The Addition of Great Britain Storm Surge to
Transcript of The Addition of Great Britain Storm Surge to
1©2019 AIR Worldwide CONFIDENTIAL—FOR WEBINAR ATTENDEES ONLY 1
The Addition of Great
Britain Storm Surge to
AIR’s Extratropical
Cyclone Model for
Europe
Richard M. Yablonsky, Ph.D.
Alastair Clarke, Ph.D.
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Agenda
Introduction
Updates to the Hazard Component
Hazard Model Validation
Updates to the Vulnerability Component
Modeled Losses
Upcoming Software Changes
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Introduction
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History of AIR’s Coastal Flood Model for Great Britain
20132000 20192010
Great Britain
Vulnerability
Update
Addition of
Great Britain
Storm Surge
to EU ETC
Great Britain
Exposure
Update
Great Britain
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Changes in Model Configuration
Previously:
AIR Coastal Flood Model for
Great Britain
2019 Update:
Storm Surge sub-peril in the AIR
Extratropical Cyclone Model
for Europe
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What Is Storm Surge?
Shallow Water Deep Sea
Sea Defenses
Bathymetry
Topography
WindPressure
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Extratropical Cyclones Generate Storm Surge
in Great Britain Historical Storm Tracks
Longitude
Latitu
de
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Historical Events Affect Both the West and East Coasts
Southerly wind pushes water into
Irish Sea
Northerly wind pushes water into
the Channel
Storm Anne (2014): West Coast Example*
*another example is Storm Undine (1991)
Storm Xaver (2013): East Coast Example**
**another famous example is North Sea Flood (1953)
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Updates to the Hazard
Component
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• Expanded domain covers all of England and Wales
• Uses Delft3D Flexible Mesh
• Dynamic simulation of tides
and surge
• Driven by wind and pressure
from EU ETC model catalog (see Keshtpoor, Carnacina, and Yablonsky, 2019: New
Statistical Approach to Select Coastal Flood-Producing
Extratropical Cyclones from a 10,000-Year Stochastic
Catalog. J. Waterway, Port, Coastal, and Ocean Eng.)
• Surge depth at 10-meter
resolution via downscaling
and topography subtraction
New Hydrodynamic Coastal Flood Model
Hydrodynamic Domain Coarse Mesh
Current Coverage
Fine Mesh:
New Coverage
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CORINE Land Use/Land Cover Database
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• Data can be mapped to a Manning friction coefficient
• Helps to ensure proper flood extent over land
• Particularly challenging in urban areas
CORINE Land Use/Land Cover Database
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Incorporation of the Latest Levee Data Sources
• 2016 vintage defense data
set for the entire United Kingdom: defined crest
heights, material, quality
condition, and design type
• Undefined heights were extracted from 2- to10-
meter topography (DTM)
sources
UK Environment Agency Spatial Flood Defences Dataset
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Thames River Defenses
• The Thames Barrier was completed in 1984
• During construction, flood defenses were raised by ~2 meters for ~30 km downstream to match the Barrier
• Defenses for ~5 km upstream were also raised to increase protection and match protection of Central London
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Accounting for Breached Levees in Addition to
Overtopping Levees
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Hazard Model Validation
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Storm Surge Model Validation at Great Britain
Tide Gauges for Four Storms
Tide Gauge Locations
Four Storms Combined:
1953, Undine, Xaver, and Anne
RMSETWL= 0.32 m
RMSEWS = 0.28 m
Observed Water Elevation (Meters)M
od
ele
d W
ate
r Ele
va
tio
n (
Me
ters
)
Total water level
Perfect lineWind setup (no tide)
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Modeled Pressure, Wind, and Surge During
North Sea Flood of 1953
a) Sea level pressure
b) West-to-east wind
speed (U) ~180 meters
above ground
c) South-to-north wind
speed (V) ~180 meters
above ground
d) Water level due to
wind setup (without
tide)
a) SLP (mb) b) U (m/s)
c) V (m/s) d) Surge (m)
60
55
50
60
55
50
Latitu
de
(°)
-10 0 10 -10 0 10
1030
1020
1010
1000
990
980
20
10
0
-10
-20
-30
20
10
0
-10
2
1
0
-1
-2
Longitude(°)
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Modeled Water Level Near Thames Barrier
from a Storm Like the 1953 North Sea Flood
Time (Hours)
Tide Only
Surge Only
Linear Tide & Surge
Total Water Level
8
6
4
2
0
-2
-40 10 20 30 40 50 60 70 80
~7.3 m (height of Thames Barrier)
~5.4 m (like North Sea
1953 storm)
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Flood Extent Validation for the 1953 North Sea
Flood Event (Thames River)
ThamesBarrier
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Flood Extent Validation Along the Humber River
for 2013 Storm Xaver
Hull, UK
Humber
River
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City of Hull Close Up: Storm Xaver in 2013
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City of Hull Close Up: Storm Xaver “Today”
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Boston, UK
The Haven River
Insufficient resolution (~220 m)
