List of all abstracts

Speaker:
Abrahamsen Malin

Alomar




Speaker:
Assink Jelle

KNMI




Speaker:
Belova Evgenia

Swedish Institute of Space Physics


NO TALK

Authors: no talk
no talk



Speaker:
Blanc Elisabeth

CEA




Speaker:
Blixt Mårten

NORSAR AS


THE INFRASONIC SIGNATURE OF POLAR LOW PRESSURE SYSTEMS

Authors: Sven Peter Näsholm (NORSAR); Jelle Assink (KNMI); Chantal Claud (CNRS/LMD); Pieter Smets (KNMI); Maxence Rojo (CNRS/LMD); Kathy Pol (CEA); Steven J. Gibbons (NORSAR); Mårten Blixt (NORSAR)
We consider a set of polar low pressure systems in the North Atlantic and their signature in data recorded at Scandinavian infrasound arrays. The times and coordinates of the polar low events were listed by Senior Forecaster Gunnar Noer at the Norwegian Meteorological Institute based on visual inspection of AVHRR images. Also synoptic observations, METAR (airport observations), in situ soundings, and scatterometer winds were used when compiling the event list. For each of the analyzed events and for each of the infrasound stations, a time-series of direction of arrival (backazimuth) of the dominating infrasound plane wave was estimated from the infrasound array data recordings. These bearings were then compared with the bearings between the infrasound stations and the listed event locations. Based on the comparisons for each polar low event, we assess whether a signature was seen (or not seen) in the infrasound array network data.



Speaker:
Borchevkina Olga

Immanuil Kant Baltic Federal University


STUDY OF THE METEOROLOGICAL PROCESSES INFLUENCE ON THE UPPER ATMOSPHERE AND IONOSPHERE: SIMULATION AND EXPERIMENT

Authors: Olga Borchevkina Immanuel Kant Baltic Federal University Ivan Karpov Immanuel Kant Baltic Federal University, WD IZMIRAN Pavel Vasiliev Immanuel Kant Baltic Federal University Fedor Bessarab Immanuel Kant Baltic Federal University, WD IZMIRAN Alexandra Ilminskaya Immanuel Kant Baltic Federal University
Structure and dynamics of the upper atmosphere, mainly caused by extraterrestrial sources, including the sun. Nevertheless, the impact coming from below also provides a significant contribution to the variability of the upper atmosphere. One of the widely discussed phenomena - meteorological activities in the troposphere. Meteorological processes in the troposphere are a source of strong internal waves wide spectral period, which carry energy and momentum up through the atmosphere. Analysis of the experimental data from observations of the total electron content and pressure shows that the meteorological storm influence on the ionospheric parameters. It was found that the effects of meteorology appear in the ionosphere in the form of local areas of reducing the electron density. Statistical methods of analysis of the dynamics of the ionosphere indicated that ionospheric disturbances are not the random processes. Results of the analysis of ionospheric observations have shown that during periods of meteorological disturbances decrease in the amplitude of the diurnal variations TEC, reaching about 50% in relation to meteorological calm days. The variations in the critical frequency of the F-region of the ionosphere observed decrease in the amplitude of the diurnal variations in the ~ 15%, and the emergence periods manifestations F - scattering. The observation of TEC variation in meteorological activity also reveals increasing variations of parameters of the ionosphere with periods of 2-20 minutes. Analysis ionospheric data suggests that the disturbance identified by ionospheric conditions determined by the local meteorological conditions. Numerical experiment was made to test the hypothesis using global self-consistent model of the thermosphere, ionosphere and protonosphere (GSM TIP). As thermospheric source of disturbance was defined spatially localized moving heat source, simulating the effect of AGW dissipation, connected with meteorological storm. The calculation results demonstrate the dynamics of perturbations of the upper atmosphere and ionosphere parameters caused by the source model. The physical processes that determine the resulting ionospheric disturbances are discussed.



