Articles | Volume 13, issue 18
https://doi.org/10.5194/acp-13-9515-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/acp-13-9515-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
27 Sep 2013
Research article |
| 27 Sep 2013
Mean winds in the MLT, the SQBO and MSAO over Ascension Island (8° S, 14° W)
K. A. Day
Centre for Space, Atmospheric and Oceanic Science, Department of Electronic and Electrical Engineering, the University of Bath, Bath, BA2 7AY, UK
Met Office, Exeter, EX1 3PB, UK
N. J. Mitchell
Centre for Space, Atmospheric and Oceanic Science, Department of Electronic and Electrical Engineering, the University of Bath, Bath, BA2 7AY, UK
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Neil P. Hindley, Nicholas J. Mitchell, Neil Cobbett, Anne K. Smith, Dave C. Fritts, Diego Janches, Corwin J. Wright, and Tracy Moffat-Griffin
Atmos. Chem. Phys., 22, 9435–9459, https://doi.org/10.5194/acp-22-9435-2022, https://doi.org/10.5194/acp-22-9435-2022, 2022
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We present observations of winds in the mesosphere and lower thermosphere (MLT) from a recently installed meteor radar on the remote island of South Georgia (54° S, 36° W). We characterise mean winds, tides, planetary waves, and gravity waves in the MLT at this location and compare our measured winds with a leading climate model. We find that the observed wintertime winds are unexpectedly reversed from model predictions, probably because of missing impacts of secondary gravity waves in the model.
Matthew J. Griffith, Shaun M. Dempsey, David R. Jackson, Tracy Moffat-Griffin, and Nicholas J. Mitchell
Ann. Geophys., 39, 487–514, https://doi.org/10.5194/angeo-39-487-2021, https://doi.org/10.5194/angeo-39-487-2021, 2021
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There is great scientific interest in extending atmospheric models upwards to include the upper atmosphere. The Met Office’s Unified Model has recently been successfully extended to include this region. Atmospheric tides are an important driver of atmospheric motion at these greater heights. This paper provides a first comparison of winds and tides produced by the new extended model with meteor radar observations, comparing key tidal properties and discussing their similarities and differences.
Neil P. Hindley, Corwin J. Wright, Alan M. Gadian, Lars Hoffmann, John K. Hughes, David R. Jackson, John C. King, Nicholas J. Mitchell, Tracy Moffat-Griffin, Andrew C. Moss, Simon B. Vosper, and Andrew N. Ross
Atmos. Chem. Phys., 21, 7695–7722, https://doi.org/10.5194/acp-21-7695-2021, https://doi.org/10.5194/acp-21-7695-2021, 2021
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One limitation of numerical atmospheric models is spatial resolution. For atmospheric gravity waves (GWs) generated over small mountainous islands, the driving effect of these waves on atmospheric circulations can be underestimated. Here we use a specialised high-resolution model over South Georgia island to compare simulated stratospheric GWs to colocated 3-D satellite observations. We find reasonable model agreement with observations, with some GW amplitudes much larger than expected.
Neil P. Hindley, Corwin J. Wright, Nathan D. Smith, Lars Hoffmann, Laura A. Holt, M. Joan Alexander, Tracy Moffat-Griffin, and Nicholas J. Mitchell
Atmos. Chem. Phys., 19, 15377–15414, https://doi.org/10.5194/acp-19-15377-2019, https://doi.org/10.5194/acp-19-15377-2019, 2019
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In this study, a 3–D Stockwell transform is applied to AIRS–Aqua satellite observations in the first extended 3–D study of stratospheric gravity waves over the Southern Ocean during winter. A dynamic environment is revealed that contains some of the most intense gravity wave sources on Earth. A particularly striking result is a large–scale meridional convergence of gravity wave momentum flux towards latitudes near 60 °S, something which is not normally considered in model parameterisations.
Corwin J. Wright, Neil P. Hindley, Lars Hoffmann, M. Joan Alexander, and Nicholas J. Mitchell
Atmos. Chem. Phys., 17, 8553–8575, https://doi.org/10.5194/acp-17-8553-2017, https://doi.org/10.5194/acp-17-8553-2017, 2017
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We introduce a novel 3-D method of measuring atmospheric gravity waves, based around a 3-D Stockwell transform. Our method lets us measure new properties, including wave intrinsic frequencies and phase and group velocities. We apply it to data from the AIRS satellite instrument over the Southern Andes for two consecutive winters. Our results show clear evidence that the waves measured are primarily orographic in origin, and that their group velocity vectors are focused into the polar night jet.
Neil P. Hindley, Nathan D. Smith, Corwin J. Wright, D. Andrew S. Rees, and Nicholas J. Mitchell
Atmos. Meas. Tech., 9, 2545–2565, https://doi.org/10.5194/amt-9-2545-2016, https://doi.org/10.5194/amt-9-2545-2016, 2016
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Gravity waves are medium-sized momentum-carrying atmospheric waves that nearly all weather and climate models struggle to represent. Thus, the accurate global measurement of gravity-wave properties in the real atmosphere is of key importance. Here we use a new two-dimensional Stockwell transform (2-DST) method to measure key GW properties in 2-D satellite data. We show that our 2-DST approach greatly improves upon current methods, particularly if a new elliptical spectral window is used.
Corwin J. Wright, Neil P. Hindley, Andrew C. Moss, and Nicholas J. Mitchell
Atmos. Meas. Tech., 9, 877–908, https://doi.org/10.5194/amt-9-877-2016, https://doi.org/10.5194/amt-9-877-2016, 2016
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Seven gravity-wave-resolving instruments (satellites, radiosondes and a meteor radar) are used to compare gravity-wave energy and vertical wavelength over the Southern Andes hotspot. Several conclusions are drawn, including that limb sounders and the radar show strong positive correlations. Radiosondes and AIRS weakly anticorrelate with other instruments and we see strong correlations with local stratospheric winds. Short-timescale variability is larger than the seasonal cycle.
