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 Garcia
Department of Earth and Atmospheric Sciences
University of Alberta
Model Configuration
ANHA12
Model : NEMO 3.4
LIM2 + EVP
Resolution : 1/12 degree
Mesh : 1632 x 2400
50 levels
LS : ~ 5 km
CAA : ~ 4 km
km
ANHA: Arctic and Northern Hemisphere Atlantic
Experiment Setup
Initialization:
3D T, S, U and V (GLORYS1v1,
Sea Ice
Jan02)
Atmospheric forcing (CGRF, hourly):
T2, Q2, U10, V10
Precipitation
Radiation (SW & LW)
Snow: CORE2 (IA)
Runoff: Dai and Trenberth climatology
OBC:
U, V, T and S (GLORYS1v1)
NO temperature & salinity restoring
Jan 2002 – 2008 -- > 2010
CGRF: CMC GDPS reforecasts
GDPS: Global Deterministic Prediction System
CMC: Canadian Meteorological Centre
GLORYS: GLobal Ocean ReanalYses and Simulations
Labrador Sea in ANHA12
Sea Ice
Concentr
ation
Sea Ice
Thickness
Mixed
Layer
Depth
Velocity
magnitude
averaged
over top
55 m
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 Update
Dai and Trenberth 1o x 1o gridded data
Distribute gridded runoff
into “coast-buffer-zones”
volume
conserved
salinity changes in top 50m
MLD
changes
Planned RUNs
solid line: finished runs
dash/dotted: planned simulation/re-run with updated data
orange text: finished or expected finish time
time 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
ANHA4: ¼° resolution (parent)
A
X:724
AGRIF
1/12°
Y:874
Y:290
X:240
AGRIF
1/12°
Y:544
Y:180
0.25
0.20
0.15
0.10
0.05
0.00
X:814
X:270
Ice velocity [m/s]
Transformation
(1:3 Horiz. ratio)
1/12° AGRIF
Grid
Boxes
Ice Thickness [m]
AGRIF
1/12°
Control
Grid Box
1/4°
1/4°
•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
B
5
4
3
2
1
0
1Debreu,
Laurent, Christophe Vouland, and Eric Blayo. "AGRIF:
Adaptive grid refinement in Fortran." Computers & Geosciences 34.1
(2008): 8-13.
4/7/2015
Effect of enhanced melt from
Greenland Ice sheet?
Warming of our climate is
melting Greenland glaciers
Sea level rise
17
Greenland
ice sheet
mass loss
trend 20032008
Deep convection
in the Labrador
Sea
(237km3/yr)
Increase freshwater input in Baffin Bay
Experiments 1 to 9:
Exp. 1 Control run
Hydrography?
Circulation?
Exchanges?
Feedbacks?
Exp. 2- 9 enhance melt from
west Greenland, between 158- 1580
km3/yr
Fury and Hecla Strait
Freshwater Pathways into the North Atlantic
from the Canadian Arctic Archipelago and the
Greenland Ice Sheet
ANHA 1/12⁰ Configuration
• 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
Holloway and Proshutinsky 2007
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
Probabilities from forward trajectories, run at 1/4 ⁰ resolution, initiated at Helheim Glacier
Laura C. Gillard and Paul G. Myers
Department of Earth and Atmospheric Sciences
University of Alberta