meteorological tsunamis on the pacific coast of north america
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Meteorological tsunamis on the Pacific coast of North America. Fine I.V. .1,2 , Thomson R.E. 1 , Rabinovich A.B. 1,3. 1 Institute of Ocean Sciences, Sidney, Canada 2 Heat and Mass Transfer Institute, Minsk, Belarus 3 Shirshov Institute of Oceanology, Moscow, Russia. Contents. - PowerPoint PPT PresentationTRANSCRIPT
Meteorological tsunamis on Meteorological tsunamis on the Pacific coast of North the Pacific coast of North
AmericaAmerica
Fine I.V.Fine I.V..1,2.1,2, Thomson R.E., Thomson R.E.11 , Rabinovich A.B. , Rabinovich A.B.1,31,3
1 Institute of Ocean Sciences, Sidney, Canada
2 Heat and Mass Transfer Institute, Minsk, Belarus
3 Shirshov Institute of Oceanology, Moscow, Russia
ContentsContents1. Introduction: Tsunamis and meteotsunamis1. Introduction: Tsunamis and meteotsunamis
2. Observations:2. Observations: - 9 December 2005- 9 December 2005 - 13 July 2007- 13 July 2007
- 26 February 2008- 26 February 2008
3. Model: Energetic of the wave generation, major 3. Model: Energetic of the wave generation, major mechanisms and effectsmechanisms and effects
4. Conclusions4. Conclusions
“Rissaga” waves in Ciutadella Harbour (Menorca I.) 15 June 2006
More than 40 damaged boats. Total loss: ~ 30 mln euros.
(Montserrat, Vilibic, and Rabinovich, 2006)
Vela Luka, Croatia, 21 June 1978
134 o 132 o 130 o 128 o 126 o 124 o 122 o
46 o
48 o
50 o
52 o
54 o
Prince RupertLangara
Bella Bella
Port Hardy
Winter Harbour
Pacific Ocean Neah Bay
Seattle
Tacoma
Victoria
La Push
Patricia Bay
Point Atkinson
Tofino
Longview
British Columbia
WA
La Push
Neah BayVictoria
Tacoma
Longview
Seattle
BamfieldPat. Bay
Tofino
Observational sites on the coast of British Columbia and Washington State
December 2005
Friday Harbor
Tacoma
Cherry Point
Toke Point
09/12 06 121812
Seattle
Port Townsend
Port Angeles
Neah Bay
10 c
m
WA Stations
6-min data
Sea
leve
l
Tsunami-like event recorded on 9 December 2009 on the coast of British Columbia
There were no seismic activity nor strong storm in the region.
December 2005
09/1206 12 18
La Push
Se
a le
vel (
cm)
06 12 18 10/12 06
-5
5
0
1
-1
0
2
Air
pre
ssur
e (h
Pa
)
1035
1030
1025
1020
Re
sid
ual
air
pre
ssur
e (h
Pa
)
Original
Residual
Later we found an atmospheric pressure record at La Push showing that the event was forced by an abrupt jump of atmospheric pressure (~2 mb).
12 13 14 15July 2007
Seattle (WA)
Patricia Bay (BC)
Neah Bay (WA)
Port Angeles (WA)
Victoria (BC)
Friday Harbor (WA)
Cherry Point (WA)
10
cmS
ea
leve
l All records have a clear arrival time.
Sea level
Tsunami-like event on 13 July 2007 recorded at tide gages of the WA and BC coast in the Golf area.
12 13 14 15July 2007
Seattle (WA)
Patricia Bay (BC)
Neah Bay (WA)
Port Angeles (WA)
Victoria (BC)
Friday Harbor (WA)
Cherry Point (WA)
10
cmS
ea
leve
l
12 13 14 15July 2007
1010
1015
1020
5 hP
aA
tmo
sph
eri
c p
ress
ure
(h
Pa)
(a)
(b)
T34
Seattle
Tacoma
Longview
Neah Bay
La Push
T31
T18
T20
All records have a clear arrival time.
Atmosphreric disturbances were on nigth time of 13 July and repeated on 15 July 15 with less intersity.
Sea level Atmospheric pressure
Tsunami-like event on 13 July 2007 recorded at tide gages of the WA and BC coast in the Golf area.
Strait of Georgia
VancouverIsland
PB11:26
Vic11:06
SaanichInlet
Thetis I
TI~12:00
Juan de Fuca Strait
49°N
48'
36'
24'
12'
124°W 123°W12' 24' 36' 48' 09 12 15
Time (UTC hrs)
13/07/200711:26
11:06
Se
a le
vel
10
cm
Patricia Bay (BC)
Victoria (BC)
(b)(a)
We analyzed atmospheric pressure records and found the event was forced by disturbance moving northward with speed about 23 m/s
-10h -8h -6h -4h -2h 0h 2h 4h 6h 8h 10h
Time of July 13, 2007
1200
1300
1400
1500
1600
1700
1800
1900
Pre
ssur
e, (
kPa-
1000
)*10
0
a62a134a228a62
2h 3h 4h 5h 6h
Time of July 13, 2007
1300
1400
1500
1600
1700
1800
Pre
ssur
e, (
kPa-
1000
)*10
0
Additional high resolution microbarograph records in the Greater Victoria Area confirmed the previous estimates.
