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Observing the Ionospheric Signature of Ocean Tsunamis Using GPS Total Electron Content

Observing the Ionospheric Signature of Ocean Tsunamis Using GPS Total Electron Content. D. A. Galvan 1 ; A. Komjathy 1 ; M. P. Hickey 2 ; A . Mannucci 1 1 Ionospheric and Atmospheric Remote Sensing Group, NASA Jet Propulsion Laboratory, California Institute of Technology

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Observing the Ionospheric Signature of Ocean Tsunamis Using GPS Total Electron Content

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  1. Observing the Ionospheric Signature of Ocean Tsunamis Using GPS Total Electron Content D. A. Galvan1; A. Komjathy1; M. P. Hickey2; A. Mannucci1 1Ionospheric and Atmospheric Remote Sensing Group, NASA Jet Propulsion Laboratory, California Institute of Technology 2Department of Physical Sciences, Embry-Riddle Aeronautical University

  2. Tsunami-driven Traveling Ionospheric Disturbances(TIDs) From Artru et al., 2005

  3. Motivation:Why add ionospheric observations? • DART buoy system is expensive: • ~$250,000 per buoy to build • DART system cost $12 M to maintain/operate in 2009 (28% of NOAA’s total tsunami-related budget)* • Buoys are sparsely distributed, temperamental • Data available 84% of time, outages due to harsh weather, human error* • GPS Receivers are more abundant, multi-use, low-cost • Additional means of observing tsunamis over a broader area could help to validate and improve theoretical model predictions, contributing to tsunami early warning system. *Government Accountability Office (GAO) report, April 2010 http://www.gao.gov/cgi-bin/getrpt?GAO-10-490

  4. Data Type: Total Electron Content (TEC) from International GNSS System (IGS) stations -30-second TEC data from dual-frequency GPS receivers. -Data processed through Global Ionospheric Mapping (GIM) algorithm at JPL -For simultaneous bias identification/removal (satellite and receiver) ,

  5. Regional Networks GEONET Array Source: Scripps Orbit and Permanent Array Center (SOPAC) GPS Data Archive, UCSD http://sopac.ucsd.edu/cgi-bin/somi4i Source: Japanese GPS Earth Observation Network (GEONET) Array Over 1200 stations http://terras.gsi.go.jp/gps/geonet_top.html

  6. Streaming 1-second data availability Currently up to 130 stations worldwide providing 1-second realtime data. http://www.gdgps.net/, ftp://cddis.gsfc.nasa.gov/pub/gps/data/highrate

  7. Methodology • Estimate arrival time. Use simple 200 m/s projection, model predictions (MOST, Song, etc.) • Process GPS TEC data JPL GIM software. • Apply bi-directional band-pass filter: 0.5 – 5 mHz (33.3 – 3 min period) • Plot filtered TEC as a function of distance/time.

  8. American Samoa Tsunami 9/29/09 Observed at Hawaii Rolland et al., 2010 (GRL) Galvan et al., 2011 (submitted)

  9. American Samoa Tsunami 9/29/09Observed at Hawaii (map plot) Distance from Epicenter Lat UT Sep 29-30, 2009 Lon

  10. American Samoa Tsunami 9/29/09Real-time 1-second data

  11. COSMIC as additional resource

  12. Chile Tsunami 2/27/10Observed at Japan

  13. Chile Tsunami 2/27/10Observed at Japan Distance from Epicenter UT Sep 29-30, 2009

  14. Theoretical Model Results Ocean Surface Displacement (m) Vertical TEC Spectral full-wave model (SFWM), Hickey et al., 2009, using input wave form from Peltier and Hines, 1976, and period/velocity from DART buoy.

  15. Hickey Model Compared with Data Filtered VTEC (TECU) Universal Time (2/28/2010)

  16. Summary • Tsunami-driven TID’s observed via GPS TEC after the American Samoa Tsunami of 9/29/2009 and the Chilean tsunami of 2/27/2010. (Galvan et al., submitted) • Models predict tsunami-driven TID’s. (Occhipinti et al., 2008; Hickey et al., 2009; Mai and Kiang, 2009). • Observations: Typically ~0.1 – 0.5 TECU. • 30-second archived data AND 1-second real-time data available for study, both ground-based and LEO (COSMIC). • Long-term potential for warning system.

  17. Acknowledgements • NASA ROSES Grant # NNH07ZDA001N-ESI(Tsunami Imaging Using GPS Measurements) • Dr. John LaBrecque (NASA HQ) • Dr. Philip Stephens (JPL) • Dr. VasilyTitov and Dr. Yong Wei (NOAA Center for Tsunami Research) • Dr. James Foster (University of Hawaii) • Dr. Giovanni Occhipinti (IPGP, France)

  18. BACKUP SLIDES

  19. JPL’s GIM Ionosphere Algorithm • Data-driven vertical TEC maps based on interpolating GPS slant TEC measurements on global scales (1993 – present): • Solar-geomagnetic reference frame • Shell approximation: extended slab (450 km altitude) • Multiple shells (250, 450, & 800 km altitude) • Map slant TEC measurements to equivalent vertical using obliquity factor • Spatial interpolation: Triangular-grid or Bi-cubic splines • Temporal smoothing: stochastic Kalman filter • Vertical TEC at each vertex treated as a random walk parameter • Initialized with Klobuchar, Bent, or IRI95 model • Simultaneously solve for satellite biases (Tgd) and receiver biases

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