Speaker:
Campus Paola

Department of Earth Sciences, University of Florence, Italy




Speaker:
Charlton-Perez Andrew

University of Reading




Speaker:
Chum Jaroslav

Institute of Atmospheric Physics CAS, Prague


ACOUSTIC GRAVITY WAVES AND OTHER PERTURBATIONS IN THE THERMOSPHERE AND IONOSPHERE BY CONTINUOUS DOPPLER SOUNDING

Authors: J. Chum(1), J. Laštovička(1), T. Šindelářová(1), J. Fišer(1), Z. Mošna(1), M.A. Cabrera(2), J.-Y. Liu(3), (1) Institute of Atmospheric Physics, Bocni II/1401, 14131 Prague 4, Czech Republic (2) Laboratorio de Telecomunicaciones, Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Argentina (3) Institute of Space Science, National Central University, Chung-Li 320, Taiwan Corresponding author: Jaroslav Chum, jachu@ufa.cas.cz
Results of recent observations of ionospheric perturbations on short time scales obtained by international network (Czech Republic, Argentina, Taiwan and South Africa) of multipoint continuous Doppler sounders with time resolution about 10 s are presented. Examples of observation and analysis of propagation of gravity waves (GWs), equatorial spread F (ESF), infrasound from earthquake and large convective systems, as well as ionospheric perturbations caused by solar flares will be shown. Main focus will be on GWs and infrasound. It is documented that roughly poleward propagation of GWs dominates in the local summer, whereas mainly equatorward propagation is observed in the local winter. The observations of co-seismic perturbations by Doppler sounders in the vicinity of ionosondes and seismic sensors proved that the co-seismic perturbations are caused by approximately vertically propagating infrasound waves triggered by vertical motion of the ground surface. Numerical simulations and Doppler measurements confirmed that in the vicinity from epicenters of strong earthquake, the infrasound propagates in nonlinear regime in the upper atmosphere, which resulted in the change of spectral content of the wave packet (shift toward lower frequencies) and formation of N-shaped pulse that resembled a shock wave. Infrasound waves with periods from about 0.0035 to 0.022 Hz associated with large convective systems and typhoons that passed over Taiwan were observed in the ionosphere; usually the frequency of around 0.005 Hz was recorded.



Speaker:
Czanik Csenge

Hungarian Academy of Sciences




Speaker:
Escudier Marc

Enviroearth


STUDY OF THE RESPONSE OF AN INFRASOUND STATION: MB3 AND WIND NOISE REDUCTION SYSTEMS

Authors: Marc Escudier (Enviroearth), Nathalie Olivier (SeismoWave)
SeismoWave and Enviroearth, manufacturers, installers and operators of infrasound stations all over the world, have come together to improve the instrumentation on infrasound measuring stations. The MB3d microbarometer is a new sensor that embeds a digitizer with remote calibration capabilities. With 1 Gb miniseed data storage, and less than 1W consumption, this sensor is an effective solution for temporary applications. The Wind Noise Reduction System (also known as WNRS) are air inlets that allow to filtrate noise of the wind and the surrounding environment, improving the signal over noise ratio. New designs were made recently and the power spectral density graphs of two systems will be shown. At a frequency close to 1Hz, these filters can reduce up to 20dB the impact of the surrounding noise, although the attenuation depends on the kind of filter and the frequency. We are also in the process of designing and developing an all-inclusive portable infrasound station and would like to discuss with the participants our first findings.



Speaker:
Espy Patrick

Norwegian University of Science and Technology, Trondheim




Speaker:
frobert laurent

EMSC




Speaker:
Gausa Michael

Andoya Space Center




Speaker:
Ghica Daniela

National Institute for Earth Physics


NEW INFRASOUND STATIONS DEPLOYED IN ROMANIA – ENHANCED CONTRIBUTION TO ARISE DESIGN STUDY PROJECT

Authors: Daniela Ghica (National Data Centre, National Institute for Earth Physics), Constantin Ionescu (National Institute for Earth Physics) and Mihaela Popa (National Data Centre, National Institute for Earth Physics)
During the second half of 2016, the infrasound monitoring network in Romania was developed by deployment of two new stations, in addition to IPLOR, the 6-element acoustic array installed at Plostina by National Institute for Earth Physics (NIEP). The first station, BURARI infrasound research array, consists of four elements installed in late July 2016 in the northern part of Romania, in Bucovina region, under a joint effort of Air Force Technical Application Center AFTAC (USA) and NIEP. BURARI elements, sited in vicinity of the central elements of BURAR seismic array (1.2 km aperture) are equipped with Chaparral Physics Model 21 microbarometers and Reftek RT 130 data loggers. The data are used primarily for research purposes within the scientific collaboration project between NIEP and AFTAC, but they could be also provided to the infrasound experts interested, i.e. ARISE community. The second new infrasound array is a PTS portable four-element array (I67RO), which has been deployed in the end of September 2016, for one year, within a collaboration project between NIEP and the Provisional Technical Secretariat of the Preparatory Commission for the CTBTO. This array, located in the western part of Romania, at Marisel (Cluj County), covers a 0.9 km aperture and is equipped with CEA/DAM MB2005 microbarometers and Reftek RT 130 data loggers. As mentioned in the collaboration letter signed by the International Data Centre (IDC) director, this NIEP-PTS joint experiment aims to contribute both to advanced understanding of infrasound sources in Central-Europe and to ARISE design study project, as an expansion of the spatial coverage of the European infrasound network. We present the results of processing of the data recorded by the new infrasound arrays deployed in Romania. CEA/DASE PMCC algorithm embedded in DTK-GPMCC (extended CTBTO NDC-in-a-box) was applied to obtain the detection arrival bulletins for each station. DTK-DIVA software (extended CTBTO NDC-in-a-box) was used to plot and analyze the results, in order to assess station detectability and the capacity of fusing detections into support of infrasound monitoring activity at NIEP.



