CNFG2 2016 – Brest Lucie Rolland, Géoazur/OCA/UCA [email protected] V. Rakoto (IPGP) A. Sladen (Géoazur) P. Lognonné (IPGP)
Observa(on des tsunamis depuis l’espace par sismologie ionosphérique
SEISME = SIGNAL
AIR = AMPLIFICATEUR
troposphère
1 cm/s
~100 m/s
250 km en 7-‐8 min
GPS
L’atmosphère est sensible aux secousses sismiques thermosphère
SEISME = SIGNAL
AIR = AMPLIFICATEUR
troposphère
1 cm/s
~100 m/s
250 km en 7-‐8 min
GPS
L’ionosphère est sensible aux secousses sismiques ionosphère
PLASMA = REVELATEUR
L. Loudet
The ionosphere -‐ an acKve medium
TEC map : GAIM by JPL
4
Images : SOHO
L’ionosphère: un milieu acKf L’ionosphère: un milieu très actif
GNSS satellites
Récepteur GPS bi-‐fréquence
Goo
gle
Eart
h
GEONET : ~1200 récepteurs GPS/GNSS
1 TECU = 1e16 electrons/m2
5
compression
dilataKon
Mesurer les ondes ionosphériques co-sismiques
2 fréquences
Rolland et al. (2011b)
Photo T. Yahagi (GSI)
Données « TEC » filtrées entre 1 to 10 mHz
Vers le haut
Vers le bas
Imager les ondes ionosphériques co-sismiques
compression
dilataKon
Rolland et al. (2011b)
Réponse ionosphérique aux tsunamis
Réponse ionosphérique aux tsunamis Functioning DART buoyNon-functioning DART buoyGPS receiver
Kherani, Rolland et al. (2016)
Réponse ionosphérique aux tsunamis Functioning DART buoyNon-functioning DART buoyGPS receiver
Notre objecKf: Inverser les données ionosphériques pour reconstruire l’onde de tsunami
et u(liser les récepteurs GNSS comme tsunamimètre -‐> ModélisaKon quanKtaKve
Kherani, Rolland et al. (2016)
NAS
A im
age
Les tsunamis génèrent des ondes de gravité atmosphériques
Ondes de gravité
transverses
Ondes de gravité N
ASA
imag
e
http://scienceblogs.com
Force prépondérante: Force d’Archimède
GFD-Online GFD-Online
Force prépondérante: Force de gravité
Modélisa(on du signal – modes propres
© L
ogno
nné
and
Clév
édé
(200
2)
Coïsson et al. (2015)
+25km
-25km
Conception Vidéo: Rolland & Coïsson
Première modélisa(on: observa(on par radio-‐occulta(on GPS-‐COSMIC
Coïsson et al. (2015)
Coïsson et al. (2015)
Première modélisa(on: observa(on par radio-‐occulta(on GPS-‐COSMIC
-1
0
1
Filte
red
TEC
(TEC
U)
-1
0
1
Filte
red
TEC
(TEC
U)
08:28 08:29 08:30 08:31 08:32 08:33 08:34 08:35 08:36 08:37 08:38UT [h:m]
Mesured TEC Modeled TEC
passband : 0.05Hz-0.07Hz
passband : 0.05Hz-0.1Hz
Modélisa(on du signal
Coïsson et al. (2015)
2012/10/28, Mw 7.8
The Haida Gwaii tsunami
Model and video A. Sladen, Géoazur
2012/10/28, Mw 7.8
The Haida Gwaii tsunami
Rolland et al., (2014)
2012/10/28, Mw 7.8
The Haida Gwaii tsunami
Empreinte ionosphérique d’un tsunami
+25km
-25km
Conception Vidéo: Rolland & Coïsson
+47 min.
+47 min. +47 min.
+47 min. +47 min. +47 min.