Andrew C. Moss, Corwin J. Wright, Robin N. Davis, and Nicholas J. Mitchell
Ann. Geophys., 34, 323–330, https://doi.org/10.5194/angeo-34-323-2016, https://doi.org/10.5194/angeo-34-323-2016, 2016
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Gravity waves are fundamental to the dynamics of the mesosphere. In some years very strong winds are observed in the first phase of the MSAO. It has been proposed that this is due to filtering of ascending gravity waves. We report the first gravity-wave momentum flux observations from the Ascension Island (8° S, 14° W) meteor radar and show that anomalous fluxes were observed during one such event in 2002. Analysis of the underlying winds suggests the wave-filtering hypothesis is not valid.
H. Iimura, D. C. Fritts, D. Janches, W. Singer, and N. J. Mitchell
Ann. Geophys., 33, 1349–1359, https://doi.org/10.5194/angeo-33-1349-2015, https://doi.org/10.5194/angeo-33-1349-2015, 2015
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The quasi-5-day wave at mid- and high-latitudes in the mesosphere and lower-thermosphere was compared between the hemispheres using meteor radar horizontal wind measurements, spanning June 2010 to December 2012. Variances of the quasi-5-day wave showed a wave activity from July to August in both hemispheres and in April 2012 in the Northern Hemisphere and November 2012 in the Southern Hemisphere with unique characteristics at each site.
N. P. Hindley, C. J. Wright, N. D. Smith, and N. J. Mitchell
Atmos. Chem. Phys., 15, 7797–7818, https://doi.org/10.5194/acp-15-7797-2015, https://doi.org/10.5194/acp-15-7797-2015, 2015
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In nearly all GCMs, unresolved gravity wave (GW) drag may cause the southern stratospheric winter polar vortex to break down too late. Here, we characterise GWs in this region of the atmosphere using GPS radio occultation. We find GWs may propagate into the region from other latitudes. We develop a new quantitative wave identification method to learn about regional wave populations. We also find intense GW momentum fluxes over the southern Andes and Antarctic Peninsula GW hot spot.
R. N. Davis, J. Du, A. K. Smith, W. E. Ward, and N. J. Mitchell
Atmos. Chem. Phys., 13, 9543–9564, https://doi.org/10.5194/acp-13-9543-2013, https://doi.org/10.5194/acp-13-9543-2013, 2013
Related subject area
Subject: Dynamics | Research Activity: Remote Sensing | Altitude Range: Mesosphere | Science Focus: Physics (physical properties and processes)
Upper-atmosphere responses to the 2022 Hunga Tonga–Hunga Ha′apai volcanic eruption via acoustic gravity waves and air–sea interaction
Influences of sudden stratospheric warmings on the ionosphere above Okinawa
Gravity waves generated by the Hunga Tonga–Hunga Ha′apai volcanic eruption and their global propagation in the mesosphere/lower thermosphere observed by meteor radars and modeled with the High-Altitude general Mechanistic Circulation Model
Long-term studies of the summer wind in the mesosphere and lower thermosphere at middle and high latitudes over Europe
Progress in investigating long-term trends in the mesosphere, thermosphere, and ionosphere
Aura/MLS observes and SD-WACCM-X simulates the seasonality, quasi-biennial oscillation and El Niño–Southern Oscillation of the migrating diurnal tide driving upper mesospheric CO primarily through vertical advection
Hydroxyl airglow observations for investigating atmospheric dynamics: results and challenges
Signatures of gravity wave-induced instabilities in balloon lidar soundings of polar mesospheric clouds
Sources of concentric gravity waves generated by a moving mesoscale convective system in southern Brazil
How do gravity waves triggered by a typhoon propagate from the troposphere to the upper atmosphere?
Interhemispheric differences of mesosphere–lower thermosphere winds and tides investigated from three whole-atmosphere models and meteor radar observations
The semiannual oscillation (SAO) in the tropical middle atmosphere and its gravity wave driving in reanalyses and satellite observations
Mesospheric gravity wave activity estimated via airglow imagery, multistatic meteor radar, and SABER data taken during the SIMONe–2018 campaign
Interhemispheric transport of metallic ions within ionospheric sporadic E layers by the lower thermospheric meridional circulation
Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems
Gravity-wave-perturbed wind shears derived from SABER temperature observations
Comparative study between ground-based observations and NAVGEM-HA analysis data in the mesosphere and lower thermosphere region
Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 2: Evidence of a quasi-quadrennial oscillation (QQO) in the polar mesosphere
The MATS satellite mission – gravity wave studies by Mesospheric Airglow/Aerosol Tomography and Spectroscopy
Winter 2018 major sudden stratospheric warming impact on midlatitude mesosphere from microwave radiometer measurements
Climatology of the mesopause relative density using a global distribution of meteor radars
Observations of OH airglow from ground, aircraft, and satellite: investigation of wave-like structures before a minor stratospheric warming
Mesospheric semidiurnal tides and near-12 h waves through jointly analyzing observations of five specular meteor radars from three longitudinal sectors at boreal midlatitudes
Statistical climatology of mid-latitude mesospheric summer echoes characterised by OSWIN (Ostsee-Wind) radar observations
Can VHF radars at polar latitudes measure mean vertical winds in the presence of PMSE?
