Hernan G. Arango

1
Atmospheric-Ocean Forecast Experiments in the
New Jersey Coastal Zone
by Hernan G. Arango Hai Pan, Scott M.
Glenn, Michael Crowley, Dale B. Haidvogel, Roni
Avissar Institute of Marine and Coastal Sciences
Center for Environmental Prediction Rutgers
University New Brunswick, NJ January 27, 1999
2
Outline

• Coupled atmosphere-ocean modeling system
• Forecast cycles and ensemble
• Sensitivities to initialization and atmospheric
  forcing
• Analysis of 1999 upwelling event

3
meters
ROMS Bathymetry
4
meters
ROMS Bathymetry
5
meters
Node A
ROMS Bathymetry
6

• 
  Initialization
• Continuous initialization from previous
  forecasting cycle ensemble
• MODAS (Bob Rhodes and Dan Fox, NRL).

7

• 
  Initialization
• Continuous initialization from previous
  forecasting cycle ensemble
• MODAS (Bob Rhodes and Dan Fox, NRL).

• 
  Forcing
• RAMS surface winds and fluxes every half-hour
• NOGAPS/COAMPS surface winds and fluxes every
  twelve hours
• One-way coupling via atmospheric boundary layer
• Wind-induced waves from WAM and LEO-15 node
• Zero fresh water flux (E-P)
• No Tides

8
Navy Products
NOAA Rutgers
Global Atmospheric Forecasts
NOGAPS
NCEP
I.C. B.C.
I.C. B.C.
Local Atmospheric Forecasts
COAMPS 27 km 6 hours
RAMS 4 km 30 min
Atm. Forcing
Atm. Forcing
Ocean Models
ROMS
PBL SBL BBL WBL
MODAS (POM)
I.C.
Waves
WAM
Wave Models
9
Boundary Layer Schematic
L o n g w a v e
Shortwave
O
E v a p
H
H
10

• 
  Initialization
• Continuous initialization from previous
  forecasting cycle ensemble
• MODAS

• 
  Forcing
• RAMS surface winds and fluxes every half-hour
• NOGAPS/COAMPS surface winds and fluxes every
  twelve hours
• One-way coupling via atmospheric boundary layer
• Wind-induced waves from LEO-15 node
• Zero fresh water flux (E-P)
• No Tides

• 
  Assimilation
• Melding of SST and hydrography (OI) once a day
• Surface currents from CODAR (nudging)

11

• Ocean-Atmosphere
• Forecasting Cycles

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Forecast Cycle - July, 1999
Sun. Mon. Tues. Wed.
Thur. Fri. Sat.
4 5 6
7 8
9 10
Day 1 Forecast Day 2 Forecast Day 3
Remote Sensing / Node Data
Remote Sensing / Node Data
Model Run
Day -2 Day -1 Nwcst Day 0
Assim Day -3 Day -2
Day -1
11 12 13
14 15 16
17
18 19 20
21 22 23
24
25 26 27
28 29 30
31
Day 1 Forecast Day 2 Forecast Day 3
D4
Forecast Day 4
Day 1 Forecast Day 2 Forecast Day 3
Remote Sensing / Node Data
Remote Sensing / Node Data
Rmt / Node
Model Run
Model Run
Ship/AUV Data
Ship/AUV Data
Nwcst day 0 Day -2
Day -1 Nwcst Day 0
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• Sensitivity to
• Initialization and Forcing

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July 1999 - Tuckerton Winds
15
July 14, 1999 - 1500 GMT Temperature Cross
Sections
25 23 21 19 17 15 13 11
0 5 10 15 20 25
Temp (oC)
Depth (m)
Observations
0 5 10
15 20
Distance (km)
25 23 21 19 17 15 13 11
25 23 21 19 17 15 13 11
0 5 10 15 20 25
0 5 10 15 20 25
Depth (m)
Depth (m)
Temp (oC)
Temp (oC)
RAMS Forcing
COAMPS Forcing
0 5 10
15 20
0 5 10
15 20
Distance (km)
Distance (km)
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AVHRR SST July 28, 1999 0800 GMT
COAMPS Forcing July 28, 1999 2100 GMT
28 26 24 22 20 18 16 14 12 10
3942N
3940N
3930N
3930N
3920N
3918N
3910N
7424W 7412W 7400W
7348W
7420W 7410W 7400W
7350W
Surface Currents and Temperature (oC)
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AVHRR SST July 28, 1999 0800 GMT
28 26 24 22 20 18 16 14 12 10
MODAS/RAMS Forcing July 28, 1999 2100 GMT
3942N
3940N
3930N
3930N
3920N
3918N
3910N
7424W 7412W 7400W
7348W
7420W 7410W 7400W
7350W
Surface Currents and Temperature (oC)
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AVHRR SST July 28, 1999 0800 GMT
28 26 24 22 20 18 16 14 12 10
RAMS Forcing July 28, 1999 2100 GMT
3940N
3940N
3930N
3930N
3920N
3920N
3910N
3910N
7420W 7410W 7400W
7350W
7420W 7410W 7400W
7350W
Surface Currents and Temperature (oC)
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Upper Layer Along Shore, Time-integrated
Transport (July, 1999)
104m2
20
Bottom Layer Along Shore, Time-integrated
Transport (July, 1999)
104m2
21
Cross-Shelf Time Integrated Transport
Ekman Pumping (m/day)
20 15 10 5 0 -5
Utop Ubot Tauy
offshore
104 m2
3942N
onshore
26 27
28 29
30 31
3930N
Along-Shelf Time Integrated Transport
25 15 5 -5
Vtop Vbot Taux
North
3918N
104 m2
7424W 7412W 7400W 7348W
South
July 28, 1999
26 27
28 29
30 31
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Conclusions

• Initial conditions generated by continuous
  assimilation of CODAR produce better forecasts
  than cold starts using MODAS without CODAR
  assimilation.
• High spatial and temporal resolution RAMS
  produced better ocean forecasts than courser
  COAMPS forcing.
• Offshore of the the upwelling center
• Forecasts indicate the upper layer offshore
  transport exceeds
• the Ekman transport.
• The bottom layer onshore transport does not fully
  compensate.
• Upwelling flow is 3-D with cold bottom water
  flowing in from
• the North.
• There is a need for a coupled, high-resolution
  ocean-atmosphere system that can be run locally
  in forecast mode.

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Future System Improvements

• Estuaries
• River runoff (Signell Hetland).
• Tides (Bogden Chant).
• ESSE assimilation (Lermusiaux).
• Coupled bio-optical model (EcomSim - Bisset).
• Sediment resuspension and transport
  (Styles Glenn).

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R.U. C.O.O.L.
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R.U. C.O.O.L.