7663, https://doi.org/10.5194/acp-14-7645-2014, https://doi.org/10.5194/acp-14-7645-2014, 2014
D. Scheiben, B. Tschanz, K. Hocke, N. Kämpfer, S. Ka, and J. J. Oh
Atmos. Chem. Phys., 14, 6511–6522, https://doi.org/10.5194/acp-14-6511-2014, https://doi.org/10.5194/acp-14-6511-2014, 2014
S. Studer, K. Hocke, A. Schanz, H. Schmidt, and N. Kämpfer
Atmos. Chem. Phys., 14, 5905–5919, https://doi.org/10.5194/acp-14-5905-2014, https://doi.org/10.5194/acp-14-5905-2014, 2014
F. Cossu and K. Hocke
Geosci. Model Dev., 7, 147–160, https://doi.org/10.5194/gmd-7-147-2014, https://doi.org/10.5194/gmd-7-147-2014, 2014
S. Studer, K. Hocke, M. Pastel, S. Godin-Beekmann, and N. Kämpfer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amtd-6-6097-2013, https://doi.org/10.5194/amtd-6-6097-2013, 2013
Revised manuscript has not been submitted
K. Hocke, S. Studer, O. Martius, D. Scheiben, and N. Kämpfer
Ann. Geophys., 31, 755–764, https://doi.org/10.5194/angeo-31-755-2013, https://doi.org/10.5194/angeo-31-755-2013, 2013
Guanyi Ma and Klemens Hocke
EGUsphere, https://doi.org/10.5194/egusphere-2024-3177, https://doi.org/10.5194/egusphere-2024-3177, 2024
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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We analyze the influences of sudden stratospheric warming (SSW) on diurnal/semidiurnal variations of ionosphere with the global total electron content (TEC) from 1998 to 2022. We use machine learning (ML) to establish the TEC (ML-TEC) model related to the solar/geomagnetic activities and seasonal change from the TEC data. Subtracting the ML-TEC from the observed TEC, we find a globally SSW-induced enhancement in diurnal/semidiurnal TEC variations.
Huixin Liu
Hist. Geo Space. Sci., 15, 41–42, https://doi.org/10.5194/hgss-15-41-2024, https://doi.org/10.5194/hgss-15-41-2024, 2024
Maria Gloria Tan Jun Rios, Claudia Borries, Huixin Liu, and Jens Mielich
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-11, https://doi.org/10.5194/angeo-2024-11, 2024
Revised manuscript accepted for ANGEO
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The study analyzes hourly NmF2 data from Juliusruh (1957 to 2023) and examines the response of NmF2 to solar flux by using three different solar EUV proxies for six solar cycles, including a separation of the ascending and descending phases. The response is better represented with a quadratic regression and F30 shows the highest correlation for describing NmF2 dependence over time. These results revealed a steady decrease in NmF2, influenced by the intensity of the solar activity index.
Klemens Hocke, Wenyue Wang, and Guanyi Ma
Atmos. Chem. Phys., 24, 5837–5846, https://doi.org/10.5194/acp-24-5837-2024, https://doi.org/10.5194/acp-24-5837-2024, 2024
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We find a sudden stratospheric warming (SSW) effect in the F2 critical frequency (foF2) series for Okinawa. Across 29 SSW events, the amplitude of the semidiurnal cycle of foF2 peaks at the SSW onset in the SSW years. In these years, we find, for the first time, a lunar terdiurnal component with a relative amplitude of about 5 %, and lunar diurnal and semidiurnal components have relative amplitudes of about 10 %. The periods of lunar ionospheric tidal variations align with those of ocean tides.
Juliana Jaen, Toralf Renkwitz, Huixin Liu, Christoph Jacobi, Robin Wing, Aleš Kuchař, Masaki Tsutsumi, Njål Gulbrandsen, and Jorge L. Chau
Atmos. Chem. Phys., 23, 14871–14887, https://doi.org/10.5194/acp-23-14871-2023, https://doi.org/10.5194/acp-23-14871-2023, 2023
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Investigation of winds is important to understand atmospheric dynamics. In the summer mesosphere and lower thermosphere, there are three main wind flows: the mesospheric westward, the mesopause southward (equatorward), and the lower-thermospheric eastward wind. Combining almost 2 decades of measurements from different radars, we study the trend, their interannual oscillations, and the effects of the geomagnetic activity over these wind maxima.