The global climatology of the intensity of the ionospheric sporadic E layer
Long-term lidar observations of the gravity wave activity near the mesopause at Arecibo
Characterization of flow recirculation zones at the Perdigão site using multi-lidar measurements
Solar 27-day signatures in standard phase height measurements above central Europe
Mesospheric bores at southern midlatitudes observed by ISS-IMAP/VISI: a first report of an undulating wave front
Simultaneous observations of NLCs and MSEs at midlatitudes: implications for formation and advection of ice particles
Long-term observation of midlatitude quasi 2-day waves by a water vapor radiometer
Climatology of mesopause region nocturnal temperature, zonal wind and sodium density observed by sodium lidar over Hefei, China (32° N, 117° E)
Multi-static spatial and angular studies of polar mesospheric summer echoes combining MAARSY and KAIRA
Observation of Kelvin–Helmholtz instabilities and gravity waves in the summer mesopause above Andenes in Northern Norway
Temporal variability of tidal and gravity waves during a record long 10-day continuous lidar sounding
Quasi 18 h wave activity in ground-based observed mesospheric H2O over Bern, Switzerland
Winds and temperatures of the Arctic middle atmosphere during January measured by Doppler lidar
Short-period mesospheric gravity waves and their sources at the South Pole
Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations
MIPAS observations of longitudinal oscillations in the mesosphere and the lower thermosphere: climatology of odd-parity daily frequency modes
Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014
Response of OH airglow emissions to mesospheric gravity waves and comparisons with full-wave model simulation at a low-latitude Indian station
First continuous ground-based observations of long period oscillations in the vertically resolved wind field of the stratosphere and mesosphere
Semi-annual oscillation (SAO) of the nighttime ionospheric D region as detected through ground-based VLF receivers
Meteor radar quasi 2-day wave observations over 10 years at Collm (51.3° N, 13.0° E)
Observations of planetary waves in the mesosphere-lower thermosphere during stratospheric warming events
Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique
The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012
Quantification of waves in lidar observations of noctilucent clouds at scales from seconds to minutes
Qinzeng Li, Jiyao Xu, Aditya Riadi Gusman, Hanli Liu, Wei Yuan, Weijun Liu, Yajun Zhu, and Xiao Liu
Atmos. Chem. Phys., 24, 8343–8361, https://doi.org/10.5194/acp-24-8343-2024, https://doi.org/10.5194/acp-24-8343-2024, 2024
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The 2022 Hunga Tonga–Hunga Ha’apai (HTHH) volcanic eruption not only triggered broad-spectrum atmospheric waves but also generated unusual tsunamis which can generate atmospheric gravity waves (AGWs). Multiple strong atmospheric waves were observed in the far-field area of the 2022 HTHH volcano eruption in the upper atmosphere by a ground-based airglow imager network. AGWs caused by tsunamis can propagate to the mesopause region; there is a good match between atmospheric waves and tsunamis.
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.
Gunter Stober, Sharon L. Vadas, Erich Becker, Alan Liu, Alexander Kozlovsky, Diego Janches, Zishun Qiao, Witali Krochin, Guochun Shi, Wen Yi, Jie Zeng, Peter Brown, Denis Vida, Neil Hindley, Christoph Jacobi, Damian Murphy, Ricardo Buriti, Vania Andrioli, Paulo Batista, John Marino, Scott Palo, Denise Thorsen, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Kathrin Baumgarten, Johan Kero, Evgenia Belova, Nicholas Mitchell, Tracy Moffat-Griffin, and Na Li
Atmos. Chem. Phys., 24, 4851–4873, https://doi.org/10.5194/acp-24-4851-2024, https://doi.org/10.5194/acp-24-4851-2024, 2024
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On 15 January 2022, the Hunga Tonga-Hunga Ha‘apai volcano exploded in a vigorous eruption, causing many atmospheric phenomena reaching from the surface up to space. In this study, we investigate how the mesospheric winds were affected by the volcanogenic gravity waves and estimated their propagation direction and speed. The interplay between model and observations permits us to gain new insights into the vertical coupling through atmospheric gravity waves.
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.
Jan Laštovička
Atmos. Chem. Phys., 23, 5783–5800, https://doi.org/10.5194/acp-23-5783-2023, https://doi.org/10.5194/acp-23-5783-2023, 2023
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Increasing concentration of greenhouse gases, particularly of CO2, in the atmosphere causes well-known heating of the troposphere and surface. However, the increasing concentration of CO2 also affects higher levels of the atmosphere, the stratosphere, mesosphere, thermosphere, and ionosphere, where it results in remarkable long-term trends. This article reviews significant progress in investigations of long-term trends in the mesosphere, thermosphere, and ionosphere during the period 2018–2022.
Cornelius Csar Jude H. Salinas, Dong L. Wu, Jae N. Lee, Loren C. Chang, Liying Qian, and Hanli Liu
Atmos. Chem. Phys., 23, 1705–1730, https://doi.org/10.5194/acp-23-1705-2023, https://doi.org/10.5194/acp-23-1705-2023, 2023
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Upper mesospheric carbon monoxide's (CO) photochemical lifetime is longer than dynamical timescales. This work uses satellite observations and model simulations to establish that the migrating diurnal tide and its seasonal and interannual variabilities drive CO primarily through vertical advection. Vertical advection is a transport process that is currently difficult to observe. This work thus shows that we can use CO as a tracer for vertical advection across seasonal and interannual timescales.
Sabine Wüst, Michael Bittner, Patrick J. Espy, W. John R. French, and Frank J. Mulligan
Atmos. Chem. Phys., 23, 1599–1618, https://doi.org/10.5194/acp-23-1599-2023, https://doi.org/10.5194/acp-23-1599-2023, 2023
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Ground-based OH* airglow measurements have been carried out for almost 100 years. Advanced detector technology has greatly simplified the automatic operation of OH* airglow observing instruments and significantly improved the temporal and/or spatial resolution. Studies based on long-term measurements or including a network of instruments are reviewed, especially in the context of deriving gravity wave properties. Scientific and technical challenges for the next few years are described.
Natalie Kaifler, Bernd Kaifler, Markus Rapp, and David C. Fritts
Atmos. Chem. Phys., 23, 949–961, https://doi.org/10.5194/acp-23-949-2023, https://doi.org/10.5194/acp-23-949-2023, 2023
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We used a lidar to measure polar mesospheric clouds from a balloon floating in the upper stratosphere. The thin-layered ice clouds at 83 km altitude are perturbed by waves. The high-resolution lidar soundings reveal small-scale structures induced by the breaking of those waves. We study these patterns and find that they occur very often. We show their morphology and discuss associated dynamical physical processes, which help to interpret case studies and to guide modelling.
Prosper K. Nyassor, Cristiano M. Wrasse, Igo Paulino, Eliah F. M. T. São Sabbas, José V. Bageston, Kleber P. Naccarato, Delano Gobbi, Cosme A. O. B. Figueiredo, Toyese T. Ayorinde, Hisao Takahashi, and Diego Barros
Atmos. Chem. Phys., 22, 15153–15177, https://doi.org/10.5194/acp-22-15153-2022, https://doi.org/10.5194/acp-22-15153-2022, 2022
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This work investigates the sources of concentric gravity waves (CGWs) excited by a moving system of clouds with several overshooting regions on 1–2 October 2019 at São Martinho da Serra. The parameters of these waves were estimated using 2D spectral analysis and their source locations identified using backward ray tracing. Furthermore, the sources of these waves were properly identified by tracking the individual overshooting regions in space and time since the system of clouds was moving.
