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The after-runner storm surge along the north coast of Vietnam simulated by the 2D ROMS model
Nguyen Ba Thuy1, Pham Khanh Ngoc1, Lars R. Hole2, Nils Melsom Kristensen2, Johannes Röhrs2, Cecilie Wettre2
1Vietnam National Center for Hydro-meteorological Forecasting (NCHMF) 2Norwegian Meteorological Institute (MET Norway)
Cape Town, 3-7 April 2017
Storm surge
Anormalyze water level (Meteorological tsunami)
Spring tide (Hight tide
+ surge induced by moonson)
Coastal Dissater related to high water level in Vietnam
High Vulnerable storm surge (abundant typhoon +
shallow water)
Less Vulnerable storm surge (rare typhoon + deep water)
Less Vulnerable storm surge
(shallow water +rare typhoon)
Number of
Typhoon
Possibility Storm Surge in Vietnam
June
Dec.
-0.5
0.0
0.5
1.0
1.5
9/29/2006 6:00 9/30/2006 12:00 10/1/2006 18:00
Sur
ge h
eigh
t (m
)
Time (h)
Observation
Without wave
With waveNumerical Model:
- 2D ROMS + WRF
- SuWAT (Surge Wave and
Tide) + Best track or WRF
Time serial of storm surge
Storm surge research and prediction
Coastal inundation due to tide + storm surge + wave setup
Flooding in Ho Chi Minh City in
20/11/2011 Maximum tide amplitude
Spring tide in Hochiminh city
Spring tide in Hochiminh City is related to Surge induced by
monsoon or not?
It related to flooding in Hochiminh
City on 20/10/2013
-0.5
-0.3
-0.1
0.1
0.3
0.5
0.7
0.9
10/8/2013 0:00 10/14/2013
0:00
10/20/2013
0:00
10/26/2013
0:00
Time (s)
Su
rge
hei
ght
(m
)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Wat
er s
urf
ace
elev
atio
n (
m)
OBS-Total water levelModel-SurgeOBS-Surge
Spring tide in Hochiminh city on 20/10/2013
* Vung Tau
Hochiminh city
Time profile of total water surface elevation, predicted and measure
surge height
Maximum water surface elevation during the monsoon 10/2013
Wind field at 20/10/2013 Spring tide = high tide+ surge (by moonson)
High Oscillation of water level on the middle coast of Vietnam
High tide at Tuyhoa in Dec. 2016
(No typhoon and calm wind. But the
inundunation height up to 1m, and go in
land up to 200m). Meteorological
tsunami?.
Time serial of total water level, tide and surge
To simulate this phenomenal need high resolution of ocean and atmosphere model. Next study
-1
0
1
2
3
4
5
6
12/11/2016 0:00 12/16/2016 0:00 12/21/2016 0:00
Z (c
m)
Time (h)
OBS Tide Surge
The after runner storm surge on the North coast of Vietnam
Area: The north coast of Vietnam
Typhoon frequency: 1.5 typhoons/year
Maximum storm surge: 3.4m
The after runner storm surge: 6 cases/50 years
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
9/16/2014 0:00 9/18/2014 0:00
Stoe
m su
rge
(m)
Time (h)
Storm surge at Hondau station during typhoon Wukong (2005) and Kalmaegy (2016)
Typhoon landfall
Typhoon landfall
Normal storm surge
After runner storm surge
The after runner storm surge
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
7/29/2005 0:00 7/31/2005 0:00 8/2/2005 0:00
Stor
m s
urge
(m)
Time (h)
Observation water level, predicted tide and
storm surge at Hondau station
-50
0
50
100
150
200
250
300
350
400
450
9/16/2014
9:36
9/16/2014
14:24
9/16/2014
19:12
9/17/2014
0:00
9/17/2014
4:48
9/17/2014
9:36
9/17/2014
14:24
9/17/2014
19:12
9/18/2014
0:00
9/18/2014
4:48
9/18/2014
9:36
9/18/2014
14:24
Time (h)
H (
cm)
Total water level
Prediced tide
Surge
Time of typhoon landfall
time interval of
urge exceed 0.5m
The after runner of storm surge cases
Kalmeagi (9/2014)
Mirinae (7/2016)
Typhoon land fall
Inundated
No inundation
- Damage by wind is not much.
- But Storm surge + high tide + high wave
generated inundation at Haiphong coast
after the typhoon landfall 5 hours.
