scholarly journals How Can the International Monitoring System Infrasound Network Contribute to Gravity Wave Measurements?

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 399 ◽  
Author(s):  
Patrick Hupe ◽  
Lars Ceranna ◽  
Alexis Le Pichon
Keyword(s):  
Monitoring System ◽  
Deep Convection ◽  
Weather Prediction ◽  
Correlation Method ◽  
International Monitoring System ◽  
Wind Noise ◽  
Wave Measurements ◽  
International Monitoring ◽  
Energy And Momentum ◽  
The Tropics

Gravity waves (GWs) propagate horizontally and vertically in the atmosphere. They transport energy and momentum, and therefore GWs can affect the atmospheric circulation at different altitude layers when dissipating. Thus knowledge about the occurrence of GWs is essential for Numerical Weather Prediction (NWP). However, uniform networks for covering GW measurements globally are rare, especially in the troposphere. It has been shown that an infrasound station of the International Monitoring System (IMS) infrasound network is capable of measuring GWs at the Earth’s surface. The IMS was deployed for monitoring the atmosphere to verify compliance with the Comprehensive Nuclear-Test-Ban-Treaty. In this study, the Progressive Multi-Channel Correlation Method (PMCC) is used for re-processing up to 20 years of IMS infrasound recordings in order to derive GW detections. For this purpose, two alternative PMCC configurations are discussed, covering GW frequencies equivalent to periods of between 5 min and 150 min. These detections mainly reflect sources of deep convection, particularly in the tropics. At mid-latitudes, coherent wind noise more often produces spurious detections. Combining the results of both configurations provides a global dataset of ground-based GW measurements, which enables the calculation of GW parameters. These can be used for improving NWP models.

Global gravity wave detections at infrasound stations of the International Monitoring System

2020 ◽  
Author(s):  
Patrick Hupe ◽  
Lars Ceranna ◽  
Alexis Le Pichon
Keyword(s):  
Monitoring System ◽  
Deep Convection ◽  
Weather Prediction ◽  
Low Frequency ◽  
Correlation Method ◽  
International Monitoring System ◽  
Wind Noise ◽  
Global Gravity ◽  
International Monitoring ◽  
Energy And Momentum

<p>Atmospheric gravity waves (GWs) transport energy and momentum horizontally and vertically. The dissipation of GWs can modify the atmospheric circulation at different altitude layers. Knowledge about the occurrence of GWs is thus essential for Numerical Weather Prediction (NWP). However, uniform networks for global GW measurements are rare, and satellite observations generally allow to derive GW parameters in the middle and upper atmosphere only. The barometric sensors of the International Monitoring System (IMS) infrasound network can potentially fill this gap of global GW observations at the Earth’s surface. This infrasound network has been established for monitoring the atmosphere to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty.<br>Two alternative configurations of the Progressive Multi-Channel Correlation Method (PMCC) are discussed for deriving GW detections from the differential pressure data. These configurations focus on GW frequencies equivalent to periods of between 5 min and 150 min. This range covers sources of deep convection, particularly in the tropics, whereas at mid-latitudes, GWs are hard to distinguish from other low-frequency signals, e.g. coherent wind noise. Challenges and perspectives of using the IMS infrasound data for deriving ground-based GW parameters useful for NWP will be discussed.</p>

scholarly journals A Multi-Technology Analysis of the 2017 North Korean Nuclear Test

2018 ◽  
Author(s):  
Peter Gaebler ◽  
Lars Ceranna ◽  
Nima Nooshiri ◽  
Andreas Barth ◽  
Simone Cesca ◽  
...  
Keyword(s):  
Monitoring System ◽  
Body Wave ◽  
Test Site ◽  
Nuclear Test ◽  
International Monitoring System ◽  
Seismic Stations ◽  
Technology Analysis ◽  
Tnt Equivalent ◽  
International Monitoring ◽  
Strong Surface