Qinzeng Li, Jiyao Xu, Hanli Liu, Xiao Liu, and Wei Yuan
Atmos. Chem. Phys., 22, 12077–12091, https://doi.org/10.5194/acp-22-12077-2022, https://doi.org/10.5194/acp-22-12077-2022, 2022
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We use ground-based airglow network observations, reanalysis data, and satellite observations to explore the propagation process of concentric gravity waves (CGWs) excited by a typhoon between the troposphere, stratosphere, mesosphere, and thermosphere. We find that CGWs in the mesosphere are generated directly by the typhoon but the CGW observed in the thermosphere may be excited by CGW dissipation in the mesosphere, rather than directly excited by a typhoon and propagated to the thermosphere.
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.
Manfred Ern, Mohamadou Diallo, Peter Preusse, Martin G. Mlynczak, Michael J. Schwartz, Qian Wu, and Martin Riese
Atmos. Chem. Phys., 21, 13763–13795, https://doi.org/10.5194/acp-21-13763-2021, https://doi.org/10.5194/acp-21-13763-2021, 2021
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Details of the driving of the semiannual oscillation (SAO) of the tropical winds in the middle atmosphere are still not known. We investigate the SAO and its driving by small-scale gravity waves (GWs) using satellite data and different reanalyses. In a large altitude range, GWs mainly drive the SAO westerlies, but in the upper mesosphere GWs seem to drive both SAO easterlies and westerlies. Reanalyses reproduce some features of the SAO but are limited by model-inherent damping at upper levels.
Fabio Vargas, Jorge L. Chau, Harikrishnan Charuvil Asokan, and Michael Gerding
Atmos. Chem. Phys., 21, 13631–13654, https://doi.org/10.5194/acp-21-13631-2021, https://doi.org/10.5194/acp-21-13631-2021, 2021
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We study large- and small-scale gravity wave cases observed in both airglow imagery and meteor radar data obtained during the SIMONe campaign carried out in early November 2018. We calculate the intrinsic features of several waves and estimate their impact in the mesosphere and lower thermosphere region via transferring energy and momentum to the atmosphere. We also associate cases of large-scale waves with secondary wave generation in the stratosphere.
Bingkun Yu, Xianghui Xue, Christopher J. Scott, Jianfei Wu, Xinan Yue, Wuhu Feng, Yutian Chi, Daniel R. Marsh, Hanli Liu, Xiankang Dou, and John M. C. Plane
Atmos. Chem. Phys., 21, 4219–4230, https://doi.org/10.5194/acp-21-4219-2021, https://doi.org/10.5194/acp-21-4219-2021, 2021
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A long-standing mystery of metal ions within Es layers in the Earth's upper atmosphere is the marked seasonal dependence, with a summer maximum and a winter minimum. We report a large-scale winter-to-summer transport of metal ions from 6-year multi-satellite observations and worldwide ground-based stations. A global atmospheric circulation is responsible for the phenomenon. Our results emphasise the effect of this atmospheric circulation on the transport of composition in the upper atmosphere.
Viswanathan Lakshmi Narayanan, Satonori Nozawa, Shin-Ichiro Oyama, Ingrid Mann, Kazuo Shiokawa, Yuichi Otsuka, Norihito Saito, Satoshi Wada, Takuya D. Kawahara, and Toru Takahashi
Atmos. Chem. Phys., 21, 2343–2361, https://doi.org/10.5194/acp-21-2343-2021, https://doi.org/10.5194/acp-21-2343-2021, 2021
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In the past, additional sodium peaks occurring above the main sodium layer of the upper mesosphere were discussed. Here, formation of an additional sodium peak below the main sodium layer peak is discussed in detail. The event coincided with passage of multiple mesospheric bores, which are step-like disturbances occurring in the upper mesosphere. Hence, this work highlights the importance of such mesospheric bores in causing significant changes to the minor species concentration in a short time.
Xiao Liu, Jiyao Xu, Jia Yue, and Hanli Liu
Atmos. Chem. Phys., 20, 14437–14456, https://doi.org/10.5194/acp-20-14437-2020, https://doi.org/10.5194/acp-20-14437-2020, 2020
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Large wind shears in the mesosphere and lower thermosphere are recognized as a common phenomenon. Simulation and ground-based observations show that the main contributor of large wind shears is gravity waves. We present a method of deriving wind shears induced by gravity waves according to the linear theory and using the global temperature observations by SABER (Sounding of the Atmosphere using Broadband Emission Radiometry). Our results agree well with observations and model simulations.
Gunter Stober, Kathrin Baumgarten, John P. McCormack, Peter Brown, and Jerry Czarnecki
Atmos. Chem. Phys., 20, 11979–12010, https://doi.org/10.5194/acp-20-11979-2020, https://doi.org/10.5194/acp-20-11979-2020, 2020
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This paper presents a first cross-comparison of meteor ground-based observations and a meteorological analysis (NAVGEM-HA) to compare a seasonal climatology of winds and temperatures at the mesosphere/lower thermosphere. The validation is insofar unique as we not only compare the mean state but also provide a detailed comparison of the short time variability of atmospheric tidal waves. Our analysis questions previous results claiming the importance of lunar tides.
W. John R. French, Andrew R. Klekociuk, and Frank J. Mulligan
Atmos. Chem. Phys., 20, 8691–8708, https://doi.org/10.5194/acp-20-8691-2020, https://doi.org/10.5194/acp-20-8691-2020, 2020
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We explore a quasi-quadrennial oscillation (QQO; 3–4 K amplitude, ~ 4-year period) in mesopause region temperatures observed in 24 years of hydroxyl airglow measurements over Davis, Antarctica (68° S, 78° E). Correlation and composite analysis using meteorological reanalysis and satellite data reveals complex patterns on the QQO timescale in both hemispheres. Modulation of the meridional circulation, linked to the propagation of gravity waves, plays a significant role in producing the QQO response.