Qiong Tang, Chen Zhou, Huixin Liu, Yi Liu, Jiaqi Zhao, Zhibin Yu, Zhengyu Zhao, and Xueshang Feng
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-534, https://doi.org/10.5194/acp-2022-534, 2022
Preprint withdrawn
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The geomagnetic and solar effect on Es is studied. The negative correlation between Es and geomagnetic activity at mid-latitude is related to the decreased meteor rate during storm period. The increased Es occurrence in high latitude relates to the changing electric field. The positive correlation between Es and solar activity at high latitude is due to the enhanced IMF in solar maximum. The negative correlation in mid and low latitudes relates to the decreased meteor rate during solar activity.
Phoebe Noble, Neil Hindley, Corwin Wright, Chihoko Cullens, Scott England, Nicholas Pedatella, Nicholas Mitchell, and Tracy Moffat-Griffin
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-150, https://doi.org/10.5194/acp-2022-150, 2022
Revised manuscript not accepted
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We use long term radar data and the WACCM-X model to study the impact of dynamical phenomena, including the 11-year solar cycle, ENSO, QBO and SAM, on Antarctic mesospheric winds. We find that in summer, the zonal wind (both observationally and in the model) is strongly correlated with the solar cycle. We also see important differences in the results from the other processes. In addition we find important and large biases in the winter model zonal winds relative to the observations.
John P. McCormack, V. Lynn Harvey, Cora E. Randall, Nicholas Pedatella, Dai Koshin, Kaoru Sato, Lawrence Coy, Shingo Watanabe, Fabrizio Sassi, and Laura A. Holt
Atmos. Chem. Phys., 21, 17577–17605, https://doi.org/10.5194/acp-21-17577-2021, https://doi.org/10.5194/acp-21-17577-2021, 2021
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In order to have confidence in atmospheric predictions, it is important to know how well different numerical model simulations of the Earth’s atmosphere agree with one another. This work compares four different data assimilation models that extend to or beyond the mesosphere. Results shown here demonstrate that while the models are in close agreement below ~50 km, large differences arise at higher altitudes in the mesosphere and lower thermosphere that will need to be reconciled in the future.
Gunter Stober, Ales Kuchar, Dimitry Pokhotelov, Huixin Liu, Han-Li Liu, Hauke Schmidt, Christoph Jacobi, Kathrin Baumgarten, Peter Brown, Diego Janches, Damian Murphy, Alexander Kozlovsky, Mark Lester, Evgenia Belova, Johan Kero, and Nicholas Mitchell
Atmos. Chem. Phys., 21, 13855–13902, https://doi.org/10.5194/acp-21-13855-2021, https://doi.org/10.5194/acp-21-13855-2021, 2021
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Little is known about the climate change of wind systems in the mesosphere and lower thermosphere at the edge of space at altitudes from 70–110 km. Meteor radars represent a well-accepted remote sensing technique to measure winds at these altitudes. Here we present a state-of-the-art climatological interhemispheric comparison using continuous and long-lasting observations from worldwide distributed meteor radars from the Arctic to the Antarctic and sophisticated general circulation models.
Leonie Bernet, Elmar Brockmann, Thomas von Clarmann, Niklaus Kämpfer, Emmanuel Mahieu, Christian Mätzler, Gunter Stober, and Klemens Hocke
Atmos. Chem. Phys., 20, 11223–11244, https://doi.org/10.5194/acp-20-11223-2020, https://doi.org/10.5194/acp-20-11223-2020, 2020
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With global warming, water vapour increases in the atmosphere. Water vapour is an important gas because it is a natural greenhouse gas and affects the formation of clouds, rain and snow. How much water vapour increases can vary in different regions of the world. To verify if it increases as expected on a regional scale, we analysed water vapour measurements in Switzerland. We found that water vapour generally increases as expected from temperature changes, except in winter.
