PERD CCIES POL:Current & Temperature Changes along the
Newfoundland and Scotian Shelf/Slope
Focus:
Potential occurrence and impacts of climate changes in ocean currents, transports and temperatures in Atlantic offshore oil and gas production and exploration areas
Components:·Observational studies of Labrador Current in key areas
·Regional ocean circulation models
·Implications of climate-change scenarios for regional circulation and impacts
Participants:-Loder, Hannah, Dupont, Geshelin, Yashayaev, Wright et al. (BIO, DFO)
-Han, Colbourne et al. (NAFC, DFO)
Linkages:-Coordination with OEF POL (1.2.1) and industry co-sponsorships for moored measurements
-North Atlantic circulation modelling (BIO/Dalhousie)
-DFO Atlantic Zonal Monitoring Program (AZMP)
-NW Atlantic ocean climate studies (BIO et al.)
Current and Temperature Changes along the
Newfoundland/Scotian Shelf/Slope
•PERD Climate Change Impacts on the Energy Sector (CCIES) POL 6.1.1
•Coordination with PERD Offshore Environmental Factors POL 1.2.1
•Oil and Gas Industry Partnerships in Observational Components
Oil & Gas Exploration and Production on the Scotian Shelf and Slope
• Labrador Current extension along shelf edge
• Proximity to energetic Gulf Stream
Oil & Gas Exploration and Production on the Grand Bank and in Flemish Pass
• Severe ocean conditions
• Iceberg alley (Labrador Current) along shelf edge
• Persistent Labrador Current in deep-water frontier blocks
CCGV Hudson at Hibernia
Mean Transports in NW Atlantic
• Shelf/Slope Labrador Current part of a larger-scale coastal current
• Large diminution in transport in Grand Bank region
• Past and potential future variations in equatorward extent of Labrador Current
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30
60o
50o
40o
80o 70o 60o 50o 40o
80o 70o 60o 50o 40o
60o
50o
40o
0.80.9
4.2
3.3
6.7
0.8
1.3
5.8
30
Irminger
21
5
0.4
0.1
0.50.3
0.03
0.2
0.40.3
0.2-0.05 3.2
NADW /LSW
GulfStream
0.7
0.7
NADW /NABW
150
17
ANNUAL MEAN
TRANSPORT (Sv) DeepLabradorCurrent
NW AtlanticCoastal Current
Mean Transports in Grand Bank Region
• Flow bifurcations north of Flemish Pass, at Tail of Bank, and in Laurentian Channel
• Variability important to downstream regions
aa
60o
50o
40o
80o 70o 60o 50o 40o
80o 70o 60o 50o 40o
60o
50o
40o
0.80.9
4.2
3.3
6.7
0.8
1.3
5.8
30
Irminger
21
5
0.4
0.1
0.50.3
0.03
0.2
0.40.3
0.2-0.05 3.2
NADW /LSW
GulfStream
0.7
0.7
NADW /NABW
150
17
30
Freshwater Transports in NW Atlantic
• Freshwater and ice from subarctic important to shelf/slope and deep-ocean dynamics in North Atlantic
• Sea ice and icebergs important to transportation and oil and gas activities
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FreshwaterTransports
(mSv)
Shelf / Slope Front
Gulf Stream North Wall
60o
50o
40o
80o 70o 60o 50o 40o
80o 70o 60o 50o 40o
60o
50o
40o
29
1.6
117
29
35
5.7
179
10
9
127
40-1.8
50
13
13
32
0.9
2.6
10
1.5
3
5.0
3
1.40.7
1.4
16
MEDIANSEA-ICEEXTENT
WATER ICE
26
Observational Program Elements 1
Multi-Year Cross-Slope Arrays of Moorings at Key Sites on AZMP lines on:
Scotian Slope (Halifax line)
Newfoundland Slope (Flemish Pass line)
Current and hydrographic (T, S) time series
PERD OEF: high-frequency and extreme currents
Industry funding from 7 oil companies
Moored Array for Current & Hydrographic Observations on Scotian Slope
• Current-meter moorings to describe variability in cross-slope structure over 2 years
• Cooperative with PERD OEF and 7 oil companies
Variability in Seasonal Along-Slope Flow from 2000-02 Moored Measurements
• SWward flow at all depths at 1100- and 2000-m sites until winter 2002
• NEward flow in upper 500m at all 3 sites in spring-summer 2002
• Seasonal + Interannual variability
Observational Program Elements 2
Satellite Altimetric Data (1992- )Broad-scale surface current patterns & anomalies
Integration with other datasets
Potential for currents/transport monitoring ?