Jörg Gumbel, Linda Megner, Ole Martin Christensen, Nickolay Ivchenko, Donal P. Murtagh, Seunghyuk Chang, Joachim Dillner, Terese Ekebrand, Gabriel Giono, Arvid Hammar, Jonas Hedin, Bodil Karlsson, Mikael Krus, Anqi Li, Steven McCallion, Georgi Olentšenko, Soojong Pak, Woojin Park, Jordan Rouse, Jacek Stegman, and Georg Witt
Atmos. Chem. Phys., 20, 431–455, https://doi.org/10.5194/acp-20-431-2020, https://doi.org/10.5194/acp-20-431-2020, 2020
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Gravity waves can link together atmospheric conditions over large distances. MATS is a new Swedish satellite that will study gravity waves at altitudes around 80–110 km. MATS will take images of emissions from excited molecules, so-called airglow, and of the highest clouds in our atmosphere, so-called noctilucent clouds. These measurements will be analysed to provide three-dimensional wave structures and a comprehensive picture of wave interactions in the atmosphere.
Yuke Wang, Valerii Shulga, Gennadi Milinevsky, Aleksey Patoka, Oleksandr Evtushevsky, Andrew Klekociuk, Wei Han, Asen Grytsai, Dmitry Shulga, Valery Myshenko, and Oleksandr Antyufeyev
Atmos. Chem. Phys., 19, 10303–10317, https://doi.org/10.5194/acp-19-10303-2019, https://doi.org/10.5194/acp-19-10303-2019, 2019
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The major sudden stratospheric warming (SSW) dramatically changed atmospheric conditions. This event is accompanied by a sharp increase in the polar stratosphere temperature, zonal wind reverse, and strong changes in the polar mesosphere. These changes affect even the midlatitude mesosphere, which is not widely covered by observations. Our newly installed microwave radiometer allowed for studying mesospheric zonal wind and CO variations to understand the SSW 2018 effects at midlatitudes.
Wen Yi, Xianghui Xue, Iain M. Reid, Damian J. Murphy, Chris M. Hall, Masaki Tsutsumi, Baiqi Ning, Guozhu Li, Robert A. Vincent, Jinsong Chen, Jianfei Wu, Tingdi Chen, and Xiankang Dou
Atmos. Chem. Phys., 19, 7567–7581, https://doi.org/10.5194/acp-19-7567-2019, https://doi.org/10.5194/acp-19-7567-2019, 2019
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The seasonal variations in the mesopause densities, especially with regard to its global structure, are still unclear. In this study, we report the climatology of the mesopause density estimated using multiyear observations from nine meteor radars from Arctic to Antarctic latitudes. The results reveal a significant AO and SAO in mesopause density, an asymmetry between the two polar regions and evidence of intraseasonal oscillations (ISOs), perhaps associated with the ISOs of the troposphere.
Sabine Wüst, Carsten Schmidt, Patrick Hannawald, Michael Bittner, Martin G. Mlynczak, and James M. Russell III
Atmos. Chem. Phys., 19, 6401–6418, https://doi.org/10.5194/acp-19-6401-2019, https://doi.org/10.5194/acp-19-6401-2019, 2019
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In winter 2016, the camera system FAIM derived information about the OH* airglow at ca. 86 km height during six flights on board the research aircraft FALCON in northern Scandinavia. Coincident ground- and satellite-based measurements (GRIPS and TIMED-SABER) complete the data set. The data are analysed with respect to the temporal and spatial evolution of small-scale atmospheric dynamics just before a minor stratospheric warming. Special emphasis is placed on possible instability features.
Maosheng He and Jorge Luis Chau
Atmos. Chem. Phys., 19, 5993–6006, https://doi.org/10.5194/acp-19-5993-2019, https://doi.org/10.5194/acp-19-5993-2019, 2019
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We propose an approach to resolve waves with multiple spatial scales at a given frequency using ground-based detectors from few longitudinal sectors. The approach is used to investigate near-12 h waves. Results suggest that broadly reported enhancements of two solar nonmigrating tides during sudden stratospheric warming events are just low-frequency-resolved signatures of two neighboring waves. The tides do not enhance.
Dimitry Pokhotelov, Gunter Stober, and Jorge Luis Chau
Atmos. Chem. Phys., 19, 5251–5258, https://doi.org/10.5194/acp-19-5251-2019, https://doi.org/10.5194/acp-19-5251-2019, 2019
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Twelve years of radar observations from a mid-latitude location in Kühlungsborn, Germany have been analysed to study characteristics of mesospheric summer echoes (MSEs). The statistical analysis shows that MSEs have a strong daytime preference and early summer seasonal preference. It is demonstrated that the meridional wind transport from polar regions is the important controlling factor for MSEs, while no clear connection to geomagnetic and solar activity is found.
Nikoloz Gudadze, Gunter Stober, and Jorge L. Chau
Atmos. Chem. Phys., 19, 4485–4497, https://doi.org/10.5194/acp-19-4485-2019, https://doi.org/10.5194/acp-19-4485-2019, 2019
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We show a possibility of measuring mean vertical winds during the summer months using polar mesosphere summer echo (PMSE) observations. Middle Atmosphere Alomar Radar System observations of PMSE five-beam radial velocities are analysed to obtain the results. We found that sampling issues are the reason for bias in vertical wind measurements at the edges of PMSE altitudes. However, the PMSE is a good tracer for the mean vertical wind estimation at the central altitudes with its peak occurrence.
Bingkun Yu, Xianghui Xue, Xin'an Yue, Chengyun Yang, Chao Yu, Xiankang Dou, Baiqi Ning, and Lianhuan Hu
Atmos. Chem. Phys., 19, 4139–4151, https://doi.org/10.5194/acp-19-4139-2019, https://doi.org/10.5194/acp-19-4139-2019, 2019
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It reports the long-term climatology of the intensity of Es layers from COSMIC satellites. The global Es maps present high-resolution spatial distributions and seasonal dependence. It mainly occurs at mid-latitudes and polar regions. Based on wind shear theory, simulation results indicate the convergence of vertical ion velocity could partially explain the Es seasonal dependence and some disagreements between observations and simulations suggest other processes play roles in the Es variations.
