Tracking Outflows from Severe Thunderstorms Using NSF EarthScope USArray Pressure Sensors

摘要

The NSF Earthscope USArray Transportable seismicnetwork, a dense array of over 400 seismic stationsdeployed in a grid with 75km station spacing, providesreal-time monitoring of seismicity as well as surfacebarometric pressure from instrumentation housed withinenclosed vaults. On June 22~(nd) 2010 several of thestations in North and South Dakota, Nebraska andKansas observed sudden and dramatic increases insurface pressure (～2.0 to 3.5 mb in less than 5 minutes,with a gradual increase following). Doppler radar, localobservations and infrared satellite images confirmed thepassage of severe thunderstorms coinciding with thesepressure jumps. On further investigation, it wasdetermined that the USArray stations observing thepressure jumps were actually observing outflow gustfronts from the thunderstorms. Analysis of additionalsevere thunderstorms events on separate occasionsalso confirms the passage of thunderstorm outflowscoinciding directly with pressure jumps among thevarious USArray stations. The data presented withinthis paper will reveal the temporal nature and speed ofthese outflows using the high-resolution continuous1sps pressure data from several USArray stations as abackbone. Additional data will be provided fromDoppler radar and satellite images as well as localobservations. The overall utility and viability of theUSArray pressure data will then be discussed as asupplemental aid for now-casting severe weatherevents.