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EOL Seminar Series

Realtime Infrasound, Pressure, and Meteorological Observations from NSF EarthScope USArray
Frank Vernon

Scripps Institution of Oceanography
University of California at San Diego

NSF Earthscope USArray Transportable Array (TA) network is a portable array of approximately 400 sites deployed on a nearly Cartesian grid spanning nearly 2 million square kilometers, with an average inter-station spacing of approximately 70 km. The TA is rolling across the country starting in 2004 and completing the eastern seaboard this year. While the TA network was originally designed with seismic research interests in mind, since early 2010 the network has been upgraded with atmospheric pressure and infrasound monitoring equipment. Essentially all of the approximately 500 stations are now recording atmospheric phenomena in real-time at 40 sps and 1 sps using Setra 278 barometers, VTI SCP1000 MEMS barometric pressure gauges, and NCPA infrasound sensors.

The US Array pressure data have several unique characteristics that are allowing us to conduct a rigorous analysis of the spatio-temporal variations in the pressure field on time scales of less than an hour across the eastern United States: each sensor is deployed for roughly 2 years as part of a quasi-regular grid covering an eastward rolling swath of the continental United States and in the future providing coverage over Alaska. The reporting resolution of the raw data is not a limiting factor, i.e., ~.001 hPa. The combination of the gridded array and high temporal frequency of the data provides a spatially and temporally unaliased sampling of the perturbation pressure field for wavelengths greater than ~150 km. Observations will be presented from gust fronts, near misses of tornados at individual stations, and of the mesoscale gravity waves showing the value and utility of the US Array pressure data. The 2011 tornado season provided a unique opportunity for realtime monitoring of tornadoes via combined seismic, surface pressure and infrasound observations. The EF5 tornado that devastated Joplin, Missouri on May 22nd of 2011 also passed through Earthscope’s USArray Transportable Array (TA) network. The Joplin tornado passed approximately 2 km south of station T38A, whose location near the town of Joplin allowed for unique observations of the storm. The data presented here will further depict the intensity of the EF5 storm.

 The TA data until recently have not been used extensively in the atmospheric science community. A collaboration with the MesoWest software development team at the University of Utah in early 2012 led to real-time access to the 1 Hz pressure observations from the US Array beginning in March 2012. Data from all TA pressure observations are now retrieved, stored in a relational database as 5 minute averages, and disseminated routinely as part of MesoWest. The pressure data are transmitted as well to the Meteorological Assimilation Data Ingest System (MADIS), which subsequently passes the observations on to the National Center for Environmental Prediction for assimilation of the data into operational numerical weather prediction models. Procedures are in place in MesoWest to automatically update metadata as sensors are decommissioned on the western boundary of the Transportable Array and later redeployed.

Thursday, 20 June 2013, 11:00AM Refreshments 10:45 AM
NCAR-Foothills Laboratory  3450 Mitchell Lane
Bldg 2 Auditorium (Rm1022)

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Thursday, June 20, 2013
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Thursday, June 20, 2013