Speaker:
Gibbons Steven J.

NORSAR


TEMPORAL VARIABILITY OF INFRASOUND PROPAGATION AND DETECTABILITY IN THE EUROPEAN ARCTIC

Authors: SJ Gibbons (NORSAR), SP Näsholm (NORSAR), T Kvaerna (NORSAR), M Blixt (NORSAR)
The European Arctic makes an excellent laboratory for the study of infrasound propagation given numerous infrasound arrays and many repeating sources of infrasound. We have compiled an extensive database of repeating, seismically constrained, Ground Truth explosions including many thousands of events and spanning almost 30 years. For each explosion, we include parametric descriptions of the infrasonic wavetrain observed at each available station. Non-detection is also a key observation for an event-station combination. Paths cover distance ranges from a few tens of kilometers to many hundreds of kilometers, an exceptional range of azimuthal directions, and observations exist for all times of year. We display and discuss changes in infrasound propagation for tropospheric, stratospheric and thermospheric phases over time-scales from days to seasons and from year-to-year.



Speaker:
Hagen Jonas

Institute for Applied Physics (IAP), University of Bern


STRATOSPHERIC AND MESOSPHERIC WIND MEASUREMENTS FROM THE NEW WIRA-C WIND RADIOMETER AND COMPARISON TO THE DOPPLER LIDAR ON LA RéUNION ISLAND

Authors: Jonas Hagen, Niklaus Kämpfer; Institute of Applied Physics, University of Bern, Bern, Switzerland. Sergey Khaykin, Alain Hauchecorne; LATMOS-IPSL, Université Versailles St.-Quenitn, CNRS/INSU, Guyancourt, France
Measurements of wind speeds in altitudes between 30 and 70 km are surprisingly rare. Passive microwave radiometry and Doppler lidar techniques provide two methods for covering this gap region. With the Rayleigh-Mie Doppler wind lidar of CNRS/INSU (Guyancourt, France) and OSUR (La Réunion, France) and the passive microwave radiometer WIRA-C of the IAP (Bern, Switzerland) two such instruments are collocated in the Maïdo observatory on the tropical island La Réunion (21° South, France). Both instruments participate in the ARISE2 project that is funded by the European Commission Horizon 2020. The Rayleigh-Mie Doppler wind lidar is an active sounder, measuring the Doppler shift of backscattered visible light and can provide wind profiles from 5 up to 50 km with a vertical resolution of up to 100 m and an accuracy better than 1 m/s up to 30 km. On the other side, WIRA-C is a passive microwave radiometer that measures the Doppler shift of the ozone thermal emission line at 142 GHz. The radiometer has a high spectral resolution of 12.2 kHz and a band width of 200 MHz and can thus exploit the pressure broadening of the ozone line to retrieve an altitude resolved wind profile. The retrieval is based on a model of the atmosphere and optimal estimation techniques implemented by ARTS and Atmlab/Qpack, but in contrast to previous versions the atmospheric model is three-dimensional. Meaningful wind speeds can be retrieved for an altitude range of 30 to 70 km with a vertical resolution of up to 4 km. WIRA-C is able to measure continuously, independent of daylight and clouds. WIRA-C has been installed on the Maïdo observatory in August 2016 and has measured since then whenever the optical thickness of the atmosphere was low enough. The Doppler lidar at Maïdo was operated on a campaign basis since 2013 and routinely twice a week since September 2015. We present the WIRA-C instrument and its measurement results for the tropical summer 2016/17 and compare them to coincident measurements of the Rayleigh-Mie Doppler wind lidar. Further, we compare the measurements to ECMWF model data and, on the lower domain around 30 km altitude, to balloon soundings.



Speaker:
Hauchecorne Alain

LATMOS-CNRS




Speaker:
Hibbins Robert

NTNU


SEMIDIURNAL TIDAL VARIABILITY DERIVED FROM A LONGITUDINAL CHAIN OF NORTHERN HEMISPHERE SUPERDARN RADARS

Authors: R.E. Hibbins, P.J. Espy. NTNU, Trondheim, Norway.
Hourly mean meteor wind data from a longitudinal chain of eight mid-latitude northern hemisphere SuperDARN radars have been used to extract the spatial (migrating and non-migrating) components of the semidiurnal tide in the lower thermosphere meridional wind between 1995 and 2016. Unlike in the southern hemisphere, the semidiurnal tide is dominated by the migrating (W2) component, though small but significant W1 and W3 contributions to the semidiurnal tide are measured, especially around the equinoxes. Data analysis and validation will be presented,together with initial results on the inter-annual variability of the different tidal components and their response to sudden stratospheric warmings.