Historical DataCurrents: Moorings, Drifters
Hydrographic (1950- ): T, S, Geostrophic
Coastal Sea Level
Variability in Surface Currents from Satellite Altimetry (Han)
• Averaged seasonal changes over 1992-2000 from TOPEX/Poseidon
• Interannual variations also under investigation
Historical Current Stats in Flemish Pass
• Means and standard deviations shown by season and depth
• Limited coverage of seasonal variability and deep water
• Mean (Labrador Current) generally exceeds fluctuations
-47.4-47.2-47.0-46.846.5
47.0
47.5
48.0
200
400
600
800
100
0
-47.4-47.2-47.0-46.846.5
47.0
47.5
48.0
200
400
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800
100
0
-47.4-47.2-47.0-46.846.5
47.0
47.5
48.0
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100
0
Observed Deep-Water Currents in Flemish Pass:Means & SDs
20 cm s-1
Apr - Aug Jul - Oct Oct - Feb
Upper layer (z < 200 m) Lower layer (z > 500 m)Mid layer
(200 m < z < 500 m)
PERD/Industry Current Meter Moorings in Flemish Pass: 2002-04
Sites and Model Summer Currents
• Site A (400m): Core of Labrador Current
• Site B (1100m): Deep• Jun-Nov 2002: Recovered• Nov02 - Jul03: Deployed• Jul03 - Spr04: Proposed• Support from EnCana,
ChevronTexaco & Petro-Canada
Seasonal-Mean Currents in 2002
• Climatological seasonal currents from model (contours) (Xu)
• 2002 seasonal currents from moorings: summer, fall
Hydrography and Geostrophic Velocity in Flemish Pass: June 2002
Geostrophic Velocity + Bottom Velocity from Climatological Model: June 2002
Seasonal Surface Currents from Altimetry
• Seasonal surface current anomalies from TOPEX/Poseidon (1992-2000), added to LA POP model mean flow
• Persistent features of Labrador and North Atlantic Currents
Surface Current Variability from Altimetry
• Time variability of currents at cross-over point of TOPEX / POSEIDON tracks
• Plans to compare with geostrophic and moored measurements, and models
Regional Ocean Circulation Modelling
Evaluations of 1985-1998 Simulation from Los Alamos Ocean General Circulation Model (POP) (Smith et al.)Realistic wind stress but restoration to T, S
climatology at boundaries
High spatial (0.1o) resolution: quasi-realistic Gulf Stream and eddies
Volume, T and S budgets for Slope Water region
Comparisons of temporal variability with observations
Regional Ocean Circulation Modelling 2
Evaluations of Hindcast Simulations with Dalhousie/BIO OGCM (modified POP) (planned with Wright et al.)Realistic surface forcing and improved
interior relaxation from climatology
Intermediate spatial (0.3o) resolution but plans to reduce
Focus on variability in Labrador Current extension and Slope Water
Regional Ocean Circulation Modelling 3
• Variability and Sensitivity Studies with Regional Model for Newfoundland Shelf (FEM) (planned with Han)
Input from larger-scale model for response to extreme wind forcing in 1990s
Implications of Climate-Change Scenarios Implications for current, transport,
hydrographic (and ice) variability on Newfoundland and Scotian Shelf/Slope
Labrador Current and Gulf Stream influences
Impacts on shelf-edge production facilities
Impacts on deeper-water (slope) developments
To DateLiterature review
Description and understanding of observed variability
Information transfers to industry
Implications of Climate-Change Scenarios
Refined strategy for 03/04Focus on identification of: forcing-response
relations from climate variability studies and potential impacts of climate-change scenarios
Defer regional model simulations for climate change until improved larger-scale models
Prepare report on recent and potential oceanic changes relevant to climate-change impacts assessment for Atlantic oil and gas production areas
Summary Points Moored measurement arrays, plus hydrographic
sections and altimetry, providing improved estimates of Labrador Current variability (seasonal, interannual ?) at key sites
Mounting observational support for seasonality and interannual variability in Labrador Current extension beyond Grand Bank, but poorly understood
Improved capability for describing interaction of Labrador Current and Gulf Stream, but remains poorly understood
Summary Points 2 Importance of variable atmospheric forcing, ice,
freshwater and ocean dynamics
Reliable predictive model for seasonal and interannual variability of Labrador Current not yet available
Assessment of implications of climate change for Atlantic offshore can draw on knowledge of past variability while predictive capability being improved