Abstract. On September 3rd 2017 official channels of the Democratic People's Republic of Korea announced the successful test of a thermonuclear device. Only seconds to minutes after the alleged nuclear explosion at the Punggye-ri nuclear test site in the mountainous region in the country's northeast at 03:30:02 (UTC) hundreds of seismic stations distributed all around the globe picked up strong and distinct signals associated with an explosion. Different seismological agencies reported body wave magnitudes of well above 6.0, consequently estimating the explosive yield of the device in the order of hundreds of kilotons TNT equivalent. The 2017 event can therefore be assessed being multiple times larger in energy than the two preceding events in January and September 2016. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods. Seismological investigations locate the event within the test site at a depth of approximately 0.8 km below surface. The radiation and generation of P- and S-wave energy in the source region is significantly influenced by the topography of the Mt. Mantap massif. Inversions for the full moment tensor of the main event reveal a dominant isotropic component accompanied by significant amounts of double couple and compensated linear vector dipole terms, confirming the explosive character of the event. Analysis of the source mechanism of an aftershock that occurred around eight minutes after the test in the direct vicinity suggest a cavity collapse. Measurements at seismic stations of the International Monitoring System result in a body wave magnitude of 6.2, which translates to an yield estimate of around 400 kilotons TNT equivalent. The explosive yield is possibly overestimated, since topography and depth phases both tend to ehance the peak amplitudes of teleseismic P-waves. Interferometric Synthetic-Aperture-Radar analysis using data from the ALOS-2 satellite reveal strong surface deformations in the epicenter region. Additional multispectral optical data from the Pleiades satellite show clear landslide activity at the test site. The strong surface deformations generated large acoustic pressure peaks, which were observed as infrasound signals with distinctive waveforms even in distances of 400 km. In the aftermath of the 2017 event atmospheric traces of the fission product 133Xe have been detected at various locations in the wider region. While for 133Xe measurements in September 2017 the Punggye-ri test site is disfavored as source by means of atmospheric transport modeling, detections in October 2017 at the International Monitoring System station RN58 in Russia indicate a potential delayed leakage of 133Xe at the test site from the 2017 North Korean nuclear test.

Infrasound station IS25 of the International Monitoring System of the Comprehensive Test Ban Treaty : from design to certification

2021 ◽  
Author(s):  
thomas philippe ◽  
sylvain carre
Keyword(s):  
Monitoring System ◽  
International Monitoring System ◽  
Comprehensive Test Ban Treaty ◽  
Monitoring Tools ◽  
International Monitoring ◽  
Deep Forest ◽  
International Data ◽  
Comprehensive Test ◽  
Test Ban ◽  
Test Ban Treaty

<p>CEA is operating the French segment of the International Monitoring System of the Comprehensive Test Ban Treaty (CTBT). Construction of IMS stations was started on the late 90’ and one last station was pending before completing commitment of France.</p><p>Taking into account experience learned over the years, design was thought to combine enhanced detection capability and robustness. It gives also the opportunity to improve out monitoring tools and technics.</p><p>Station run 9 sensors spread out on a deep forest in Guadeloupe; power is distributed with buried cable while data are received with optical fibre to a central facility from which frames are sent to the International Data Center to the CTBTO. Constructiion was carried out in 2019.</p><p>IS25 was certified by the PTS of the CTBTO in November 2020</p>

Teleseismic slowness-azimuth station corrections for the International Monitoring System Seismic Network

1999 ◽  
Vol 89 (4) ◽  
pp. 989-1003 ◽  
Author(s):  
István Bondár ◽  
Robert G. North ◽  
Gregory Beall
Keyword(s):  
Monitoring System ◽  
Global Network ◽  
Systematic Bias ◽  
International Monitoring System ◽  
Time Data ◽  
International Monitoring ◽  
Event Location ◽  
Systematic Biases ◽  
Predicted Values ◽  
Test Ban

Abstract The prototype International Data Center (PIDC) in Arlington, Virginia, has been developing and testing software and procedures for use in the verification of the Comprehensive Test Ban Treaty. After three years of operation with a global network of array and three-component stations, it has been possible to characterize various systematic biases of those stations that are designated in the Treaty as part of the International Monitoring System (IMS). These biases include deviations of azimuth and slowness measurements from predicted values, caused largely by lateral heterogeneity. For events recorded by few stations, azimuth and slowness are used in addition to arrival-time data for location by the PIDC. Corrections to teleseismic azimuth and slowness observations have been empirically determined for most IMS stations providing data to the PIDC. Application of these corrections is shown to improve signal association and event location. At some stations an overall systematic bias can be ascribed to local crustal structure or to unreported instrumental problems. The corrections have been applied in routine operation of the PIDC since February 1998.

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