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

aaa

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

aaa

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

600

800

100

0

-47.4-47.2-47.0-46.846.5

47.0

47.5

48.0

200

400

600

800

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