Conveners
P1.1 The Atmosphere and its Dynamics
- Braden Walsh (CTBTO Preparatory Commission)
Description
E-poster session with display of each e-poster on an assigned touchscreen
The International Monitoring System particulate radionuclide station air sampler is a specialized device designed to detect and measure radioactive particles in the atmosphere. It forms part of a global network tasked with monitoring adherence to the Comprehensive Nuclear-Test-Ban Treaty. By continuously sampling the air, these stations play a crucial role in detecting unauthorized nuclear...
In theory, infrasound signals generated by bolides offer a window into understanding source properties, such as shock altitude and energy. However, to accurately leverage these signals, both ground truth and accurate atmospheric specifications are essential, as dynamic atmospheric variations over minutes to hours can affect signal viability, and complex propagation paths may lead to unexpected...
Multiscale atmospheric transport models (ATM) resolve mesoscale meteorology, such as frontal passages, and microscale meteorology near-source, which is often strongly influenced by complex terrain and heterogeneity of the land surface. The ability of material collection stations to detect passing plumes can be strongly influenced by local variations in atmospheric flow, particularly nearby the...
In the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Côte d’Ivoire benefits from two primary stations: seismic (PS15) and infrasound (I17CI) respectively for monitoring underground and airborne nuclear tests. Upgrading the infrasound station I17CI from four to more sensors is part of the CTBTO’s medium term objectives. Thus, this research...
The propagation of infrasound through the atmosphere is highly sensitive to small scale disturbances that can significantly influence waveforms. Among these, gravity waves play a critical role and are typically parameterized in General Circulation Models (GCMs). This study investigates the performance of long range infrasound modeling in reconstructing non-orographic gravity waves fields. We...
Anomalously fast infrasound phases, with unexpectedly high celerities, present a challenge for accurate modeling and detection of atmospheric events over long distances. While fast arrivals are typically confined to short-range propagation (within 300 km) where boundary layer effects are dominant, recent observations reveal celerities exceeding 330 m/s at ranges spanning thousands of...
The Strateole2 campaign deployed superpressure balloons for several weeks in the southern stratosphere. On 15 January 2022, their pressure sensors detected infrasound signals (0.01 to 1 Hz) from the major eruption of the Hunga Tonga Hunga Ha'apai (HTHH) volcano. These signals present differences in amplitude and frequency content compared to recording of ground International Monitoring System...
A method for network selection and localization of global infrasound sources based on propagation velocities and azimuth deviations of infrasound signal arrivals at the infrasound stations of the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is developed. The method uses a network likelihood ratio approach, incorporating the Revised Event Bulletin...
Infrasound is one of four technologies dedicated to monitor nuclear explosions. It is used as well to study other issues for the benefit of science or to improve human life. Nowadays, rainfall variability is a widely discussed topic due to climate change. This work probes the relationship between rainfall variability and the characteristics of infrasound signals recorded during the dry season...
The results of theoretical and experimental studies of the fine-scale layered structure (anisotropic turbulence) of the middle atmosphere (20-140 km) using the acoustic method are presented. Based on the developed model, the possibility of formation of a fine-scale layered structure of the middle atmosphere by internal gravity waves from meteorological fronts is shown. Vertical and horizontal...
Infrasound signals are used to monitor various anthropogenic and natural sources. To determine precise source locations and energy, an accurate model of wind and temperature from the surface up to the lower thermosphere is necessary, hence operational NWP products are of great importance for routine infrasound monitoring activities. However, many of these models focus on tropospheric...
Numerical modeling of the propagation of atmospheric waves before atmospheric storms in the Moscow region was performed. A three-dimensional version of the high resolution nonlinear numerical model AtmoSym was used for the simulation. Experimental observations from a network of four microbarographs located in the Moscow region were taken as a source of disturbances. Wave characteristics of...
The oceanic swell is a global and continuous source of infrasound known as microbaroms. The infrasound stations of the International Monitoring System routinely detect microbaroms depending on acoustic waveguides that form in the middle atmosphere (MA) and the upper atmosphere (UA), roughly between 30 and 120 km. Operational meteorological products are biased at these altitudes essentially due...
Jet stream winds play an important role in our daily weather. Accurate wind and temperature estimations in the upper troposphere can lead to better medium to long term weather forecasts. However, continuous measurement in the upper troposphere poses challenges, resulting in relatively sparse data. This study revisits previous research done in the 1960s and 1970s, on the use of ground based...
One of important challenges the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has been facing is to put an error bar on its atmospheric transport modelling (ATM) simulations. A well-established approach to address this question by the meteorological community is to run, for a given date, multiple simulations. These simulations constitute an ensemble, whose instances, or members,...