Franziska Schranz, Jonas Hagen, Gunter Stober, Klemens Hocke, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 10791–10806, https://doi.org/10.5194/acp-20-10791-2020, https://doi.org/10.5194/acp-20-10791-2020, 2020
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We measured middle-atmospheric ozone, water vapour and zonal and meridional wind with two ground-based microwave radiometers which are located at Ny-Alesund, Svalbard, in the Arctic. In this article we present measurements of the small-scale horizontal ozone gradients during winter 2018/2019. We found a distinct seasonal variation of the ozone gradients which is linked to the planetary wave activity. We further present the signatures of the SSW in the ozone, water vapour and wind measurements.
Eliane Maillard Barras, Alexander Haefele, Liliane Nguyen, Fiona Tummon, William T. Ball, Eugene V. Rozanov, Rolf Rüfenacht, Klemens Hocke, Leonie Bernet, Niklaus Kämpfer, Gerald Nedoluha, and Ian Boyd
Atmos. Chem. Phys., 20, 8453–8471, https://doi.org/10.5194/acp-20-8453-2020, https://doi.org/10.5194/acp-20-8453-2020, 2020
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To determine the part of the variability of the long-term ozone profile trends coming from measurement timing, we estimate microwave radiometer trends for each hour of the day with a multiple linear regression model. The variation in the trend with local solar time is not significant at the 95 % confidence level either in the stratosphere or in the low mesosphere. We conclude that systematic sampling differences between instruments cannot explain significant differences in trend estimates.
Jonas Hagen, Klemens Hocke, Gunter Stober, Simon Pfreundschuh, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 2367–2386, https://doi.org/10.5194/acp-20-2367-2020, https://doi.org/10.5194/acp-20-2367-2020, 2020
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The middle atmosphere (30 to 70 km altitude) is stratified and, despite very strong horizontal winds, there is less mixing between the horizontal layers. An important driver for the energy exchange between the layers in this regime is atmospheric tides, which are waves that are driven by the diurnal cycle of solar heating. We measure these tides in the wind field for the first time using a ground-based passive instrument. Ultimately, such measurements could be used to improve atmospheric models.
Philippe Baron, Satoshi Ochiai, Eric Dupuy, Richard Larsson, Huixin Liu, Naohiro Manago, Donal Murtagh, Shin-ichiro Oyama, Hideo Sagawa, Akinori Saito, Takatoshi Sakazaki, Masato Shiotani, and Makoto Suzuki
Atmos. Meas. Tech., 13, 219–237, https://doi.org/10.5194/amt-13-219-2020, https://doi.org/10.5194/amt-13-219-2020, 2020
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Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2) is a satellite mission proposed in Japan to probe the middle and upper atmosphere (20–160 km). The key products are wind, temperature and density. If selected, this mission could provide new insights into vertical coupling in the atmosphere and could help improve weather and climate models. We conducted simulation studies to assess the measurement performances in the altitude range 60–110 km, with a special focus on the geomagnetic effects.
Klemens Hocke, Leonie Bernet, Jonas Hagen, Axel Murk, Matthias Renker, and Christian Mätzler
Atmos. Chem. Phys., 19, 12083–12090, https://doi.org/10.5194/acp-19-12083-2019, https://doi.org/10.5194/acp-19-12083-2019, 2019
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The Tropospheric Water Radiometer (TROWARA) observed an enhanced intensity of short-term integrated water vapour (IWV) fluctuations during daytime in summer. These IWV fluctuations are possibly related to latent heat flux and thermal convective activity in the lower troposphere. The observed climatology and spectra of IWV fluctuations might be useful for modelling studies of water vapour convection in the atmospheric boundary layer at mid latitudes.
Franziska Schranz, Brigitte Tschanz, Rolf Rüfenacht, Klemens Hocke, Mathias Palm, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 9927–9947, https://doi.org/10.5194/acp-19-9927-2019, https://doi.org/10.5194/acp-19-9927-2019, 2019
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The dynamics of the Arctic middle atmosphere above Ny-Ålesund, Svalbard (79° N, 12° E) is investigated using 3 years of H2O and O3 measurements from ground-based microwave radiometers. We found the signals of atmospheric phenomena like sudden stratospheric warmings, polar vortex shifts, effective descent rates of water vapour and periodicities in our data. Additionally, a comprehensive intercomparison is performed with models and measurements from ground-based, in situ and satellite instruments.