(a)
Typhoon Kalmaegi (9/2014) – After runner storm surge case
High wave and inundation at Haiphong coast
- Empirical Typhoon Model:
fDuy
Dgy
Dv
x
Duv
t
Dv
fDvx
Dgy
Duv
x
Du
t
Du
byay
ww
bxax
ww
)(1)(1
)(1)(1
02
02
0
y
Dv
x
Du
t
2
0)/(1
)(rr
PPPrP c
(Fujita model)
r
Pfv
r
v
12
Operational Forecasting Model in 9/2014
Two dimensional long wave model + Empirical Typhoon Model
Result of Operational forecasting (2D long wave model + Fujita model)
Simulated result showed storm surge not high at Hondau station, and at low tide –> No warning. But infact inundation occurred. We miss warning
Maximum storm surge
Model and observation storm surge
Typhoon track
-1
-0.5
0
0.5
1
1.5
2
9/16/2014 12:00 9/17/2014 12:00 9/18/2014 12:00
Stor
m s
urge
(m
)
Time (h)
OBS
FUJITA
Typhoon Landfall
Storm surge observation data
Time profile of total water, tide and storm surge at Hondau and Honngu station
-100
-50
0
50
100
150
200
250
300
350
9/16/2014 0:00 9/16/2014 18:00 9/17/2014 12:00
Z (
m)
Time (h)
OBS
Prec. Tide
Storm surge
Typhoon Landfall
-50
0
50
100
150
200
250
300
350
400
450
9/16/2014 12:00 9/17/2014 12:00 9/18/2014 12:00
Z(m
)
Time (h)
OBS
Predic. Tide
Storm surge
Typhoon land fall
Simulated the after runner storm surge by (ROMS 2D + WRF)
Domain for WRF model (7km) and ROMS model (2km)
WRF
ROMS
Results of 2D ROMS + WRF model
Comparison of calculated and simulated storm surge at two station using wind and pressure from WRF
ROMS+WRF is well simulated the storm surge at two station -0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
9/16/2014 12:00 9/17/2014 6:00 9/18/2014 0:00
Stor
m su
rge
(m)
Time (h)
OBS
WRF
Typhoon landfall
-1
-0.5
0
0.5
1
1.5
2
9/16/2014 12:00 9/17/2014 12:00 9/18/2014 12:00
Sto
rm s
urge
(m
)
Time (h)
OBS
WRF
Typhoon Landfall
Measured and predicted pressure (above) and
wind speed (below) and at Hondau station
The WRF model simulated well wind and pressure than the
empirical typhoon model
Wind and pressure data
Comparison of calculated and simulated storm surge at two station for two case using WRF model. One using front and tail wind field (above), the other using the front wind field only (below).
Effect of front and tail wind field on storm surge
Storm surge at Hondau station is mostly induced by tail wind. But at Honngu station is due to the inertia force
-1
-0.5
0
0.5
1
1.5
9/16/2014 6:00 9/17/2014 6:00 9/18/2014 6:00Sto
rm s
urg
e (m
)
Time (h)OBS
WRF
WRF-No wind after land fall
No wind after typhoon land fall
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
9/16/2014 0:00 9/17/2014 0:00 9/18/2014 0:00Stor
m s
urge
(m
)
Time (h)
OBS WRF WRF-No wind after landfall
The result at the Honngu station is not so much different between two cases. It means storm surge at Honngu station is due to water moving from North to the south ?.
Maximum storm surge for the case the model using front and tail wind field (left) and front wind field only (right)
Effect of front and tail wind field on storm surge
Honngu
Hondau
At the time typhoon land fall (water level at two station is down) After typhoon land fall 4 hour (water level at Hondau station is going up)
After typhoon land fall 6 hour (water level at Hondau station get maximun)
The tail wind fields of typhoons are more important than front wind fields.
How the surge generated at the Northern part (Hondau station)
Wind and water surface elevation
After typhoon land fall 4 hour (water level at Hondau station is going up)
Water surface elevation and current
Storm surge on the southern part (Honngu station) due to the tail wind
and water moving from the north.
How the surge generate at the Southern part (Honngu station)
Wind and water surface elevation
After typhoon land fall 8 hour
Effect of wind and pressure on storm surge
Comparison of calculated and simulated storm surge at two station for 3 cases of wind + pressure, wind only and pressure only (data from WRF model). The contribution of wind is mainly.
-1
-0.5
0
0.5
1
1.5
9/15/2014 12:00 9/16/2014 12:00 9/17/2014 12:00Stor
m s
urge
(m
)
Time (h)
OBS
Wind and pressure
Win only
Pressure only
Effect of tide storm surge
Comparison of simulated and observation storm surge. The simulated results for two case, with and without consider tide.
Effect of wave on storm surge
Comparison of simulated and observation storm surge. The simulated results for two case, with and without consider wave.
Future works:
- Meteorological tsunami (anormalyze water level) on the middle coast of Vietnam
- Wave and ocean current using radar data (assimilation)
local/rear/tail winds
front winds
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