Speaker:
Hildebrand Jens

Leibniz-Institute of Atmospheric Physics


TEMPERATURE OBSERVATIONS ABOVE ALOMAR – SEASONAL CYCLE AND GRAVITY WAVES – AN UPDATE

Authors: Jens Hildebrand, Gerd Baumgarten, Jens Fiedler, Franz-Josef Lübken (Leibniz-Institute of Atmospheric Physics (IAP), Kühlungsborn, Germany)
The ALOMAR Rayleigh/Mie/Raman lidar at Andøya in Northern Norway measures temperatures on a routine basis since 1997. Due to its full daylight capability, observations cover all seasons and all local times. Previous studies already derived a seasonal cycle of middle-atmosphere temperatures above ALOMAR, basing on day-mean temperature profiles. Since then the amount of data tripled (now about 15 000 h) and the signal quality of the lidar improved remarkably, extending its altitude coverage and allowing higher temporal and vertical resolutions on the order of few minutes and few hundred meters, respectively. Therefore, it is reasonable to update and extent these studies with regard to various aspects, e.g., tides, gravity waves, and year-to-year variations. We have implemented new automated methods for retrieval, data reduction, and processing, respecting data standards developed within the ARISE2 project. We will present first results concerning the seasonal cycle of temperatures above ALOMAR and gravity wave studies during winter and summer.



Speaker:
Hupe Patrick

BGR, Hannover, Germany


NO TALK

Authors: no talk
no talk



Speaker:
HUSSON Philippe

Meteo-France (VAAC Toulouse)




Speaker:
Keckhut Philippe

LATMOS/UVSQ


RECENT STRATOSPHERIC TEMPERATURE TRENDS USING AMSU AND GPS RADIO OCCULTATIONS OBSERVATIONS

Authors: P. Keckhut(LATMOS, UVSQ, Guyancourt France), S.M. Khaykin (LATMOS, UVSQ, Guyancourt France), B. Funatsu (LETG-Rennes-COSTEL,CNRS, Rennes France), C. Claud (LMD,CNRS, Palaiseau France), A. Hauchecorne (LATMOS, CNRS, Guyancourt France)
A variety of observations and model simulations indicate that the stratosphere has cooled in most of the layers since 1979. Different analyses of the SSU series reveal large differences due to the complex challenge of combining successive experiments and trends seems to disappear from 1995 to 2015. Evaluation of stratospheric trends using recent temperature series from Aqua AMSU-A instrument benefits from the fixed orbit of Aqua satellite, which eliminates the tidal effect on the trends due to orbital drift. In addition, AMSU has a more distinct weighting functions (vertical half-width of ~10 km) compared to those of SS. GPS-RO is also a well established technique, providing stratospheric temperature profiles at ~1 km vertical resolution with global geographical and full diurnal coverage. We combine the observations from various RO missions processed using EUMETSAT ROM SAF facility - CHAMP, GRACE, COSMIC and Metop A/B - altogether covering 2002-2016 period. AMSU and GPS-RO temperature trends the RO profiles ranging between the tropopause and 35 km were convoluted using AMSU weighting functions (channels 9-13). The altitude, latitudes and seasonal patterns of temperature trends from AMSU and RO appear in good agreement, providing confidence in our estimates. Analysis of both AMSU and RO datasets are in good agreement showing a clear global cooling. A remarkable inter-hemispheric asymmetry with larger cooling trend throughout the Southern hemisphere’s mid-stratosphere and a quasi-null change at the Northern mid-latitudes is reported. In contrast to that, the (sub-)tropical lower stratosphere is shown to be warming in SH during all seasons and cooling in NH from April through December..



Speaker:
Kero Johan

Swedish Institute of Space Physics (IRF)


INTEGRATION OF COMPLEMENTARY OBSERVATIONS USING ARISE2 HIGH-LATITUDE INSTRUMENTS

Authors: Johan Kero, Evgenia Belova (IRF, Sweden); Peter Näsholm, Steven Gibbons (NORSAR, Norway); Pieter Smets (KNMI, the Netherlands); Jens Hildebrand, Rolf Rüfenacht, Gunter Stober, Gerd Baumgarten (IAP-KBORN, Germany); Patrick Espy, Robert Hibbins (NTNU, Norway); Niklaus Kämpfer (UBERN, Switzerland); Tero Raita (Sodankylä Geophysical Observatory, Finland)
We present the current status of the WP4 investigation to combine “whole atmosphere” measurements in validating infrasound corrections to atmospheric models. In this study we focus on data from August 18-20, 2016, a period when all ARISE2 high-latitude instruments providing wind measurements were in operation and covers the altitude range from ~0-100 km. The selected period of time covers three ground-truth events in form of ammunition destruction with known blast weights at Hukkakero, Finland, suitable for infrasound propagation modelling. The instruments providing data in the study in addition to the infrasound arrays in Norway, Sweden and Finland are the ALOMAR RMR lidar and the microwave Doppler WInd RAdiometer (WIRA, currently at ALOMAR), the Esrange MST radar (ESRAD), and meteor radars at Esrange, ALOMAR and in Trondheim.

