Conveners
T1.1 e-poster session: e-poster session - T1.1 - The Atmosphere and its Dynamic
- Pierrick Mialle (CTBTO Preparatory Commission, Vienna, Austria)
T1.1 e-poster session: T1.1 - The Atmosphere and its Dynamic
- Pierrick Mialle (CTBTO Preparatory Commission, Vienna, Austria)
Description
T1.1
In this study, a comparison is made between in-situ infrasound recordings in the microbarom band and simulations using a microbarom source model. The recordings are obtained by the 'Infrasound-Logger' (IL), a miniature sensor that has been deployed as biologger near the Crozet Islands in January 2020. The sensors provide barometric and differential pressure observations that have been obtained...
Sources including volcanic eruptions and buried explosions have been shown to produce directional infrasound radiation. However, infrasound sensor deployments generally consist of instruments placed on the Earth’s surface. Therefore, directional sampling of the radiated acoustic wavefield (especially at angles close to vertical incidence) is generally limited. This insufficient wavefield...
This study presents a vespagram-based approach for comparison between infrasound data recorded at the ground and simulated microbarom soundscapes in multiple directions simultaneously. Data recorded during 2014-2019 at the IS37 station in Bardufoss, Norway, have been processed in the framework of velocity spectrum analysis in order to generate images that present a signal power depending on...
This paper investigates the sensitivity of two cumulous convection schemes – Grell and Emmanuel – under RCP8.5 scenario drought severity over Congo Basin (CB). The analysis were conducted using a multiscalar drought indices, standardized precipitation index (SPI) for several time scale –3,6,12,24,48 months –during the decades 2021-2030 ; 2031-2040 ; 2051-2060, and 2071-2080. The results...
This study examines the assessment of the seasonal forecasts of the North American Multi-model Ensemble (NMME) Project in Central Africa (CA) using deterministic and categorical methods focusing on the rainfall variable. This assessment is made for the June through August, March through May, and December through February seasons at 0-5 months, lead-times which are consistent with many regional...
The I48TN is one of the 60 International Monitoring System (IMS) stations of the Comprehensive nuclear Test Ban Treaty Organization (CTBTO) characterized by its location in the heart of the IMS Infrasound network (Figure 1.a). The ability of the IMS infrasound network to detect atmospheric nuclear explosions and other signals of interest is strongly dependent on station‐specific ambient noise....
In this study, the diurnal variation of the rainfall amount, frequency and intensity, and the rainfall with different durations, as well as its intra-seasonal variability are analysed using rainfall data from 18 stations over Ndiaganiao (area located in western Senegal) during the period 2007-2015. Our results show that the mean rainfall amount and frequency peaks are observed around 1800...
The 4 August 2020 tragic Beirut ground truth explosion is of great interest to test the infrasound component of the IMS network, especially in terms of localization accuracy and energy estimation. Although the event was detected by five infrasound IMS stations located from 2 400 km (I48TN, Tunisia) to 6200 km (I11CV, Cape Verde), the early location capability from such a sparse network remains...
Based on observations from monitoring stations or other platforms, unknown atmospheric pollutant emission sources, including source location, strength, and temporal variations, can be estimated using inverse modeling techniques. In such applications, 3D-particle Lagrangian dispersion models are usually employed, and the source-receptor sensitivities are calculated in either forward or...
The objective of this study is to build and then evaluate a statistical model of seasonal forecasts in Cameroon. A study was carried out in the five agro-ecological zones of Cameroon with the test stations of Kaélé, Meiganga, Nkongsamba, Yaoundé and Kribi. This study consisted of developing statistical forecast models at each of these stations which were then evaluated first over their...
While awaiting signals from a nuclear test, the International Monitoring System (IMS) routinely detects many events that are attributed to atmospheric processes and referred to as perturbators or noise. These events, known to cause false detections, are an important source of difficulty in the network processing operated at the International Data Center (IDC). Because many thousands of events...
Acoustic-wave detection from man-made sources like explosions and artillery is of interest both for civilian and military purposes. Infrasound propagation from surface sources is controlled by a complex interplay between source location, winds, atmospheric attenuation, and topography. The seasonal and stochastic variability of stratospheric and tropospheric winds is known to play an important...
Infrasound is one of three waveform technologies of the Comprehensive Test Ban Treaty (CTBT) verification regime. The International Monitoring System (IMS) network records manmade and natural sources of infrasound signals (bolides, spaceflight activity, sonic booms, volcanic eruptions, quarry blasts, earthquakes...). To identify these sources we need to download and process data, and analysts...
As an artificial radionuclide, I-131 rarely appears in a natural environment, while RN22 monitoring system sometimes finds I-131 each year in air samples, especially in winter. The highest I-131 activity is 3 Bq while MDC for HPGe is 0.08Bq. The Gaussian model is applied to backtrack a possible resource of Iodine near RN22. The activity of cosmogenic radionuclide Be-7 in air samples is...
Infrasound research conducted at Los Alamos National Laboratory (LANL) in recent years has included development of tools for signal analysis, propagation modeling, and uncertainty quantification. Many of these tools have been licensed as open source software, made available for download at the LANL Seismoacoustics Github page (https://github.com/LANL-Seismoacoustics), and are utilized by...