Xianchang Yue, Jonathan S. Friedman, Qihou Zhou, Xiongbin Wu, and Jens Lautenbach
Atmos. Chem. Phys., 19, 3207–3221, https://doi.org/10.5194/acp-19-3207-2019, https://doi.org/10.5194/acp-19-3207-2019, 2019
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Using 11 years of lidar temperature data, the seasonal variations (SVs) of gravity waves (GWs) are addressed in the tropical mesopause region, shown to be clearly associated with the SVs of zonal winds reported in the literature. The SVs of GWs are determined by the filtering effect of the local background wind. The altitudes of GW potential energy have a close relation to the upper mesospheric temperature inversion layers (TILs), which provides support for the formation mechanism of TILs.
Robert Menke, Nikola Vasiljević, Jakob Mann, and Julie K. Lundquist
Atmos. Chem. Phys., 19, 2713–2723, https://doi.org/10.5194/acp-19-2713-2019, https://doi.org/10.5194/acp-19-2713-2019, 2019
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This research utilizes several months of lidar measurements from the Perdigão 2017 campaign to investigate flow recirculation zones that occur at the two parallel ridges at the measurement site in Portugal. We found that recirculation occurs in over 50 % of the time when the wind direction is perpendicular to the direction of the ridges. Moreover, we show three-dimensional changes of the zones along the ridges and the implications of recirculation on wind turbines that are operating downstream.
Christian von Savigny, Dieter H. W. Peters, and Günter Entzian
Atmos. Chem. Phys., 19, 2079–2093, https://doi.org/10.5194/acp-19-2079-2019, https://doi.org/10.5194/acp-19-2079-2019, 2019
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This study investigates solar effects in radio reflection height observations in the ionospheric D region at an altitude of about 80 km at northern midlatitudes. The analyzed time series covers almost six solar cycles. Statistically significant solar 27-day and 11-year signatures are identified. However, the driving mechanisms are not fully understood. We also provide evidence for dynamical effects on the radio reflection heights with periods close to the solar rotational cycle.
Yuta Hozumi, Akinori Saito, Takeshi Sakanoi, Atsushi Yamazaki, and Keisuke Hosokawa
Atmos. Chem. Phys., 18, 16399–16407, https://doi.org/10.5194/acp-18-16399-2018, https://doi.org/10.5194/acp-18-16399-2018, 2018
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Spatial structures of wave disturbances in the upper atmosphere were investigated with space-borne imaging from the International Space Station. The wave disturbance occurred around an altitude of 100 km, and is called a mesospheric bore. The large-scale structure of mesospheric bores has not been fully captured by previous ground-based imagers, but the space-borne imaging captured a bore with a wide field of view, and showed that bores can have a large undulating wave front as long as 2000 km.
Michael Gerding, Jochen Zöllner, Marius Zecha, Kathrin Baumgarten, Josef Höffner, Gunter Stober, and Franz-Josef Lübken
Atmos. Chem. Phys., 18, 15569–15580, https://doi.org/10.5194/acp-18-15569-2018, https://doi.org/10.5194/acp-18-15569-2018, 2018
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We describe the first comparative study of noctilucent clouds (NLCs) and mesospheric summer echoes at midlatitudes. Therefore, this study compares fresh clouds (small particles) with fully evolved clouds in the mesosphere, hinting at their evolution. It is shown that, in contrast to higher latitudes, here only a thin layer of fresh particles exist above the NLCs. This gives evidence that NLCs are not formed locally but are typically advected. This needs to be acknowledged in trend studies.
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.
Tao Li, Chao Ban, Xin Fang, Jing Li, Zhaopeng Wu, Wuhu Feng, John M. C. Plane, Jiangang Xiong, Daniel R. Marsh, Michael J. Mills, and Xiankang Dou
Atmos. Chem. Phys., 18, 11683–11695, https://doi.org/10.5194/acp-18-11683-2018, https://doi.org/10.5194/acp-18-11683-2018, 2018
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A total of 154 nights of observations by the USTC Na temperature and wind lidar (32° N, 117° E) suggest significant seasonal variability in the mesopause. Chemistry plays an important role in Na atom formation. More than half of the observed gravity wave (GW) momentum flux (MF), whose divergence determines the GW forcing, is induced by short-period (10 min–2 h) waves. The anticorrelation between MF and zonal wind (U) suggests strong filtering of short-period GWs by semiannual oscillation U.
Jorge L. Chau, Derek McKay, Juha P. Vierinen, Cesar La Hoz, Thomas Ulich, Markku Lehtinen, and Ralph Latteck
Atmos. Chem. Phys., 18, 9547–9560, https://doi.org/10.5194/acp-18-9547-2018, https://doi.org/10.5194/acp-18-9547-2018, 2018
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Combining a phased-array power radar and a phased-array radio telescope, we have been able to identify and characterized horizontal structures and movement of noctilucent clouds, but at 3 m scales instead of optical scales. As a byproduct of our observations, we have studied their angular dependence. We show a new alternative to study these clouds on routine basis and therefore study the atmospheric dynamics that modulate them.
Gunter Stober, Svenja Sommer, Carsten Schult, Ralph Latteck, and Jorge L. Chau
Atmos. Chem. Phys., 18, 6721–6732, https://doi.org/10.5194/acp-18-6721-2018, https://doi.org/10.5194/acp-18-6721-2018, 2018
Kathrin Baumgarten, Michael Gerding, Gerd Baumgarten, and Franz-Josef Lübken
Atmos. Chem. Phys., 18, 371–384, https://doi.org/10.5194/acp-18-371-2018, https://doi.org/10.5194/acp-18-371-2018, 2018
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Gravity waves (GWs) as well as solar tides are a key driving mechanism for the circulation in the Earth's atmosphere. The temporal variation of these waves is studied using a record long 10-day continuous Rayleigh–Mie–Raman lidar sounding at midlatitudes. This data set shows a large variability of these waves on timescales of a few days and therefore provides new insights into wave intermittency phenomena, which can help to improve model simulations.
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.
