Summary of 2003 Infrasound Technology Workshop Session Chairs

IMS Network/IDC Processing Rapid growth of IMS network: 23 transmitting, 13 certified, 12 under construction IDC Testbed: 16 current IDC Operations: 11 current Infrasound temporarily out of SHI data fusion process High number of detections Large scale automatic processing in November 2003 Progress in modeling network performance: incorporation of seasonal variance

New Developments Experimentation with new array configurations Noise filtering at extreme wind (> 40m/s) Monitoring of volcanic eruptions and hurricanes Improved characterization of specific heat ratio of the atmosphere up to heights of 160 km Improvement of ANSII standard for attenuation coefficient at low frequencies and high altitudes

New Developments GINA prototype is available to infrasound community InfraMatics, AGU and AGU monograph Progress in IIC: Collaborations are invited

Sources Discrimination between stationary and moving sources Studies of bolides, eruptions, MAW, aurora, microbaroms, earthquakes, ice avalanches, surf, man-made signals More work needed in detection, characterization, far and near-field location

Modeling Propagation modeling of signals from Columbia and explosions Source modeling of microbaroms Improvements in location and full wave modeling of infrasonic signals Time-domain PE (broadband modeling) Direct time-domain solutions of the wave equation Use of improved atmospheric estimates Need for implementation of improved absorption models

Processing Impact of noise levels on detection rate Importance of using more accurate atmospheric models for source localization Automatic associations, detection statistics, clutter rejection Data sets assembled for ROC curve analysis Studies of the relationship between array configuration/location and performance of detection and estimation algorithms Correlation detectors effective and robust Detection: recognize a signal is present - correlation detectors work well Estimation: calculation of parameters that describe signal properties

Processing 4D location of atmospheric explosions using ground observations of acoustic waves. GT data key to progress in location and characterization. PMCC love fest Deals well with different array geometries Must be optimized to find particular signal features Velocity model key. Use acoustic waves and acoustic coupled to seismic

Noise Reduction Light-speed filters have obvious advantages over sound-speed filters but further research/engineering improvements required Velocity model key. Use acoustic waves and acoustic coupled to seismic

Conclusions Continue to probe at basic, difficult but key, aspects of acoustic source phenomenology, propagation, modeling and reception Data processing must continue to advance rapidly to deal with mushrooming data volume Research community continues to make great progress in array design Essential that these results are used to optimize existing or new IMS stations Velocity model key. Use acoustic waves and acoustic coupled to seismic