INITIAL RESULTS FROM THE ARISE2 MICROBAROMETER ARRAY DEPLOYED IN KIRUNA, SWEDEN

Authors: Johan Kero, Lars Eliasson, Ludwik Liszka (IRF, Sweden); Alexis Le Pichon, Elisabeth Blanc (CEA, France); Eric Stempels (Uppsala University, Sweden); Tero Raita (Sodankylä Geophysical Observatory, Finland)
IRF has in collaboration with CEA in October 2016 deployed an array of four MB3 microbarometers in Kiruna, Sweden, at a site where continuous infrasound registrations has been performed since October 1973. The long time-series consist of microphone recordings using a 75-m tripartite array. The current Lidström microphones and digital 18 Hz recording systems has been in operation since 1998. The deployed microbarometer array allows evaluating the microphone system performance and its detection threshold. The European Arctic contains several sources of ground-truth events such as repeating explosions and mining activity, which provide useful reference. We present initial results from the system comparison, including bolide events recorded on video by the Swedish Allsky Meteor Network enabling a comparison of video and infrasound triangulation and characterisation.



Speaker:
Komenan Benjamin KOUASSI

Geophysical Station of LAMTO/ UFHB


LOCALIZATION OF MICROBAROMS DETECTED BY I17CI AND I11CV IN IMS DATA.

Authors: K.B. Kouassi; A. Diawara and F. Yoroba (Geophysical Station of LAMTO / UFHB)
By using IMS data from 2009 to 2015 of I17CI and I11CV infrasound stations, we study in 0.1Hz to 0.3Hz frequency band, with GPMCC software of NDC-in-Box, the microbaroms in summer et winter periods. We find that the microbaroms detected in winter period by both station comes from the north Atlantic (upper to 30°N). In summer (Jun, July and August), the microbaroms detected are located on equatorial Atlantic band (around 15°N) near the west side of West Africa. Note that, in this zone, the ocean circulation in the upper equatorial Atlantic is composed of vigorous zonal currents. At the surface, there are branches of the North Equatorial Countercurrent (NECC) and South Equatorial Current (SEC) flowing respectively eastward and westward.



Speaker:
Koucká Knížová Petra

Institute of the Atmospheric Physics, CAS, Prague




Speaker:
Kshevetskii Sergey

I.Kant Baltic Federal University, Kaliningrad, Russia


NUMERICAL SIMULATION OF ACOUSTIC-GRAVITY WAVES GENERATED BY ATMOSPHERIC PRESSURE VARIATIONS. THEORY AND APPLICATIONS TO STUDY ATMOSPHERIC-IONOSPHERIC CONNECTIONS.

Authors: Yu.A.Kurdyaeva (Immanuel Kant Baltic Federal University), N.M.Gavrilov(Saint Petersburg State University), S.N. Kulichkov (Obukhov Institute of Atmospheric Physics)
Currently, an international network of high-resolution mikrobarographs for recording wave pressure variations at the surface of the Earth exists. This situation increases interest in the simulation of propagation of waves caused by atmospheric pressure variations. A mathematical theory is developed for solving of a set of primitive nonlinear hydrodynamic equations with given lower boundary conditions in the form of wavelike pressure variations on the Earth's surface. To analyze the correctness of the problem, the equations can be linearized near the ground for small amplitudes of surface wave excitation. The method of wave energy functional shows that in nondissipative approximation the solution of the boundary problem is uniquely determined by variations of the pressure field on the Earth’s surface. The respective dissipative problem has a unique solution with appropriate choice of additional lower boundary conditions for temperature and velocity components. To test the numerical algorithm, two analytical solutions (corresponding to acoustic and gravity wave modes) of the linearized equations are used. Reasonable agreements of numerical and analytical solutions are demonstrated. The developed computer code is used for simulation of atmospheric wave propagation from the experimentally observed pressure variations on the Earth's surface up to the high atmosphere and the effects of these acoustic-gravity waves in the high atmosphere and ionosphere are studied.