Klemens Hocke, Jonas Hagen, Franziska Schranz, and Leonie Bernet
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2019-630, https://doi.org/10.5194/acp-2019-630, 2019
Preprint withdrawn
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The dense sampling of geopotential height (GPH) profiles of the microwave limb sounder (MLS) on NASA's satellite Aura is appropriate for detection of mesospheric gravity waves. Up to now, the global distribution of mesospheric gravity wave activity is relatively unknown. The study focuses on the relation of mesospheric gravity waves to major sudden stratospheric warmings.
Martin Lainer, Klemens Hocke, Ellen Eckert, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 6611–6620, https://doi.org/10.5194/acp-19-6611-2019, https://doi.org/10.5194/acp-19-6611-2019, 2019
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A middle atmospheric water vapor time series of more than 11 years (April 2007 to May 2018) from the NDACC microwave remote sensing site at Bern (Switzerland) is investigated to estimate the trend by means of a robust multilinear parametric trend model. Between 61 and 72 km altitude a significant decline in water vapor could be detected. The reduction of water vapor maximizes to about −12 % per decade at 72 km altitude.
Jinghua Li, Guanyi Ma, Klemens Hocke, Qingtao Wan, Jiangtao Fan, and Xiaolan Wang
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2019-64, https://doi.org/10.5194/angeo-2019-64, 2019
Revised manuscript not accepted
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Local occurrence rate (LOR) is defined to clarify the characteristics of ionospheric irregularities together with monthly occurrence rate (MOR) at 20–29° N in solar minimum, medium and maximum years of 2008, 2003 and 2014. MOR of irregularities in May/June is larger than that in equinoxes, which is different with the equatorial plasma bubbles. LOR shows that the irregularities at 26–29° N in May/June are more frequently happened and have smaller spatiotemporal scales than those at lower latitudes.
Fazlul I. Laskar, Gunter Stober, Jens Fiedler, Meers M. Oppenheim, Jorge L. Chau, Duggirala Pallamraju, Nicholas M. Pedatella, Masaki Tsutsumi, and Toralf Renkwitz
Atmos. Chem. Phys., 19, 5259–5267, https://doi.org/10.5194/acp-19-5259-2019, https://doi.org/10.5194/acp-19-5259-2019, 2019
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Meteor radars are used to track and estimate the fading time of meteor trails. In this investigation, it is observed that the diffusion time estimated from such trail fading time is anomalously higher during noctilucent clouds (NLC) than that in its absence. We propose that NLC particles absorb background electrons and thus modify the background electrodynamics, leading to such an anomaly.
Leonie Bernet, Thomas von Clarmann, Sophie Godin-Beekmann, Gérard Ancellet, Eliane Maillard Barras, René Stübi, Wolfgang Steinbrecht, Niklaus Kämpfer, and Klemens Hocke
Atmos. Chem. Phys., 19, 4289–4309, https://doi.org/10.5194/acp-19-4289-2019, https://doi.org/10.5194/acp-19-4289-2019, 2019
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After severe ozone depletion, upper stratospheric ozone has started to recover in recent years. However, stratospheric ozone trends from various data sets still show differences. To partly explain such differences, we investigate how the trends are affected by different factors, for example, anomalies in the data. We show how trend estimates can be improved by considering such anomalies and present updated stratospheric ozone trends from ground data measured in central Europe.
Tarique A. Siddiqui, Astrid Maute, Nick Pedatella, Yosuke Yamazaki, Hermann Lühr, and Claudia Stolle
Ann. Geophys., 36, 1545–1562, https://doi.org/10.5194/angeo-36-1545-2018, https://doi.org/10.5194/angeo-36-1545-2018, 2018
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Extreme meteorological events such as SSWs induce variabilities in the ionosphere by modulating the atmospheric tides, and these variabilities can be comparable to a moderate geomagnetic storm. The equatorial electrojet (EEJ) is a narrow ribbon of current flowing over the dip equator in the ionosphere and is particularly sensitive to tidal changes. In this study, we use ground-magnetic measurements to investigate the semidiurnal solar and lunar tidal variabilities of the EEJ during SSWs.