for water to reach Boston, UK
Flood Validation for Storm Xaver in Boston, UK:
Fine Mesh Versus Super-Fine Mesh
Boston, UK
The Haven River
Sufficient resolution (up to 35 m)
for water to reach Boston, UK
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Updates to the
Vulnerability Component
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Component-Level Damage Functions
Building
Structure Fixtures Services
Me
an
Da
ma
ge
Ra
tio
Flood Depth
Building Structure
Services
Fixtures and Fittings
Overall Building Coverage
Building and Component Damage
Functions for a Retail Shop
0%
20%
40%
60%
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Reduction in Commercial Building Vulnerability
Relative to Residential
0
0.5
1
1.5
2
2.5
3
Previous Version Updated Version
Re
lativ
e V
uln
era
bili
tyResidential Commercial
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• Addition of marine
cargo, marine hull,
industrial facilities, wind
turbine, and builder’s risk
• Incorporation of
unknown damage
functions at CRESTA level
• Updated secondary
damage distributions
Vulnerability Updates Leverage a Unified
Framework Across Models in Europe
Marine
Industrial Facilities
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Da
ma
ge
Ra
tio
Flood Depth
67K Claims from Four Historical Floods Inform
the Latest Secondary Uncertainty Distributions
• In the new model, there is lower
probability of zero or full
damage
• Distinct secondary uncertainty
distributions for Residential and
Commercial risks
Pro
ba
bili
ty
Damage Ratio
Previous Updated
Mean Damage
Ratio
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Custom Flood Protection
Presence of Basement
Floor of Interest
First-Floor Height
Custom Elevation
Support for New Secondary Risk Characteristics
Foundation Type
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• Utilized best available building
footprint data sets to
accurately locate risks
• Updated construction splits,
replacement costs, coverage
splits, and policy conditions
• Improved automobile
valuation methodology
• Identified high-value industrial
facilities
New Industry Exposures Modeled at 90-Meter Resolution
London, UK
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New Industry Exposures Modeled at 90-Meter Resolution
1 km
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New Industry Exposures Modeled at 90-Meter Resolution
1 km
90 m
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Modeled Losses
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Observed Data Sources: UK Met Office, Munich Re, ABI
Historical Event Loss Validation
0
1
2
3
4
5
6
7
8
9
North Sea Flood (1953 Vintage)
Loss
es
(GB
P B
illio
ns)
Model Ground-Up Estimated
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Historical Event Loss Validation
0
50
100
150
200
250
300
350
400
450
Undine (1991) Xaver (2013 Vintage) Anne (2014)
Loss
es
(GB
P M
illio
ns)
Flood Events
Model Insured Observed
Observed Data Sources: UK Met Office, Munich Re, ABI
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AOL 2 4 5 10 15 20 50 100 200 500 1,000 2,000 5,000 10,000
Loss
Return Period (Years)
Exceedance Probability of Insurable Gross Loss
X = No SoP
V = Vintage SoP
M = Modern SoP
2013 M
2013 V
1953 M
1991
2014
1953 X
1953 V
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AOL 2 4 5 10 15 20 50 100
Loss
Return Period (Years)
Exceedance Probability of Insurable Gross Loss
V = Vintage SoP
M = Modern SoP
2013 M
2013 V
1953 M
1991
2014
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Insured Aggregate Loss Comparison: Adding Surge
AAL 2 5 10 20 25 50 100 200 500 1,000
Loss
Return Period (Years)
Residential, Commercial, Industrial, Agriculture, and Auto
Lines of Business
Wind Only
Wind & Updated
Surge
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Insured Aggregate Loss Comparison: Wind & Surge
AAL 2 5 10 20 25 50 100 200 500 1,000
Loss
Return Period (Years)
Residential, Commercial, Industrial, Agriculture, and Auto
Lines of Business
Wind & Previous
Surge
Wind & Updated
Surge
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Upcoming Software
Changes
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Functional Changes in Touchstone
Touchstone 2018
Touchstone 2019
*
*
* Europe Extratropical Cyclone is still categorized as a “Tropical Cyclone” peril in Touchstone
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1) Events in the Database are tagged as either Extratropical Cyclone (E), Surge (S) or Combined (C).
2) In Touchstone® 2019, you can run the previous and new versions of the GB storm surge model
3) Users can apply financial terms on combined wind and surge losses in Touchstone and CATRADER®/Touchstone ReTM
4) CATRADER/Touchstone Re users can also get losses for the GB surge-only catalog
5) Exported CLFs will be for European ETC (even storm surge-only runs)
Bonus Features in Touchstone and CATRADER/Touchstone Re
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Summary
Added the storm surge sub-peril as part of AIR’s Extratropical Cyclone Model for Europe
Expanded model coverage to include all of England and Wales
Updated with modern-day levee information to improve surge footprints
Enhanced damage functions using claims and peer-reviewed literature
Greater selection of primary and secondary characteristics to represent your risk
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Questions?