10h 11h 12h 13h
T ime of July 13, 2007, GMT
170
180
190
Pa
tba
y
-1000
0
1000
2000
a124
Comparison of the tide gauge record at Patricia Bay and atmospheric pressure record at the nearby microbarograph station.
Sea level and atmospheric variations started almost simultaneously
The direction and the speed of the moving atmospheric disturbances are in good agreement with the direction and speed of the jet stream in the area of interest.
25 26
February, 2008
Tofino (BC)
Patricia Bay (BC)
Neah Bay (WA)
Port Angeles (WA)
Victoria (BC)
Friday Harbor (WA)
Cherry Point (WA)
20 c
mS
ea le
vel
Point Atkinson (BC)
27 28 29 30Time (hours)
1028
1029
1030
1031
1032
Pre
ssur
e(m
b)
LAPW1_BNEAH_BSEATTLE_BTACOMA_B
02 04 06 08 10 12
Tsunami-like event on 26 February 2008 recorded at tide gages of the WA and BC coast in the Golf area.
The direction (toward east-north) and the speed (~30 m/s) of the moving atmospheric disturbances are also in good agreement with direction and speed of the jet stream in the area of interest.
ModelModel
Similarly to a seismological tsunami, a Similarly to a seismological tsunami, a meteotsunami is forced by a term in the mass meteotsunami is forced by a term in the mass conservation equation conservation equation
tP
gh
t
gt
A
1)( u
u),( yxPA
),,( tyx
Energy generationEnergy generation
dxdyhgE
dxdytP
tE A
22
21
u
Wave energy is generated due to the hysteresis effect.
In a stationary case, when the atmospheric disturbance moves with a constant velocity, the wave energy is not generated.
However, in a non-stationary case the energy is generated permanently feeding propagating waves.
Proudman resonanceProudman resonance
gh
UF
FF
gP
UtxPP
A
AA
,1
)(
2
20
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
F
n=8n=4n=2
edisturbancofscalel
widthbaL
lLn
sin
/
Bathymetry map of the central part of the area
“Supersonic” (red) and “subsonic” (blue) areas for U=30 m/s
The areas of the active energy generation
30 m/s20 m/s
Meteotsunami modelling: The disturbance moves to the north
-3
-2
-1
0
1
2
3
Pat Bay
v=60 km/h, T=10 min
-3
-2
-1
0
1
2
3
Sidney
-3
-2
-1
0
1
2
3
Victoria
0 1 2 3 4 5-3
-2
-1
0
1
2
3
Sooke
-3
-2
-1
0
1
2
3
Pat Bay
v=60 km/h, T=20 min
-3
-2
-1
0
1
2
3
Sidney
-3
-2
-1
0
1
2
3
Victoria
0 1 2 3 4 5-3
-2
-1
0
1
2
3
Sooke
Simulated records at specific locations
-50 -40 -30 -20 -10 0 10 20 30 40 50-50
-40
-30
-20
-10
0
10
20
30
40
50
00.050.10.150.20.250.30.350.40.450.50.550.60.650.70.750.80.850.90.951
The total generated energy (over the entire region) is nearly isotropic. The atmospheric speed is the major factor
The simulated energy as function of atmospheric parameters
ConclusionsConclusions 1. Meteotsunamis are relatively frequent phenomena on 1. Meteotsunamis are relatively frequent phenomena on
the west coast of the US and Canada.the west coast of the US and Canada. 2.Meteotsunami in the area are mainly caused by fast 2.Meteotsunami in the area are mainly caused by fast
moving (20 – 30 m/s) atmospheric disturbances of 1-3 moving (20 – 30 m/s) atmospheric disturbances of 1-3 mb with periods of ~5 min – 2 hrs.mb with periods of ~5 min – 2 hrs.
3. High atmospheric activity (small-scale disturbances 3. High atmospheric activity (small-scale disturbances and buoyancy waves) may last hours and even days. and buoyancy waves) may last hours and even days. The speed and direction of the disturbances correlate The speed and direction of the disturbances correlate well with the speed and direction of the atmospheric jet well with the speed and direction of the atmospheric jet stream.stream.
4. Mountains and instability conditions (occurring mainly 4. Mountains and instability conditions (occurring mainly the night time in summer) are additional important the night time in summer) are additional important factors stimulating the process.factors stimulating the process.
5. The efficiency of the wave energy generation is 5. The efficiency of the wave energy generation is related to the Proudman resonance; with the related to the Proudman resonance; with the atmospheric disturbance speed of 20-30 m/s most atmospheric disturbance speed of 20-30 m/s most of energy is generated at depths of 40-90 m.of energy is generated at depths of 40-90 m.
6. The direction and peak period of the atmospheric 6. The direction and peak period of the atmospheric disturbance propagation are the secondary factors disturbance propagation are the secondary factors influencing the total amount of energy generated in influencing the total amount of energy generated in the area. For some sites these factors can play the the area. For some sites these factors can play the crucial role. crucial role.
Thank you!Thank you!