Martin Lainer, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 18, 12061–12074, https://doi.org/10.5194/acp-18-12061-2018, https://doi.org/10.5194/acp-18-12061-2018, 2018
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A long continuous record (in total 7 years) of middle atmospheric water vapor at the midlatitude NDACC station in Bern is investigated to study quasi 2-day wave oscillations (Q2DWs). We present monthly climatologies of the wave amplitudes and show the periods that the Q2DWs developed. What we observe is very-high-frequency variability. An autobicoherence analysis revealed nonlinear phase couplings between Q2DWs and other atmospheric waves. Our results are useful for model validation purposes.
Martin Lainer, Klemens Hocke, Rolf Rüfenacht, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 14905–14917, https://doi.org/10.5194/acp-17-14905-2017, https://doi.org/10.5194/acp-17-14905-2017, 2017
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We report on middle-atmospheric water vapor measurements above Bern from the ground-based microwave radiometer MIAWARA (NDACC affiliated) during two winter periods of 6 months. Quasi 18 h oscillations of mesospheric water vapor above 0.1 hPa are observed. Further, the 18 h wave is seen in a zonal wind data set from the Doppler wind radiometer WIRA. Inertia-gravity-wave-induced fluctuations or a nonlinear coupling between tides and quasi 2-day waves are considered as possible drivers.
Klemens Hocke, Francisco Navas-Guzmán, Lorena Moreira, Leonie Bernet, and Christian Mätzler
Atmos. Chem. Phys., 17, 12121–12131, https://doi.org/10.5194/acp-17-12121-2017, https://doi.org/10.5194/acp-17-12121-2017, 2017
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We derive the annual and semi-annual oscillations in cloud fraction (CF), integrated liquid water (ILW) and integrated water vapour (IWV) from the long-term measurements of the TROWARA radiometer in Bern, Switzerland. Further, we find a weekly cycle of CF and ILW from June to September with increased values on Saturday, Sunday and Monday.
Wolfgang Steinbrecht, Lucien Froidevaux, Ryan Fuller, Ray Wang, John Anderson, Chris Roth, Adam Bourassa, Doug Degenstein, Robert Damadeo, Joe Zawodny, Stacey Frith, Richard McPeters, Pawan Bhartia, Jeannette Wild, Craig Long, Sean Davis, Karen Rosenlof, Viktoria Sofieva, Kaley Walker, Nabiz Rahpoe, Alexei Rozanov, Mark Weber, Alexandra Laeng, Thomas von Clarmann, Gabriele Stiller, Natalya Kramarova, Sophie Godin-Beekmann, Thierry Leblanc, Richard Querel, Daan Swart, Ian Boyd, Klemens Hocke, Niklaus Kämpfer, Eliane Maillard Barras, Lorena Moreira, Gerald Nedoluha, Corinne Vigouroux, Thomas Blumenstock, Matthias Schneider, Omaira García, Nicholas Jones, Emmanuel Mahieu, Dan Smale, Michael Kotkamp, John Robinson, Irina Petropavlovskikh, Neil Harris, Birgit Hassler, Daan Hubert, and Fiona Tummon
Atmos. Chem. Phys., 17, 10675–10690, https://doi.org/10.5194/acp-17-10675-2017, https://doi.org/10.5194/acp-17-10675-2017, 2017
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Thanks to the 1987 Montreal Protocol and its amendments, ozone-depleting chlorine (and bromine) in the stratosphere has declined slowly since the late 1990s. Improved and extended long-term ozone profile observations from satellites and ground-based stations confirm that ozone is responding as expected and has increased by about 2 % per decade since 2000 in the upper stratosphere, around 40 km altitude. At lower altitudes, however, ozone has not changed significantly since 2000.
Lorena Moreira, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 10259–10268, https://doi.org/10.5194/acp-17-10259-2017, https://doi.org/10.5194/acp-17-10259-2017, 2017
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the Network for the Detection of Atmospheric Composition Change since 1994. A new retrieval version for ozone profiles aims to improve the altitude range of profiles. We performed a comparison between coincident profiles of GROMOS and Aura MLS, resulting in agreement within 2% in
the mid- and upper stratosphere from 2009 to 2016. We also observed extensions of the tertiary ozone maximum at midlatitudes.