Speaker:
Kulichkov Sergey

OBUKHOV Institute of Atmospheric Physics RAS


«INFRASOUND PROPAGATION IN THE ATMOSPHERE: THEORY AND THE EXPERIMENT»

Authors: Sergey Kulichkov, Obukhov Institute of Atmospheric Physics RAS, Pyzhevsky 3, Moscow, 119017, RUSSIA
The problem of study long-range infrasound propagation in the atmosphere by theoretical and experimental methods are discussed. The ray theory, theory of nonlinear acoustic and the method of parabolic equation code to theoretical study of infrasound waves in the atmosphere are used. The surface explosions and volcano eruptions are suggested as the sources of acoustic pulses. The IMS data and the data obtained on other infrasound stations were analyzed for the different events. It was observed that nonlinear effects are sufficiently change the amplitude and dominant periods of infrasound signals at the long distances from the pulsed sources. It was obtained that the effects of partial reflection of infrasound waves from the layered atmospheric structures in the middle atmosphere are the main source mechanism to penetration of infrasound in tha zone of acoustic shadow at the long distances from the pulsed sources. The problem of application of infrasound data to study temperature and wind velocity structure in the middle atmosphere are discussed. The effective sound speed profiles were obtained. For the first time the parameters of the fine-scale layered structure of wind velocity and temperature have been estimated in the stratosphere. It is important to note that the estimates of the vertical gradients of the effective sound speed in the upper stratosphere and lower thermosphere are not available from other remote sensing methods (radars, lidars). The future prospective for using the infrasound monitoring system data is outlined.



Speaker:
Kurdyaeva Yulia

I.Kant Baltic Federal University, Kaliningrad, Russia


NUMERICAL SIMULATION OF ACOUSTIC-GRAVITY WAVES GENERATED BY ATMOSPHERIC PRESSURE VARIATIONS. THEORY AND APPLICATIONS TO STUDY ATMOSPHERIC-IONOSPHERIC CONNECTIONS.

Authors: S.P.Kshevetsky(Immanuel Kant Baltic Federal University), N.M.Gavrilov(Saint Petersburg State University), S.N. Kulichkov (Obukhov Institute of Atmospheric Physics)
Currently, an international network of high-resolution mikrobarographs for recording wave pressure variations at the surface of the Earth exists. This situation increases interest in the simulation of propagation of waves caused by atmospheric pressure variations. A mathematical theory is developed for solving of a set of primitive nonlinear hydrodynamic equations with given lower boundary conditions in the form of wavelike pressure variations on the Earth's surface. To analyze the correctness of the problem, the equations can be linearized near the ground for small amplitudes of surface wave excitation. The method of wave energy functional shows that in nondissipative approximation the solution of the boundary problem is uniquely determined by variations of the pressure field on the Earth’s surface. The respective dissipative problem has a unique solution with appropriate choice of additional lower boundary conditions for temperature and velocity components. To test the numerical algorithm, two analytical solutions (corresponding to acoustic and gravity wave modes) of the linearized equations are used. Reasonable agreements of numerical and analytical solutions are demonstrated. The developed computer code is used for simulation of atmospheric wave propagation from the experimentally observed pressure variations on the Earth's surface up to the high atmosphere and the effects of these acoustic-gravity waves in the high atmosphere and ionosphere are studied.



Speaker:
Laštovička Jan

IAP Prague


LONG-TERM TRENDS IN THE MESOSPHERE AND LOWER THERMOSPHERE

Authors: Institute of Atmospheric Physics CAS, Prague, Czech Republic; jla@ufa.cas.cz
Long-distance propagation of infrasound is realized through the stratospheric and lower thermospheric reflections, thus it depends on background conditions in these two regions. However, contemporary climate change and other long-term change scan change these background conditions. Here I give you, as co-chairman of IAGA/ICMA trend WG and SCOSTEP/VarSITI/ROSMIC trend WG brief overview of trends in the mesosphere and lower thermosphere. These trends are substantially stronger than those in the troposphere. The primary driver is the increasing atmospheric concentration of carbon dioxide but some role is played also by ozone, water vapor, solar and geomagnetic activity. As a consequence of that, trends need not be stable and they can change with time even to opposite trends.



Speaker:
le pichon alexis

CEA, DAM, DIF




Speaker:
Marchetti Emanuele

University of Firenze


INFRASOUND ARRAY MONITORING OF ICELANDIC VOLCANOES: NETWORK EFFICIENCY AND IMPROVEMENTS FOR EARLY WARNING.