Jens Hildebrand, Gerd Baumgarten, Jens Fiedler, and Franz-Josef Lübken
Atmos. Chem. Phys., 17, 13345–13359, https://doi.org/10.5194/acp-17-13345-2017, https://doi.org/10.5194/acp-17-13345-2017, 2017
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We present altitude profiles of winds and temperatures in the Arctic strato- and mesosphere obtained during three Januaries. The data show large year-to-year variations. We compare the observations to model data. For monthly mean profiles we find good agreement below 55 km altitude but also differences of up to 20 K and 20 m s-1 above. The fluctuations during single nights indicate gravity waves. The kinetic energy of such waves is typically 5 to 10 times larger than their potential energy.
Dhvanit Mehta, Andrew J. Gerrard, Yusuke Ebihara, Allan T. Weatherwax, and Louis J. Lanzerotti
Atmos. Chem. Phys., 17, 911–919, https://doi.org/10.5194/acp-17-911-2017, https://doi.org/10.5194/acp-17-911-2017, 2017
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This paper presents an investigation into the sources of atmospheric gravity waves observed at 90 km above Amundsen-Scott South Pole Station, Antarctica. By combining gravity wave characteristics obtained from imager data and a numerical model for 3-D wave propagation through the atmosphere, we find that the development of baroclinic instabilities via displacement of the polar vortex is a significant and unique source of vertically propagating, short-period (< 1 h) gravity waves in the region.
Christoph Kalicinsky, Peter Knieling, Ralf Koppmann, Dirk Offermann, Wolfgang Steinbrecht, and Johannes Wintel
Atmos. Chem. Phys., 16, 15033–15047, https://doi.org/10.5194/acp-16-15033-2016, https://doi.org/10.5194/acp-16-15033-2016, 2016
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The analysis of temperatures in the mesopause region between 1988 to 2015 shows, besides the known correlation with the 11-year solar activity cycle, a trend reversal in 2008 that can be described by a long-term oscillation. Understanding such long periodic oscillations in the atmosphere is of prime importance for climate modelling and predictions of future trends.
Maya García-Comas, Francisco González-Galindo, Bernd Funke, Angela Gardini, Aythami Jurado-Navarro, Manuel López-Puertas, and William E. Ward
Atmos. Chem. Phys., 16, 11019–11041, https://doi.org/10.5194/acp-16-11019-2016, https://doi.org/10.5194/acp-16-11019-2016, 2016
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In this paper, for the first time, temperature longitudinal oscillations are derived from 20 to 150 km from a single instrument. A climatology of amplitudes and phases of zonal waves with odd daily frequencies is presented on a global scale. The interannual variability in amplitudes of the migrating modes shows a QBO in the MLT, which is probably originated in the stratosphere. The results are useful for testing general circulation models considering tidal effects in the MLT region.
Silje Eriksen Holmen, Chris M. Hall, and Masaki Tsutsumi
Atmos. Chem. Phys., 16, 7853–7866, https://doi.org/10.5194/acp-16-7853-2016, https://doi.org/10.5194/acp-16-7853-2016, 2016
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Atmospheric temperatures at 90 km height above Tromsø, Norway, from 2003 to 2014 have been determined using meteor radar. Periodic oscillations ranging from ~ 9 days to a year were found in the dataset, which were related to the large-scale circulation in the middle atmosphere and with wave activity. A trend analysis was performed, revealing an overall weak cooling trend from 2003 to 2014, which is in line with other recent studies on mesopause region (~ 90 km) temperature trends.
Rupesh N. Ghodpage, Michael P. Hickey, Alok K. Taori, Devendraa Siingh, and Parashram T. Patil
Atmos. Chem. Phys., 16, 5611–5621, https://doi.org/10.5194/acp-16-5611-2016, https://doi.org/10.5194/acp-16-5611-2016, 2016
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Gravity-wave-induced oscillations have been characterized over Kolhapur (16.8°N and 74.2°E), India, using the adiabatic variations in OH airglow intensity and temperature data. The results show that there exist large deviations from one investigation to the other. We also use a full-wave model to simulate the response of OH emission to the wave motion and compare the results with observed values. This report discusses the observed wave characteristics and cause of the noted difference.
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.
Israel Silber, Colin Price, and Craig J. Rodger
Atmos. Chem. Phys., 16, 3279–3288, https://doi.org/10.5194/acp-16-3279-2016, https://doi.org/10.5194/acp-16-3279-2016, 2016
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We report for the first time that the semi-annual oscillation (SAO) is one of the dominant oscillations in the nighttime lower ionosphere, using ground-based measurements of VLF signals reflected off the lower part of the ionosphere. We conclude that the origins of this oscillation are oscillatory changes of the D region's electrical characteristics, driven by NOx transport from the lower thermosphere. This oscillation should be considered in lower ionospheric and VLF wave propagation models.
F. Lilienthal and Ch. Jacobi
Atmos. Chem. Phys., 15, 9917–9927, https://doi.org/10.5194/acp-15-9917-2015, https://doi.org/10.5194/acp-15-9917-2015, 2015
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The quasi 2-day wave (QTDW), one of the most striking features in the mesosphere/lower thermosphere, is analyzed using meteor radar measurements at Collm (51°N, 13°E) during 2004-2014. The QTDW has periods lasting between 43 and 52h during strong summer bursts, and weaker enhancements are found during winter. A correlation between QTDW amplitudes and wind shear suggests baroclinic instability to be a likely forcing mechanism.
N. H. Stray, Y. J. Orsolini, P. J. Espy, V. Limpasuvan, and R. E. Hibbins
Atmos. Chem. Phys., 15, 4997–5005, https://doi.org/10.5194/acp-15-4997-2015, https://doi.org/10.5194/acp-15-4997-2015, 2015
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Planetary wave activity measured in the mesosphere to lower thermosphere is shown to increase drastically after strong stratospheric polar cap wind reversals associated with sudden stratospheric warmings. In addition, a moderate but significant correlation was found between planetary wave enhancement in the mesosphere to lower thermosphere and all stratospheric polar cap wind reversals, irrespective of the strength of the reversal.