Klemens Hocke, Franziska Schranz, Eliane Maillard Barras, Lorena Moreira, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 3445–3452, https://doi.org/10.5194/acp-17-3445-2017, https://doi.org/10.5194/acp-17-3445-2017, 2017
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Observation and simulation show an Atlantic ozone streamer along the edge region of the polar vortex in the northern middle stratosphere during winter. The Atlantic streamer has wind speeds of about 100 m/s and turns equatorward at a vortex erosion region. We compare the fields of stratospheric ozone and water vapour from ground- and space-based microwave radiometry and SD-WACCM simulations for a better understanding of non-linear transport processes in the middle atmosphere.
Klemens Hocke, Martin Lainer, Lorena Moreira, Jonas Hagen, Susana Fernandez Vidal, and Franziska Schranz
Ann. Geophys., 34, 781–788, https://doi.org/10.5194/angeo-34-781-2016, https://doi.org/10.5194/angeo-34-781-2016, 2016
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The dense horizontal sampling of atmospheric temperature profiles by the microwave limb sounder MLS on the NASA satellite AURA permit the estimation of global distributions of inertia-gravity waves (IGWs) in the middle atmosphere. We present and discuss the estimated global distributions of IGWs for July 2015 and January 2016. A dependence on the zonal wind distribution is obvious. The distributions of IGWs are a bit similar to the global distributions of small-scale gravity waves.
Lorena Moreira, Klemens Hocke, Francisco Navas-Guzmán, Ellen Eckert, Thomas von Clarmann, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 10455–10467, https://doi.org/10.5194/acp-16-10455-2016, https://doi.org/10.5194/acp-16-10455-2016, 2016
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The GROMOS radiometer in Bern has been part of the NDACC since 1994. Our time series of stratospheric ozone profiles allow the assessment of natural oscillations, which are essential for the evaluation of detected stratospheric ozone trends. Among our new findings are the link between the upper stratospheric O3-SAO and the polar stratopause warmings in winter. We have also detected a strong peak amplitude of 5 % related to the solar activity cycle and the ENSO effect in ozone at midlatitudes.
Rolf Rüfenacht, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 4915–4925, https://doi.org/10.5194/acp-16-4915-2016, https://doi.org/10.5194/acp-16-4915-2016, 2016
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We quantitatively analyze oscillations with periods from 5 to 50 days in horizontal wind profiles between mid-stratosphere and mesopause based on more than 44 months of data from high, mid- and low latitudes measured by a novel instrument. For the first time, long time series of continuous wind measurements allow direct observations of dynamics throughout this altitude range. The observations agree remarkably well with the ECMWF model in the stratosphere but discrepancies exist in the mesosphere.
L. Moreira, K. Hocke, E. Eckert, T. von Clarmann, and N. Kämpfer
Atmos. Chem. Phys., 15, 10999–11009, https://doi.org/10.5194/acp-15-10999-2015, https://doi.org/10.5194/acp-15-10999-2015, 2015
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the NDACC (Network for the Detection of Atmospheric Composition Change) at Bern since 1994. We performed a trend analysis of our 20-year time series of stratospheric ozone profiles with a multilinear parametric trend estimation method. With our estimated ozone trends we are able to support the stratospheric ozone turnaround, besides a statistically significant negative trend in the lower mesosphere.
K. Hocke, M. Lainer, and A. Schanz
Ann. Geophys., 33, 783–788, https://doi.org/10.5194/angeo-33-783-2015, https://doi.org/10.5194/angeo-33-783-2015, 2015
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The composite analysis of major sudden stratospheric warmings (SSW) showed changes in atmospheric parameters at mid-latitudes about 1-2 months before the central date of the SSW. Polar ozone is enhanced during the half year after the SSW event.
