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

Transcription

1 Detecting Ionospheric TEC Perturbations Generated by Natural Hazards Using a Real-Time Network of GPS Receivers Attila Komjathy, Yu-Ming Yang, and Anthony J. Mannucci Jet Propulsion Laboratory California Institute of Technology M/S Oak Grove Drive Pasadena CA Attila.Komjathy@jpl.nasa.gov

2 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

3 Tsunami Ionospheric Signature F - region Tsunami Waves GPS Network CNEWS Progress Report CNEWS stations Altitude Electron 3 Density

4 Processing Calibrated Slant TEC Observations at JPL De-trend slant TEC measurements using 10 th 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 , 2012, doi: /eps

5 GPS IPPs GPS Only Elevation Angle Dependence Pre-dawn activity? Unlikely as GLONASS shows no activity (next slide) Local Time Dependence

6 GLONASS IPPs GLONASS Only Elevation Angle Dependence No activity Local Time Dependence Dec READI 11, 2013 Meeting at AGU

7 s GDGPS R&D role is highly valuable and gratefully acknowledged Real-Time GAIM TEC Residuals for Tohoku Earthquake on March 11, 2011 GIM residuals (a) and band-pass filtered slant TEC measurements. Panel (b) indicates an example for filtered TEC observations.

8 IGS Station DAEJ Epicenter to DAEJ distance is about 560 km Feb 12, 2013 North Korea Nuclear Test Day Before ~15 min Day of Event

9 IGS Station SUWN Feb 12, 2013 North Korea Nuclear Test Day Before Test Day of Event

10 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 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.

11 Day before A B IPP locations at 30 sec IPP locations at 30 sec D Day of of impact impact Day C Impact time Day of impact Delta TEC In TECU Delta TEC In TECU Chelyabinsk Chelyabinsk Delta TEC In TECU Delta TEC In TECU Chelyabinsk Day before

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

13 Data Collected from About 45 GPS Receivers Near West, Texas West, TX No geomagnetic activity occurred on Apr 17-19, 2013 GPS data downloaded from public GPS data archives

14 Processing Data for Day Before the Explosion: Apr 17, 2013 Establishing a Baseline All stations observing all satellites TEC perturbations Longitude dimension collapsed West, TX Day before a very quiet ionosphere: no apparent TEC disturbances

15 The Day of the Fire and Explosion: Apr 18 All stations Observing Single Satellites GPS 38 GPS 44 Gravity waves likely generated by the fire TEC perturbations Gravity waves Acoustic waves likely generated by the explosion 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

16 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 Model: GITM Domain: 20 0 Lon X 10 0 Lat Resolution: Lon X Lat Apply cosine wave oscillation to the east wind at the lower boundary (100km) : # V east = 30 cos% 2π $ λ x ωt & ( ' Amplitude: 30 m/s Ridley, A., Deng, Y., and Toth, G. J. Atmos. Solar-Terr. Phys., 2006.

17 Modeling TEC Perturbations Generated by Natural Hazards Near- and far-field generated TEC perturbations using 0.1 and 0.5 meter surface displacements simulated by JPL-GITM

18 Modeling TEC Perturbations Generated by Natural Hazards Comparison between day-time and night-time simulations suggest that CNEWS may be sensitive to measure TEC perturbations during night-time.

19 Comparison for GPS and CNEWS Tsunami Height Retrievals GPS error bar Illustration for expected tsunami wave height retrieval using CNEWS and GPS CNEWS error bar Potential error sources to take into account CNEWS Progress Report

20 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 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. HQ and ROSES Grant (NNH07ZDA001N-ESI) are gratefully acknowledged