M. Pramitha, M. Venkat Ratnam, A. Taori, B. V. Krishna Murthy, D. Pallamraju, and S. Vijaya Bhaskar Rao
Atmos. Chem. Phys., 15, 2709–2721, https://doi.org/10.5194/acp-15-2709-2015, https://doi.org/10.5194/acp-15-2709-2015, 2015
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Sources and propagation characteristics of high-frequency gravity waves observed in the mesosphere using airglow emissions from Gadanki and Hyderabad, India, are investigated using reverse ray tracing. Wave amplitudes are also traced back, including both radiative and diffusive damping. Interestingly, large vertical shears in the horizontal wind are noticed near the ray terminal points (at 10-12km altitude) and are thus identified to be the source for generating the observed gravity waves.
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
N. Kaifler, G. Baumgarten, J. Fiedler, and F.-J. Lübken
Atmos. Chem. Phys., 13, 11757–11768, https://doi.org/10.5194/acp-13-11757-2013, https://doi.org/10.5194/acp-13-11757-2013, 2013
Cited articles
Allen, S. J. and Vincent, R. A.: Gravity wave activity in the lower atmosphere: Seasonal and latitudinal variations, J. Geophys. Res., 100, 1327–1350, 1995.
Antonita, T. M., Ramkumar, G., Kumar, K. K., and Deepa, V.: Meteor wind radar observations of gravity wave momentum fluxes and their forcing toward the Mesospheric Semiannual Oscillation, J. Geophys. Res., 113, p. 12, https://doi.org/10.1029/2007JD009089, 2008.
Babu, V. S., Kumar, K. K., John, S. R., Subrahmanyam, K. V., and Ramkumar, G.: Meteor radar observations of short-term variability of quasi 2 day waves and their interaction with tides and planetary waves in the mesosphere–lower thermosphere region over Thumba (8.5° N, 77$ ^\circ$ E), J. Geophys. Res., 116, https://doi.org/10.1029/2010JD015390, 15 pp., 2011.
Baldwin, M. P., Gray, L. J., Dunkerton, T. J., Hamilton, K., Haynes, P. H., Randel, W. J., Holton, J. R., Alexander, M. J., Hirota, I., Horinouchi, T., Jones, D. B. A., Kinnersley, J. S., Marquardt, C., Sato, K., and Takahashi, M.: The quasi-biennial oscillation, Rev. Geophys., 39, 179–229, 2001.
Burrage, M. D., Vincent, R. A., Mayr, H., Skinner, W. R., Arnold, N. F., and Hays, P. B.: Long-term variability in the equatorial middle atmopshere zonal wind, J. Geophys. Res., 101, 12847–12854, 1996.
Delisi, D. and Dunkerton, T.: Equatorial semiannual oscillation in zonally averaged temperature observedby the Nimbus 7 SAMS and LIMS, J. Geophys. Res., 93, 3899– 3904, 1988.
Garcia, R. R. and Sassi, F.: Modulation of the mesospheric semiannual oscillation by the quasibiennail oscillation, Earth Planets Space, 51, 563–569, 1999.
Garcia, R. R., Dunkerton, T. J., Lieberman, R. S., and Vincent, R. A.: Climatology of the semiannual oscillation of the tropical middle atmopshere, J. Geophys. Res., 102, 26019–26032, 1997.
Hitchman, M. H. and Leovy, C. B.: Estimation of the Kelvin wave contribution to the Semiannual Oscillation, J. Atmos. Sci., 45, 1462–1475, 1988.
Hocking, W. K., Fuller, B., and Vandepeer, B.: Real-time determination of meteor-related parameters utilizing modem digital technology, J. Atmos. and Solar- Terr. Phys., 63, 155–160, 2001.
Huang, F. T., Mayr, H. G., Reber, C. A., Russell, J. M., Mlynczak, M., and Mengel, J. G.: Stratospheric and mesospheric temperature variations for the quasi-biennial and semiannual (QBO and SAO) oscillations based on measurements from SABER (TIMED) and MLS (UARS), Ann. Geophys., 24, 2131–2149, https://doi.org/10.5194/angeo-24-2131-2006, 2006.
Huang, F. T., Mayr, H., Reber, C. A., Russell III, J. M., Mlynczak, M. G., and Mengel, J. G.: Ozone quasi-biennial oscillations (QBO), semiannual oscillations (SAO), and correlations with temperature in the mesosphere, lower thermosphere, and stratosphere, based on measurements from SABER on TIMED and MLS on UARS, J. Geophys. Res., 113, 15 pp., https://doi.org/10.1029/2007JA012634, 2008.
Kumar, K. K., Swain, D., John, S. R., and Ramkumar, G.: Simultaneous observations of SAO and QBO in winds, temperature and ozone in the tropical middle atmosphere over Thumba (8.5° N, 77° E), Clim. Dynam., 37, 1961–1973, 2011.
Li, T., Liu, A. Z., Lu, X., Li, Z., Franke, S. J., Swenson, G. R., and Dou, X.: Meteor-radar observed mesospheric semi-annual oscillation (SAO) and quasi-biennial oscillation (QBO) over Maui, Hawaii, J. Geophys. Res., 117, https://doi.org/10.1029/2011JD016123, 9 pp., 2012.
Mitchell, N. J., Pancheva, D., Middleton, H. R., and Hagan, M. E.: Mean winds and tides in the Artic mesosphere and lower thermosphere, J. Geophys. Res.-Space Phys., 107, 14 pp., 2002.
Peña-Ortiz, C., Schmidt, H., Giorgetta, M. A., and Keller, M.: QBO modulation of the semiannual oscillation in MAECHAM5 and HAMMONIA, J. Geophys. Res., 115, 19 pp., https://doi.org/10.1029/2010JD013898, 2010.
Ratnam, M. V., Kumar, G. K., Murthy, B. V. K., Patra, A. K., Rao, V. V. M. J., Rao, S. V. B., Kumar, K. K., and Ramkumar, G.: Long-term variability of the low latitude mesospheric SAO and QBO and their relation with stratospheric QBO, Geophys. Res. Lett., 35, 5 pp., https://doi.org/10.1029/2008GL035390, 2008.
Scargle, J. D.: Studies in astronomical time series analysis. III. Fourier transforms, autocorrelation and cross-correlation functions of unevenly spaced data, Astrophys. J., 343, 874–887, 1989.
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