A. Schanz, K. Hocke, N. Kämpfer, S. Chabrillat, A. Inness, M. Palm, J. Notholt, I. Boyd, A. Parrish, and Y. Kasai
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-14-32667-2014, https://doi.org/10.5194/acpd-14-32667-2014, 2014
Revised manuscript not accepted
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The manuscript describes novel findings in the diurnal variation of stratospheric ozone by means of the MACC reanalysis, the ERA-Interim reanalysis and the WACCM model. The diurnal variation in ozone has dynamical and photochemical origins which lead to substantial amplitudes especially in the polar, stratospheric regions. The unprecedented, global view on diurnal ozone variation strengthens the implication to correct diurnally sampled satellite observations used for ozone trend estimates.
C. H. Lin, J. T. Lin, C. H. Chen, J. Y. Liu, Y. Y. Sun, Y. Kakinami, M. Matsumura, W. H. Chen, H. Liu, and R. J. Rau
Ann. Geophys., 32, 1145–1152, https://doi.org/10.5194/angeo-32-1145-2014, https://doi.org/10.5194/angeo-32-1145-2014, 2014
A. Schanz, K. Hocke, and N. Kämpfer
Atmos. Chem. Phys., 14, 7645–7663, https://doi.org/10.5194/acp-14-7645-2014, https://doi.org/10.5194/acp-14-7645-2014, 2014
D. Scheiben, B. Tschanz, K. Hocke, N. Kämpfer, S. Ka, and J. J. Oh
Atmos. Chem. Phys., 14, 6511–6522, https://doi.org/10.5194/acp-14-6511-2014, https://doi.org/10.5194/acp-14-6511-2014, 2014
S. Studer, K. Hocke, A. Schanz, H. Schmidt, and N. Kämpfer
Atmos. Chem. Phys., 14, 5905–5919, https://doi.org/10.5194/acp-14-5905-2014, https://doi.org/10.5194/acp-14-5905-2014, 2014
F. Cossu and K. Hocke
Geosci. Model Dev., 7, 147–160, https://doi.org/10.5194/gmd-7-147-2014, https://doi.org/10.5194/gmd-7-147-2014, 2014
S. Studer, K. Hocke, M. Pastel, S. Godin-Beekmann, and N. Kämpfer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amtd-6-6097-2013, https://doi.org/10.5194/amtd-6-6097-2013, 2013
Revised manuscript has not been submitted
K. Hocke, S. Studer, O. Martius, D. Scheiben, and N. Kämpfer
Ann. Geophys., 31, 755–764, https://doi.org/10.5194/angeo-31-755-2013, https://doi.org/10.5194/angeo-31-755-2013, 2013
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
Occurrence climatology of equatorial plasma bubbles derived using FormoSat-3 ∕ COSMIC GPS radio occultation data
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
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.
Ankur Kepkar, Christina Arras, Jens Wickert, Harald Schuh, Mahdi Alizadeh, and Lung-Chih Tsai
Ann. Geophys., 38, 611–623, https://doi.org/10.5194/angeo-38-611-2020, https://doi.org/10.5194/angeo-38-611-2020, 2020
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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.
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.
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.
Cited articles
Aarons, J.: Global morphology of ionospheric scintillations, IEEE
Proceedings, 70, 360–378, 1982. a
Anthes, R. A., Bernhardt, P. A., Chen, Y., Cucurull, L., Dymond,
K. F., Ector, D., Healy, S. B., Ho, S.-P., Hunt, D. C., Kuo, Y.-H.,
Liu, H., Manning, K., McCormick, C., Meehan, T. K., Randel, W. J.,
Rocken, C., Schreiner, W. S., Sokolovskiy, S. V., Syndergaard, S.,
Thompson, D. C., Trenberth, K. E., Wee, T.-K., Yen, N. L., and
Zeng, Z.: The COSMIC/FORMOSAT-3 Mission: Early Results, B.
Am. Meteorol. Soc., 89, 313–334, https://doi.org/10.1175/BAMS-89-3-313, 2008. a
Arras, C., Jacobi, C., Wickert, J., Heise, S., and Schmidt, T.: Sporadic E
signatures revealed from multi-satellite radio occultation measurements, Adv.