Authors: G. Barfucci (Univ. of Firenze), K. Jonsdottir (Icelandic Met. Office), M. Ripepe (Univ. of Firenze), E. Marchetti (Univ. of Firenze),
Infrasound is reflecting the direct coupling of a volcanic source with the atmosphere and is the clear evidence that a volcanic eruption is ongoing. The ARISE project aims to establish an automatic notification system of volcanic eruptions in Iceland, where 4 small aperture, permanent, infrasound arrays have been deployed since 2010 by UNIFI and IMO and are now included into the Icelandic monitoring network. We present here an analysis of the efficiency of the infrasonic network in terms of Early Warning System and we evaluate possible improvements of the actual geometry. The distance of the arrays from active volcanoes is spanning from a minimum of 19 km up to > 200 km, thus resulting into a complex propagation pattern with both tropospheric and stratospheric arrivals to be expected. This results into a time dependent efficiency of the network, caused by the seasonal variation of infrasound propagation and the consequent position and extension of the shadow zones. In order to provide a robust and reliable early warning it is important to be able to detect direct waves that are less affected by seasonal and atmospheric variability than the stratospheric an thermospheric arrivals. Besides, an efficient Early Warning depends on the issue time of the alert.



Speaker:
Marlton Graeme

University of Reading


CONSTRUCTING A GRAVITY WAVE CLIMATOLOGY OVER THE VERTICAL EXTENT OF THE ATMOSPHERE USING DIFFERENT MEASUREMENT TECHNIQUES.

Authors: G.J. Marlton, A.J. Charlton-Perez and R.G. Harrison (Department of Meteorology, University of Reading, Reading, United Kingdom)
Gravity waves are ubiquitous throughout the entire height of the atmosphere, different measurement technologies exist to observe gravity waves over different vertical ranges. However, they are rarely combined to produce a vertical profile of gravity wave activity, let alone show the seasonal variation. Presented here is a vertically varying seasonal gravity wave climatology at Haute Province Observatorie (OHP) . At the surface infrasound arrays will be used to derive gravity wave parameters from a combination of infrasound data and meteorological from the array. In the lower stratosphere, 10-30km, radiosonde profiles from a co-located operational radiosonde site will be used to infer gravity wave properties. A wavelet analysis of the wind and temperature profiles is used to decompose the gravity wave field into individual wavelets for hodographic analysis. At 30-80km the stratospheric temperature lidar, which can observe changes in the density of the air in the profile, will be used to observe gravity waves by looking at the temperature fluctuations. At 85km airglow images can also be used to infer gravity wave information. Seasonal gravity wave parameters from each of these measurement techniques will be analysed, to build a picture of the gravity wave climatology from all 4 measurement systems which occur due to the upwards propagation of gravity waves. Comparisons will also be made with satellite observations of gravity wave momentum fluxes



Speaker:
mejri chourouk

centre national de cartographie et de télédétection


STUDY OF THE PERFORMANCE OF THE INFRASOUND STATION IS48TN DURING THE PERIOD 2011-2017

Authors: Naima Friha,Nouredine Kanzari, Atef Bilel,Saoussen Souayeh,Chourouk Mejri (centre nationale de la cartographie et de la télédetection, DAD, Tunis )
The infrasound station IS48TN, in kesra,Tunisia is part of the verification regime for the comprehensive nuclear-test-ban Treaty. IS48TN is managed and maintained by the Tunisian NDC.Its good location in the middle of the mediterranean Sea allows to have various and interesting detections. Several events were recorded and identified. But since 2010, the performance of the station has began to be noisy, due to a leakage in the pipe array,despite efforts to solve the issue through the pressure test and maintenance. To this issues , Pts decided to upgrade the WNRS at IS48TN.



Speaker:
Mendelewski Christian

Cea




Speaker:
Mialle Pierrick

CTBTO




Speaker:
MILLET Christophe

CEA




Speaker:
Mošna Zbyšek

Institute of the Atmospheric Physics, CAS, Prague




Speaker:
Naima Friha

centre national de cartographie et de télédétection




Speaker:
OLIVIER Nathalie

SEISMO WAVE




Speaker:
POL Katy

CEA




Speaker:
Shaw-Taberlet Jennifer

Wavestone




Speaker:
Sokolova Inna

Institute of Geophysical Research


THE DATABASE OF GROUND-TRUTH INFRASOUND SIGNALS BY DATA OF KAZAKHSTAN MONITORING NETWORK

Authors: I.N. Sokolova, A.A. Smirnov (Institute of Geophysical Research, Republic of Kazakhstan)
In 1994, a contemporary digital network of seismic and infrasound stations was established in Kazakhstan. Successfully operating network is located throughout the perimeter of the Republic territory. At the present time, KNDC receives in real time and processes data from 4 infrasound arrays: Aktyubinsk IS31 (in the west of Kazakhstan), Kurchatov KURIS (in the east of Kazakhstan on the territory of the Semipalatinsk Test Site), Makanchi (in the east of Kazakhstan), and Zalesovo IS46 (Russian Federation). Using data of these stations, infrasound events are detected automatically, and an infrasound events bulletin is created on a regular basis. At the present time, the issue of appropriate parameters selection for events location and identification of infrasound sources is topical. In this regard, it was decided to create a database of infrasound events basing on the infrasound signals from powerful quarry blasts with known parameters. The created database can be used for solving different monitoring tasks, such as calibration of infrasound stations, discrimination of infrasound signal source, precision of explosion parameters, determination of explosion yield and other.



