An OGCM with Movable Land- Sea Boundaries w/Application to Cook Inlet L. Oey, T. Ezer & M. Johnson...
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Transcript of An OGCM with Movable Land- Sea Boundaries w/Application to Cook Inlet L. Oey, T. Ezer & M. Johnson...
An OGCM with Movable Land-Sea Boundariesw/Application to Cook Inlet
L. Oey, T. Ezer & M. JohnsonPrinceton Univ. & Univ. Alaska
Goal: A Wetting & Drying (WAD)
scheme that works w/OGCM’s such as the Princeton Ocean
Model (POM)p.2
p.3
p.4
Method: Solve Full 3-D PE (include everything), and impose conditions –
1. WETMASK = 0 for D Hdry,= 1 otherwise.
2. if (Di,j+Di-1,j)/2 Hdry
3. if WETMASKij*WETMASKi-1,j = 0
, 0i jU ,i j
ijkU U
p.5
One-Dimensional WAD Dynamics0 = +
xDU
tD
2+ =
UD U D D H rgD UD
t x x x D
Min , 1r rlD UD
(1a)
(1b)
Condition for friction to dominate is:
Then LHS of (1b) can be dropped, and (1a) & (1b) give:
Typical values: r 10-4~10-3 m/s (in POM, and also Balzano, 1998), 10-4 s-1 (e.g. M2 tide), D = O(1) m, | |U = O(1) m s-1, and l 100’s km for tides.
(2)
(3)2 2
2
22+ = xgDH gD H
r r x
gDD D Dt x x r x
“Advection Velocity”
“Diffusivity” “Sink” if Convex “Source if Concave
Note the possibility of a “breaking-wave” solution
The diffusive penetration distance, Lpd say, at a given time t is proportional to D(g/r)1/2. p.6
A Challenging
(Giant) Water-Fall Problem:
p.7
p.8
Tsunami:
Energy Considerations:
2
1
2 2 2
0
( )lo x
ox
g Bdx B g Du dx
22 2 2
( )2 o
oBDu
g B x
therefore,
Since
and /10m u 14m s
At land-fall,
p.9
Cook Inlet Alaska
p.10
Large Tidal Range Inland
Weak Tides Offshore
p.11
Model of Cook Inlet, Alaska
p.12
Flood Begins @ Upper Inlet
Forcing:
12-hr tide
Rivers
Wind: Anchorage
Nikiski
Drift Riv.
Augustine Is.
p.13
Wetting & Drying:
p.14
Low Tide, River = 0 (i.e. ~ winter)
Anchorage
Skiing
Portage Galcier
1st Picture
Turnagain Arm
Knik Arm
p.15
p.16
Salinity sections in upper CI at low &
high tide
A
B
C
A
B
C
p.17
Salinity & rip tides in central CI
I=140
I=180
Kal
iforn
sky
Bea
ch
1 hr before high tide
p.18
Vertical VelocityW-Contours
Effects of River-Induced Buoyancy on rip tides
w/River Discharge
No River: Climatology only
Homogeneous Water
p.19
ConclusionsAn OGCM with dynamic (movable) land-sea
boundaries has been developed
The model conserves mass & energy and has been tested for idealized and analytical solutions as well as realistic conditions in the Cook Inlet wherein forcing such as tides, winds, rivers were specified
Oey, 2005: A WAD Scheme for POM. Ocean Modelling, 9, 133-150.Oey, 2006: An OGCM w/Movable Land-Sea Boundaries, Ocean
Modelling, in press
Financial supports from MMS, and computing supports from GFDL are gratefully acknowledged. p.20