NEMO Modelling

NSERC – CCAR Projects

• VITALS• Geotraces

Photo courtesy Department of Fisheries and Oceans

Paul G. Myers, Xianmin Hu, Amber M. Holdsworth, Clark Pennelly, Laura Castro de la Guardia, Laura Gillard, Jingfan Sun, Margaret Campbell, Peggy Courtois, Nathan Grivault, Yarisbel GarciaDepartment of Earth and Atmospheric SciencesUniversity of Alberta

Model ConfigurationModel Configuration

km

ANHA: Arctic and Northern Hemisphere Atlantic

ANHA12

Model : NEMO 3.4 LIM2 + EVP

Mesh : 1632 x 2400 50 levels

Resolution : 1/12 degree

LS : ~ 5 km

CAA : ~ 4 km

Experiment SetupExperiment Setup

Initialization:

Atmospheric forcing (CGRF, hourly):

NO temperature & salinity restoring

Jan 2002 – 2008 -- > 2010

3D T, S, U and V (GLORYS1v1, Jan02)

Sea Ice

Snow: CORE2 (IA)

Runoff: Dai and Trenberth climatology

T2, Q2, U10, V10 Precipitation Radiation (SW & LW)

CGRF: CMC GDPS reforecasts CMC: Canadian Meteorological Centre

GDPS: Global Deterministic Prediction System GLORYS: GLobal Ocean ReanalYses and Simulations

OBC: U, V, T and S (GLORYS1v1)

Labrador Sea in ANHA12

Sea Ice Concentration

Velocity magnitude averaged over top 55 m

Mixed Layer Depth

Sea Ice Thickness

Also: animations (2003-2008) at http://knossos.eas.ualberta.ca/myers/NEMO.html

CAA in ANHA12

Sea Ice Concentration

Sea Ice Thickness

Also: animations (2003-2008) at http://knossos.eas.ualberta.ca/myers/NEMO.html

West Lancaster Sound Fluxes

GLORYS 2v3 vs GLORYS1v1(volume flux through Bering Strait and Lancaster Sound)

NEMO Updates

Compute snow fall from total precipitation based on 2-m air temperature

Fixed a discontinuity “line” in wind stress field

Update runoff with a new interpolation approach

CICE with NEMO3.4 (workable but not tested for long simulation)

NEMO Updates

compute snow fall from total precipitation based on 2-m air temperature

fixed a discontinuity “line” in wind stress field

update runoff with a new interpolation approach

CICE with NEMO3.4 (workable but not tested for long simulation)

RUNOFF UpdateDai and Trenberth 1o x 1o gridded data

Distribute gridded runoff

into “coast-buffer-zones”

volume volume conservedconserved

salinity changes in top 50m

MLD

changes

Planned RUNs

solid line: finished runsdash/dotted: planned simulation/re-run with updated dataorange text: finished or expected finish timetime schedule for simulation with CGRF after 2010 is still not known

Sea Ice Model Comparison

Select Ice Thickness Validation

Accumulated Winter Thermodynamic & Dynamic Ice Thickness Change

unit: m

AGRIF: Adaptive Grid Refinement In Fortran1

X:240

Y:29

0

X:724

Y:87

4

AGRIF0.25

0.20

0.15

0.10

0.05

0.00

5

4

3

2

1

0

A

B

1Debreu, Laurent, Christophe Vouland, and Eric Blayo. "AGRIF: Adaptive grid refinement in Fortran." Computers & Geosciences 34.1 (2008): 8-13.

1/12°

AGRIF

Transformation(1:3 Horiz. ratio)

ControlGrid Box

1/4°1/12°

1/12

°

1/4°

AGRIF1/12°

X:814

Y:54

4

ANHA4: ¼° resolution (parent)

•High resolution nest: better resolving skill•Simulation runs alongside parent•AGRIF forced by separate set of data•AGRIF boundaries supplied by parent•Computational expense: 2-4 X

Ice

velo

city

[m/s

]Ic

e Th

ickn

ess

[m]

AGRIF Grid Boxes

X:270

Y:18

0

04/18/23

Effect of enhanced melt from Greenland Ice sheet?

Warming of our climate is melting Greenland glaciers

Deep convection in the Labrador

Sea

Sea level rise

Increase freshwater input in Baffin Bay

Feedbacks?Hydrography? Circulation?Exchanges?

Greenland ice sheet mass loss trend 2003-2008

(237km3/yr)

Experiments 1 to 9:Exp. 1 Control run

Exp. 2- 9 enhance melt from west Greenland, between 158- 1580 km3/yr

17

Freshwater Pathways into the North Atlantic from the Canadian

Arctic Archipelago and the Greenland Ice Sheet

• Understand pathways of freshwater into the North Atlantic Ocean

• Fluxes through Fury and Hecla Strait • Relative role compared to other gateways through the

Canadian Arctic Archipelago. • Pathways for the freshwater discharged from major

tidewater glaciers around Greenland• Function of time and glacier location

• Pathways of Irminger Water to coastal Greenland

Laura C. Gillard and Paul G. MyersDepartment of Earth and Atmospheric Sciences

University of Alberta

Holloway and Proshutinsky 2007

ANHA 1/12⁰ Configuration

All questions will be examined by using output from a suite of ocean general circulation models (NEMO) at 1/4 ⁰ and 1/12⁰, as well as Lagrangian particle tracking tool for trajectory analysis

Fury and Hecla Strait

Probabilities from forward trajectories, run at 1/4 ⁰ resolution, initiated at Helheim Glacier