Ian ChurchOcean Mapping Group

University of New Brunswick

US Hydro 2007The Sixth International Discussion Group Meeting on

Uncertainty Management in Hydrography

Saint JohnSaint John

DigbyDigby

St. AndrewsSt. Andrews

Grand MananGrand Manan

EastportEastport

2

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land

Cam

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Isla

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The Wolves

St. Andrews

Eastport

3

2.8 m

2.3 m

Pass

amaq

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MacesBay

M2 Amplitude and Phase

WebTide Scotian Shelf Model

1 Minute Phase Contours

8 Minute Phase Lag Through Letite Passage8 Minute Phase Lag Through Letite Passage

0 km 10 km 20 km

White – 0.2m range contours.Black 1 minute phase ranges.

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Operations 2007Grand Manan

M2 Amplitude and Phase

WebTide – Scotian Shelf

ModelContours:1 Minute Phase0.2 m Amplitude

Tides:• Observed Tides• Predicted Tides• Hydrodynamic Model

Sounding Datums:• MSL / Geoid• Local Chart Datum

Discrete Steps? Linear Transition? Polynomial Interpolation?

• Co-Tidal Interpolations• Scaled Multiple of the

Local Harmonic Constituents

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We wish to establish a vertical datum which represents an offset from mean-sea-level, below which “the tide rarely falls”.

Tides in the Bay of Fundywrt Saint John

Options:• Use Predicted Tides • Interpolate Between Stations

Outer Wood Island-15 minutes

-9.5ft

North Head-5 minutes

-5.5ft

Dipper Harbour-2 minutes

-2.6ft

St. Andrews+8 minutes

-2.5ft

St. Stephen+8 minutes

-1.0ft

Partridge Is.-13 minutes

-0.3ft

Welshpool+1 minutes

-4.2ft

Back Bay-7 minutes

-3.8ft

St. Martins+6 minutes

+6.3ft

Cape Enrage+5 minutes

+13.2ft

Hopewell Cape+8 minutes

+18.5ft

Moncton+45 minutes

+26.2ft

Advocate Harbour+5 minutes

+10.3ft

Saint JohnPrimary Port

0 minutesMean Tide – 25.3ft (7.7m)Large Tide – 29.6ft (9.0m)

Margaretsville-18 minutes

+7.6ft

Digby-16 minutes

+1.0ft

Brier Island-44 minutes

-8.3ft

Source:Canadian Tide and Current TablesAtlantic Coast and Bay of Fundy

EastPort MEUSA

Primary Port

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A Digital Replica of the Water Within a Region

Created using a Coastline and Seafloor Bathymetry

Driven Using Topex-Poseidon Tidal Observation Data and Tide Gauge Data

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Scotian Shelf ModelScotian Shelf Model

Bay of FundyBay of Fundy

Nova Scotia

Maine

A TIN of the Scotian Shelf, Georges Bank and the Bay of Fundy DUPONT, F.; C.G. HANNAH, D.A. GREENBERG, J.Y. CHERNIAWSKY and

C.E. NAIMIE. 2002. Modelling system for tides for the North–west Atlantic coastal ocean. Can. Tech. Rep. Hydrogr. Ocean Sci. 221:vii+72pp.

Provides a Tidal Prediction for any point within the TIN

Predicted Amplitude and Phase

Tidal Currents Accuracy

• 0.15 metres Amplitude

• 5 deg Phase

8

Dupont, F., C. G. Hannah, D. Greenberg. Modelling the sea level in the upper Bay of Fundy. Atmosphere-Ocean 43(1) 2005, 33-47.

9 Meteorological Effects – Pressure, Wind/Wave Build up, etc.

Non-Tidal Residuals

DigbyDigby

Saint JohnSaint John

EastportEastport

CutlerCutler

Brier IslandBrier Island

NorthHeadNorthHead

YarmouthYarmouth

Cutler Naval Base - MaineCutler Naval Base - Maine

Digby – Nova ScotiaDigby – Nova Scotia

Eastport - MaineEastport - Maine

Brier Island – Nova ScotiaBrier Island – Nova Scotia

0km 25km 50km 100km

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All Tide Stations within the Area Display Very Similar Non-Tidal Residuals

Non-Tidal Residuals from a Single Station can be Examined

Sounding Datum that Varies Constantly and Smoothly throughout the Entire Model Domain

Based off the Tidal Prediction at Each Node within the TIN

Develop Sounding Datum Based on Hydrodynamic Model

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Bay of FundyBay of Fundy

Nova Scotia

Maine

Relate ISLW to Existing Chart Datum

Determine Multiplier at Local Tide Stations

Datum = Multiplier * ISLW

Indian Spring Low Water• Suggested by Sir

George Darwin for Indian Waters

• ISLW = MSL – (M2+S2+K1+O1)

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S2M2

K1O1

ISLW Datum

Saint Andrews

M2 2.722

S2 0.406

K1 0.158

O1 0.114

Sum 3.400

Zo 3.871

Multiplier 1.14Great Britain Hydrographic Office (1969). “Tides and Tidal Streams.” Chapter Two in Admiralty Manual of Hydrographic Surveying, Vol. 2, Somerset, England, 118pp.

Datum = F*S where,

• If (S < 2 m) F = 0.85 • If (S > 5 m) F= 1.0 • Else F is linearly

interpolated between the above values.

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S2M2K1

O1 N2

Hannah, DFO• S =

M2+N2+S2+K1+O1

Datum

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RMS = 0.22 m RMS = 0.30 m

38 CHS Tide Stations

Tidal Power Stations Perform Repeat Surveys

Prior to Installation to Observe Existing Sediment Transport

15http://www.rgu.ac.uk/research/innovation/page.cfm?pge=7560

Deer Island

Campobello

Island

Eastport

Passamaquoddy Bay

Provides a Smooth Sounding Datum Throughout the Model

Uniform Transitions Between Datasets

Datum Based on Varying Predicted Tides Throughout the Region

Resolve Tides from Hydrodynamic Model + Non Tidal Residuals

Sounding Datum based on Hydrodynamic Model

Resolve Tides from Hydrodynamic Model + Non Tidal Residuals

Sounding Datum based on Hydrodynamic Model

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Ian Church

18

Day 1 = BlackDay 2 = Red

Hydrodynamic

ModelTide

Black’s Harbour

Tide

Wilsons Beach Tide

St. Andrew’s Tide

Eastport Tide

Fairhaven Tide

Separation 30cm 80cm 90cm 2cm 35cm 40cm

Multibeam Sonar Swath