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Dec 11, 2013

Detecting Ionospheric TEC Perturbations Generated by Natural Hazards Using a Real-Time Network of GPS Receivers

Jet Propulsion Laboratory California Institute of Technology

M/S 238-600 4800 Oak Grove Drive Pasadena CA 91109

Email: Attila.Komjathy@jpl.nasa.gov

Attila Komjathy, Yu-Ming Yang, and Anthony J. Mannucci

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Dec 11, 2013

Introduction

•  Natural hazards generate waves in the thermosphere and ionosphere that may be detected using ground and space-based GPS observations

•  There is an abundance of current and future GNSS signals that we can use in a real-time and post-processing modes

•  Our objective is to use GNSS ionospheric data to augment e.g., existing tsunami early warning systems

•  Our goal is to get better understanding of wave propagation properties, acoustic and gravity wave velocities, directions, etc.

•  Physics-based modeling and observational evidence •  We discuss examples of acoustic and gravity waves generated by

•  Tsunamis, earthquakes, TIDs, high and low-latitude disturbances •  Volcanic eruptions and nuclear tests •  Ground explosions, etc.

•  Conclusions

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GPS Network

Altitude

F - region

Electron Density

3

CNEWS stations

Tsunami Ionospheric Signature

Tsunami Waves

CNEWS Progress Report

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Dec 11, 2013

Processing Calibrated Slant TEC Observations at JPL

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•  De-trend slant TEC measurements using 10th order polynomial fit •  Filtering slant TEC observations using Butterworth band-pass filter

with 3 and 33 minutes periods •  Display filtered and de-trended TEC observations •  Cross-correlate filtered TEC time series between adjacent tracks to

estimate phase shift. Using distance between corresponding IPPs, compute time difference and speed for acoustic and gravity waves

•  All modules are written is Python •  Processing 1200 sites takes less than an hour •  Package is designed to process and analyze large datasets for rapid

research and analysis following major earthquake events. •  Capabilities used to process data following other natural hazards

including earthquakes, tsunamis, volcano eruptions and controlled nuclear tests

Komjathy, A., D.A. Galvan, P. Stephens, M.D. Butala, V. Akopian, B.D. Wilson, O. Verkhoglyadova, A.J. Mannucci, and M. Hickey (2012). “Detecting Ionospheric TEC Perturbations Caused by Natural Hazards Using a Global Network of GPS Receivers: the Tohoku Case Study.” Earth, Planets and Space, Special Issue on “The 2011 Tohoku Earthquake” Vol. 64, pp. 1287–1294, 2012, doi:10.5047/eps.2012.08.003.

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Elevation Angle Dependence

Local Time Dependence

GPS Only

Pre-dawn activity? Unlikely as GLONASS shows no activity (next slide)

GPS IPPs

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Elevation Angle Dependence

Local Time Dependence

GLONASS Only GLONASS IPPs

No activity

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Real-Time GAIM TEC Residuals for Tohoku Earthquake on March 11, 2011

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GIM residuals (a) and band-pass filtered slant TEC measurements. Panel (b) indicates an example for filtered TEC observations.

NASA’s GDGPS R&D role is highly valuable and gratefully acknowledged

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IGS Station DAEJ

Epicenter to DAEJ distance is about 560 km

~15 min

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Feb 12, 2013 North Korea Nuclear Test

Day Before Day of Event

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Dec 11, 2013

IGS Station SUWN

Test

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Feb 12, 2013 North Korea Nuclear Test

Day Before Day of Event

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http://upload.wikimedia.org/wikipedia/commons/0/02/Trajectory_of_Chelyabinsk_meteoroid_en.png

The Chelyabinsk fireball entered the atmosphere at 3:20 UT on Feb 15 moving at a speed of about 20 km/s. The object, which was several meters in diameter, then burst into pieces at a height of 30-50 km above the ground.

Three consecutive explosions shattered the meteor further. Large fragments moving at a high speed caused a powerful flash and a strong shockwave, with most of its energy released at a height of 5 to 15 km above the earth, with the atmosphere absorbing most of that energy.

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Dec 11, 2013

Day before Day before

Day of impact Day of impact

Chelyabinsk

Chelyabinsk

Impact time

IPP locations at 30 sec IPP locations at 30 sec

A B

C D Day of impact C

Chelyabinsk

Delta TE

C In TE

CU

Delta TE

C In TE

CU

Delta TE

C In TE

CU

Delta TE

C In TE

CU

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The Explosion around 8 PM Local Time in West, TX (UT 2:00 on Apr 18)

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West, Texas Fertilizer Plant Explosion

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Data Collected from About 45 GPS Receivers Near West, Texas

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West, TX

No geomagnetic activity occurred on Apr 17-19, 2013

GPS data downloaded from public GPS data archives

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Processing Data for Day Before the Explosion: Apr 17, 2013 – Establishing a Baseline

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Day before – a very quiet ionosphere: no apparent TEC disturbances

All stations observing all satellites

Longitude dimension collapsed West, TX

TEC

perturbations

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GPS 38

The Day of the Fire and Explosion: Apr 18 All stations Observing Single Satellites

GPS 44

Acoustic waves likely generated by the explosion

Gravity waves

Gravity waves likely generated by the fire

1)  We observe slower gravity waves (~300 m/s) during the fire prior to explosion 2)  And faster (~1000 m/s) acoustic waves following the explosion

TEC

perturbations

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The Global Ionosphere-Thermosphere Model (GITM)

GITM solves for: �  6 Neutral & 5 Ion Species �  Ion and Electron Velocities �  Neutral, Ion and Electron Temperatures �  Non-hydrostatic model with flexible resolution

Ridley, A., Deng, Y., and Toth, G. J. Atmos. Solar-Terr. Phys., 2006.

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Model: GITM Domain: 200 Lon X 100 Lat Resolution: 0.20 Lon X 0.20 Lat Apply cosine wave oscillation to the east wind at the lower boundary (100km) : Amplitude: 30 m/s

Veast = 30 ⋅cos2πλx −ωt

#

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&

'(

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Near- and far-field generated TEC perturbations using 0.1 and 0.5 meter surface displacements simulated by JPL-GITM

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Modeling TEC Perturbations Generated by Natural Hazards

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Comparison between day-time and night-time simulations suggest that CNEWS may be sensitive to measure TEC perturbations during night-time.

Modeling TEC Perturbations Generated by Natural Hazards

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Comparison for GPS and CNEWS Tsunami Height Retrievals

CNEWS Progress Report

Illustration for expected tsunami wave height retrieval using CNEWS and GPS

GPS error bar

CNEWS error bar

Potential error sources to take into account

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Conclusions

•  Various natural hazards may be observed using TEC data from ground and space-based GPS observations

•  Tsunamis, earthquakes, volcanic eruptions, meteor impacts, industrial explosions generate atmospheric waves that we can use to learn about wave propagation properties

•  Fully coupled ocean-thermosphere-ionosphere model development is in progress •  First modeling results seem to be consistent with observed neutral

density and ionospheric perturbations •  Acoustic and gravity waves, their frequencies and occurrences need

to be further investigated •  We use NASA’s real-time GDGPS system to observe natural

hazards to augment existing early warning systems •  Same technology may to used to monitor nuclear tests and

accidental explosions. •  NASA HQ and NASA ROSES Grant (NNH07ZDA001N-ESI) are

gratefully acknowledged

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