Radio Sci., 8, 225–230, https://doi.org/10.5194/ars-8-225-2010, 2010. a
Carter, B. A., Zhang, K., Norman, R., Kumar, V. V., and Kumar, S.: On the
occurrence of equatorial F-region irregularities during solar minimum using
radio occultation measurements, J. Geophys. Res.-Space, 118, 892–904, https://doi.org/10.1002/jgra.50089, 2013. a, b
Cherniak, I. and Zakharenkova, I.: New advantages of the combined GPS
and
GLONASS observations for high-latitude ionospheric irregularities monitoring:
case study of June 2015 geomagnetic storm, Earth Planets Space, 69,
66, https://doi.org/10.1186/s40623-017-0652-0, 2017. a
Fejer, B. G. and Kelley, M. C.: Ionospheric irregularities, Rev.
Geophys. Space Ge., 18, 401–454, https://doi.org/10.1029/RG018i002p00401,
1980. a, b, c, d
Hajj, G. A., Kursinski, E. R., Romans, L. J., Bertiger, W. I., and
Leroy, S. S.: A technical description of atmospheric sounding by GPS
occultation, J. Atmos. Sol.-Terr. Phy., 64,
451–469, https://doi.org/10.1016/S1364-6826(01)00114-6, 2002. a
Hocke, K., Igarashi, K., Nakamura, M., Wilkinson, P., Wu, J.,
Pavelyev, A., and Wickert, J.: Global sounding of sporadic E layers by
the GPS/MET radio occultation experiment, J. Atmos.
Sol.-Terr. Phy., 63, 1973–1980,
https://doi.org/10.1016/S1364-6826(01)00063-3, 2001. a
Hocke, K., Igarashi, K., and Pavelyev, A.: Irregularities of the topside
ionosphere observed by GPS/MET radio occultation, Radio Sci., 37,
13-1–13-11, https://doi.org/10.1029/2001RS002599, 2002.
a
Rocken, C., Anthes, R., Exner, M., Hunt, D., Sokolovskiy, S.,
Ware,
R., Gorbunov, M., Schreiner, W., Feng, D., Herman, B., Kuo, Y.-H.,
and Zou, X.: Analysis and validation of GPS/MET data in the neutral
atmosphere, J. Geophys. Res., 102, 29849–29866,
https://doi.org/10.1029/97JD02400, 1997. a
Studer, S., Hocke, K., and Kämpfer, N.: Intraseasonal oscillations of
stratospheric ozone above Switzerland, J. Atmos.
Sol.-Terr. Phy., 74, 189–198, 2012. a
Tsunoda, R. T.: Time evolution and dynamics of equatorial backscatter
plumes. I – Growth phase, J. Geophys. Res., 86, 139–149,
https://doi.org/10.1029/JA086iA01p00139, 1981. a, b, c
Tsunoda, R. T., Saito, S., and Nguyen, T. T.: Post-sunset rise of equatorial
F
layer – or upwelling growth?, Prog. Earth Planet. Sc., 5, 22,
https://doi.org/10.1186/s40645-018-0179-4, 2018. a
Wang, M., Lou, W., Li, P., Shen, X., and Li, Q.: Monitoring the ionospheric
storm effect with multiple instruments in North China: July 15–16, 2012
magnetic storm event, J. Atmos. Sol.-Terr. Phy.,
102, 261–268, https://doi.org/10.1016/j.jastp.2013.05.021,
2013. a
Watson, C. and Pedatella, N. M.: Climatology and Characteristics of
Medium-Scale F Region Ionospheric Plasma Irregularities Observed by COSMIC
Radio Occultation Receivers, J. Geophys. Res.-Space,
123, 8610–8630, https://doi.org/10.1029/2018JA025696, 2018. a, b, c
Wu, D. L., Ao, C. O., Hajj, G. A., de La Torre Juarez, M., and
Mannucci, A. J.: Sporadic E morphology from GPS-CHAMP radio occultation,
J. Geophys. Res.-Space, 110, A01306,
https://doi.org/10.1029/2004JA010701, 2005. a
Zakharenkova, I. and Astafyeva, E.: Topside ionospheric irregularities as
seen from multisatellite observations, J. Geophys. Res.-Space, 120, 807–824,
https://doi.org/10.1002/2014JA020330, 2015. a, b
Short summary
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.
The GPS radio occultation data of the COSMIC-FORMOSAT-3 mission are used to visualize the global...