Comparaison données/modèle
Signal plus faible Signal plus fort
Rolland et al., (2014)
ConcepQon Vidéo: Rolland & Coïsson
RAKOTO ET AL.: TSUNAMI NORMAL MODES RESONANCE X - 61
20
40
60
Latit
ude(
°)140 160 180 200 220
Longitude (°)
Epicenter
Dart 51407
Station radf
a)
20
40
60
20
40
60
140 160 180 200 220
140 160 180 200 220
−0.3
−0.2
−0.1
0.0
0.1
0.2
0.3
dTE
C(T
EC
U)
5 6 7 8 9
Time after Earthquake (Hr)
−0.3
−0.2
−0.1
0.0
0.1
0.2
0.3
dTE
C(T
EC
U)
5 6 7 8 9
Time after Earthquake (Hr)
GPS Data
c)
Synthetics (−11.7 mn)
radf Sat 17 Source USGS /1.0 −2.6 mHz
12
16
20
24
Latit
ude(
°)
200 204 208
Longitude (°)
b)
Dart 51407
Station radf
Sat 29
Sat 17
12
16
20
24
12
16
20
24
200 204 208
200 204 208
−0.3
−0.2
−0.1
0.0
0.1
0.2
0.3
dTE
C(T
EC
U)
5 6 7 8 9
Time after Earthquake (Hr)
−0.3
−0.2
−0.1
0.0
0.1
0.2
0.3
dTE
C(T
EC
U)
5 6 7 8 9
Time after Earthquake (Hr)
GPS DataSynthetics (−11.7 mn)
radf Sat 29 Source USGS /1.0 −2.6 mHzd)
−2.5−2.0−1.5−1.0−0.5
0.00.51.01.52.02.5
Tsu
nam
i hei
ght (
cm)
5 6 7 8 9
Time after Earthquake (Hr)
−2.5−2.0−1.5−1.0−0.5
0.00.51.01.52.02.5
Tsu
nam
i hei
ght (
cm)
5 6 7 8 9
Time after Earthquake (Hr)
Dart buoy Synthetics (−11.7 mn)
e)Dart buoy 51407 Source USGS / 1.0 − 2.6 mHz
Figure 14. a) Map centered on the location of the 2006 Kuril Islands tsunami. b) Map
centered in Hawaii. The black line represents the trace of the radf station and satellite
17 and the white line represents the trace of the radf station and satellite 29 between 5h
and 9h after the Earthquake. c) Perturbed TEC for the station radf and the satellite 17.
d) Perturbed TEC for the station radf and the satellite 17. e) Tsunami height for the
dart buoy 51407. We filtered data and synthetics between 1 mHz and 2.6 mHz. A shift
of -11.7 mn is applied to the normal synthetics.
D R A F T November 13, 2016, 6:47pm D R A F T
Autre événement: Kurils 2006 Mw 8.3
Rakoto et al. (en révision)
Détection des tsunamis depuis l’ionosphère -‐ Un point d’observaKon équipé d’un récepteur mulK-‐GNSS (GPS + Galileo + GLONASS ...) permet de sonder mulKdirecKonnellement l’ionosphère, ce qui est suffisant pour confirmer l’origine tsunamogène de la pertubaKon observée -‐ Les satellites GNSS sondant en amont du tsunami n’observe pas ou peu tandis que ceux qui sondent en aval observe le signal de tsunami -‐ La modélisaKon par sommaKon de modes propres est une méthode physique et rapide permekant de reproduire les propriétés génériques de la perturbaKon ionosphérique tsunamogène
Rolland et al., (2014)
Utilisation tsunamimétrique des données GPS ionosphériques: cas tsunami Haida Gwaii
Sur la base du formalisme des modes propres, inversion par moindres carrés des paramètres de la source sismique (composantes du tenseur des moments) puis reconstrucQon par sommaQon.