An explosion was reported on the 4th of October in the Port of Beirut (Lebanon), by IMS infrasound stations. News reported that the explosion was due to a large quantity of ammonium nitrate stored in the port that exploded (equivalent to around 1.1KT of TNT). The infrasonic signal was observed by several infrasound IMS stations, among them the Tunisian one (IS48). Data was processed with...
Infrasound radiated during periods of weather changes is an almost continuous background against which infrasound monitoring of explosions in the atmosphere is carried out. In this work the results of study of temporal variations of the characteristics of infrasound (amplitudes, coherences, grazing angles, azimuths and horizontal phase speeds) detected during a passage of warm and cold fronts...
Small-scale atmospheric perturbations known as gravity waves (GW) are critical to infrasound propagation simulations as they alter the propagation path of the waves, causing detections at infrasound stations that remain unexplained when only large scale atmospheric features are considered. Therefore, it is important to investigate ways of accounting for these perturbations in the atmospheric...
To solve the ambiguation in corresponding signals from same sources recorded in different arrays, a multi-infrasonic sources location method is proposed. This method is based on the conservation of acoustic momentum in audibility zone during long-range infrasonic propagation in the atmosphere. In a rocket launch observation experiment, progressive multi-channel correlation method is utilized...
IS42 is one of International Monitoring System (IMS) infrasound stations, located in the Azores islands in the North-Atlantic Ocean.
Stromboli volcano is located in a small Italian island in the Mediterranean Sea. It is probably the world's best-known volcano due its spectacular basaltic explosions interspersed by lava fountains up to 250 m occurring every ≈10 minutes. Following the...
Microbarometer arrays are used for the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) using infrasound waves. In addition, the microbarometers also measure pressure variations that are due to various meteorological phenomena with a resolution that exceeds that of typical barometers. The value of these high-resolution observations for the monitoring of extreme weather is...
Nyepi is a rare activity in the world that only exists in Bali, where all of human outdoor activities stop for a day. This study used Nyepi to measure its impact on changes in weather parameters measurement in Bali. The purpose of this study is to see the effect of Nyepi on the ratio of daily average temperature to duration of solar radiation as well as daily average air humidity at four...
Presently, National Institute for Earth Physics operates two infrasound stations deployed on the Romanian territory: IPLOR 4-element array of 0.6 km aperture, and, under cooperation with AFTAC (USA), BURARI 6-element array of 0.7 km aperture.
As many military bases are deployed across Europe and Near East region, signals from supersonic aircraft activity are detected routinely at the Romanian...
The Stromboli volcano is known for its persistent explosive activity, with hundreds of explosions every day ejecting ash and scoria up to heights of several hundreds of meters. Such a mild activity is however punctuated by lava flows and major explosions that represent a much larger hazard. On July 3 and August 28 2019, two paroxysmal explosions occurred at Stromboli, generating an eruptive...
Explosive volcanic eruptions produce powerful infrasound signals that are frequently recorded by the International Monitoring System (IMS). We are developing and testing methodologies to detect, locate, and characterize volcanic infrasound globally using data from the IMS. Challenges remain in attributing an infrasound event to a particular volcano, in part because source locations can be...
The international monitoring system (IMS) of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) has basically completed the planned construction of 60 infrasound stations in the world. The general infrasound signal processing technology of IMS is the progressive multi-channel correlation (PMCC) method, which includes TDOA algorithm. The common limitation of location algorithm based...
An attempt has been made to calculate different thermodynamic parameters to check the severity of thunderstorms during the pre-monsoon season of 2013-2015 in Bangladesh. In this paper, 60 weak to severe thunderstorms events which were recorded by the Bangladesh Meteorological Department (BMD) are investigated. Lifted Index (LI), Showalter Index (SI), Total Total Index (TTI), Convective...
We present recent advances and results of reprocessing the IMS infrasound dataset from its beginning until early 2021. A new implementation of the Progressive Multi-Channel Correlation (PMCC) algorithm enables characterization, with a single processing run, of coherent noise in log-spaced frequency with one-third octave bands from 0.01 to 5 Hz. Such an array processing algorithm enables better...
Since the year 2000 the German Aerospace Center (DLR) facility near Heilbronn, Germany, has conducted main engine tests of the European ARIANE-5 rocket.
Infrasound signals from these tests have regularly been observed during the last two decades at IMS station IS26 at a range of about 320 km in easterly direction.
While a majority of these tests produced signal observations when carried out...
On 4 August 2020, a warehouse of ammonium nitrate exploded in Beirut, Lebanon, leading to loss of life and property. Infrasonic signals from this event have been detected across the Middle East, Europe and North-Africa. The furthest IMS station that detected the signal was IS11 (Cape Verde) at over 6000 km distance.
The features of the observed infrasonic signals were unusual for the time of...
The celerity-range model used for both association and location in the standard automatic and interactive analysis at the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organisation, has not been updated for over 10 years. The NET-VISA automatic association algorithm (Arora et al., 2013) currently providing additional information to IDC analysts, is based on...