Speaker:
Turunen Esa

Sodankyla Geophysical Observatory


SUPPORT TO ARISE CONCEPT IN FINLAND BY SODANKYLA GEOPHYSICAL OBSERVATORY

Authors: E. Turunen( Sodankylä Geophysical Observatory, University of Oulu, Finland)
Sodankyla Geophysical Observatory (SGO) of University of Oulu, Finland, carries out geophysical measurements and related research at high latitude in the Arctic for more than 100 years now. In addition to hosting one of the instrument arrays of Swedish-Finnish Infrasound Network, SGO has several instruments, which produce continuous aeronomical data from mesosphere and thermosphere and would support the ARISE concept. Hosted instruments include a Fabry-Perot interferometer by University College London for thermospheric winds, SKiYMET meteor radar for winds in mesosphere-lower thermosphere and all sky cameras including a new fast 100 Hz camera by ISEE/ Nagoya University. We emphasize new opportunities using latest remote sensing of the upper atmosphere by advanced radio methods. New software-defined-radio type of instruments include the Kilpisjarvi Atmospheric Imaging Receiver Array, KAIRA facility, which serves as a platform to develop EISCAT_3D type radar reception by simultaneous multiple beams and offers a world-wide new instrumental method, spectral riometry which is a wide-band imaging radiometer method revealing altitude profile of electron density. Spectral riometry will be implemented on the new riometer network, which is under construction. SGO has been running an ionospheric vertical sounder since 1957 and the data was used to study the long-term cooling of the thermosphere. SGO has developed a small version of SDR-based receiver for its current ionospheric chirp sounder and will in future make mapping of ionosphere in larger spatial scales by oblique soundings with a network of these receivers. In collaboration with Finnish Meterological Institute, satellite tomography method is enhanced by a new network of receivers, which allow 3D reconstructions of F-region electron density. SGO also actively participates in developing the next generation incoherent scatter radar EISCAT_3D, which is a phased-array facility with several tens of thousands of antennas, to be distributed in 3 stations across 3 countries in Northern Scandinavia. EISCAT_3D will be a vector imaging radar studying the geospace and atmospheric environment, supporting studies of couplings between space environment and atmospheric layers. EISCAT_3D will be capable of measuring true 3D volumetric wind fields continuously at mesospheric altitudes. SGO's Radio Science Laboratory develops also stand-alone precursor measurements which use EISCAT_3D principles before the construction of EISCAT_3D. One of the main research interests of SGO is the influence of solar forcing on climate and weather. SGO has developed a detailed coupled neutral and ion-chemistry model, the Sodankylä Ion Chemistry model (SIC), which today is also incorporated as a module in the Whole Atmosphere Community Climate Model, WACCM. The currently well-validated SIC model could be used to enhance interpretations of data from the ARISE research infrastructure, in order to study interplay of chemistry and dynamics in the middle and upper atmosphere.



Speaker:
Wallenstein Nicolau

FGF-IVAR


THE 16TH TO 22ND MAY 2016 MOUNT ETNA ERUPTIVE ACTIVITY: INFRASONIC LONG-RANGE OBSERVATIONS AT IS42 STATION, AZORES ISLANDS

Authors: Sandro Matos(1), Emanuele Marchetti(2), Maurizio Ripepe(2) & Nicolau Wallenstein(2) (1)Instituto de Investigação em Vulcanologia e Avaliação de Riscos (IVAR),Universidade dos Açores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Açores, Portugal (2) Dipartimento di Scienze della Terra, Università di Firenze, Via G. La Pira, 4, 50121, Firenze, Italy
IS42 is located in the Azores islands, in the middle of the North Atlantic and is one of International Monitoring System (IMS) infrasound stations, able to detect reliably 1-kiloton explosions at ranges of up to 3000 km or more. On the behalf of the ARISE2 project, collaborative research between UNIFI and the University of the Azores, towards the characterization of extreme atmospheric events, allow to analyze detections on the station records that were attributed to Mt. Etna. Recent volcanic activity is typically effusive with explosive episodes and lava fountaining, with often-large ash ejection in the atmosphere which generate weak (<20 Pa at 6 km) infrasound (Ulivieri, et al. 2013). In the period between December 2015 and May 2016, two large explosive phases lasting 5 days each occurred. We show how only the second episode were recorded at IS42. We present the comparison of infrasound recorded at IS42 station with data recorded near the source by ETN local infrasonic array. Keywords: ARISE2, infrasound, North-Atlantic, IS42, Etna



Speaker:
Šindelářová Tereza

Institute of the Atmospheric Physics, CAS, Prague