4.5 5 5.5 6 6.5−0.4
−0.2
0
0.2
0.4 PRN 07 kosm / 0.2 − 2.6mHz
Time after Earthquake(Hour)
dS
TE
C(T
EC
U)
GPS dataLSQ Inversion
4.5 5 5.5 6 6.5−1.5
−1
−0.5
0
0.5
1
1.5
Time after Earthquake(Hour)
Tsunam
i heig
ht(
cm
)
Dart data 51407LSQ Inversion
X - 60 RAKOTO ET AL.: TSUNAMI NORMAL MODES RESONANCE
20
40
60
Latit
ude(
°)
200 220 240
Longitude (°)
Epicenter
Dart 51407
Station radf
a)
20
40
60200 220 240
16
20
24
Latit
ude(
°)
200 204 208
Longitude (°)
b)
Dart 51407 Station radf
Sat 07
16
20
24
16
20
24
200 204 208
200 204 208
−0.4−0.3−0.2−0.1
0.00.10.20.30.4
dTE
C (
TE
CU
)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
−0.4−0.3−0.2−0.1
0.00.10.20.30.4
dTE
C (
TE
CU
)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
−0.4−0.3−0.2−0.1
0.00.10.20.30.4
dTE
C (
TE
CU
)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
GPS dataSynthetics (point source,−9.5mn)Synthetics (extended source,−9.5mn)
kosm Sat 07 Source USGS /0.2 −2.6 mHzc)
−5−4−3−2−1
012345
Tsu
nam
i hei
ght (
cm)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
−5−4−3−2−1
012345
Tsu
nam
i hei
ght (
cm)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
−5−4−3−2−1
012345
Tsu
nam
i hei
ght (
cm)
4.0 4.5 5.0 5.5 6.0 6.5 7.0
Time after Earthquake (Hr)
Dart buoySynthetics (point source,−9.5mn)Synthetics (extended source,−9.5mn)
d)
Dart buoy 51407 Source USGS /0.2 −2.6 mHz
Figure 13. a) Map centered on the location the 2012 Haida Gwaii tsunami.b) Map
centered in Hawaii. The white line represents the trace of the kosm station and satellite 07
between 4 h and 7h after the Earthquake. c) Perturbed TEC for the station kosm and the
satellite 07. d) Tsunami height for the dart buoy 51407. We filtered data and synthetics
between 0.2 mHz and 2.6 mHz. Both point source and extended source modeling are
shown. As expected the point source modeling give us a too high amplitude. A shift of
-9.5 mn is applied to the synthetics.
D R A F T November 13, 2016, 6:47pm D R A F T
Rakoto et al. (en préparaQon)
24
De nouvelles données en perspective: l’ère du multi-GNSS GPS
Récepteurs mobiles
Récepteurs fixes
QZSS GLONASS Beidou Galileo
Plus de 120 sat. GNSS en 2020 Ionosphere : ~30 points de
mesure par staKon
L’avenir: embarquer des récepteurs GNSS miniaturisés sur des plateformes mobiles
-‐ MiniaturisaKon antennes et
récepteurs -‐ Transmission des données en
temps réel
-‐ Faibles coût et consommaKon
8
The 3-element patch antenna array is shown in Figure 5. Each antenna is connected to an input port of a 3-way RF switch, with the output of the switch connected to the FOTON receiver. The RF switch sequentially selects each of the antennas, which produces a predictable apparent motion in the phase center of the antenna array. This system takes advantage of the 20 cm spacing of the antennas, and the corresponding predictable effect on the carrier phase of the direct signal (line-of-sight) and multipath signals (reflected off of elements of the ISS) in order to mitigate the effects of the multipath signal on the radio occultation measurements. The multipath mitigation measures will initially be performed by post-processing the FOTON GPS data on the ground. However, the system has been designed so that multipath mitigation algorithms may be implemented onboard (within the FOTON receiver), by uploading new firmware to the experiment once it is on-orbit. This more sophisticated operating mode will only be attempted after the minimum success of the experiment has been achieved.
Fig 5. 3-element patch antenna array used for multipath mitigation for the FOTON GPS radio occultation receiver, shown during vibration testing at NRL. The FOTON GPS receiver is the gold
box, lower left. The Aerospace Corporation supplied the patch antennas, and NRL supplied the ground plane.
At the end of FY2014 the FOTON flight unit was delivered to NRL, and in FY2015 the Principal Investigator (S. Powell) travelled to NRL a total of 8 times for a series of hardware and software tests, and for integration with the other elements of the GROUP-C experiment. These tests were devised to test the FOTON receiver and antenna array in as realistic conditions as possible. The tests included vibration testing, thermal cycling in a temperature chamber, and outdoor testing so that the antenna array would be illuminated with realistic GPS signal levels (see Figure 6). This outdoor test was extremely important since the remainder of the testing takes place in controlled laboratory settings, and while similar to the environment expected on orbit, it is extremely challenging to duplicate the outdoor RF environment.
Powell et al. (2015)
Surveiller les tsunamis depuis l’espace
GPS
GPS
Tomographie ionosphérique
Satellite In-‐Situ
Sondeur Dopller
OccultaKon
UV
Merci de votreattentionAi
rglow
LEO
GPS