1. Departamento de Física
Coupled Ocean-Atmosphere model for Regional Climate studies in the Mediterranean Sea
William Cabos
Departamento de Física
Universidad de Alcalá
European ROMS Workshop 6-8 November

2. Coupling of REMO to ROMS
The aim of our project
Regionalization of Climate change projections of IPCC 4th AR models for the Iberian Peninsula
Tool
Regional coupled Ocean–Atmosphere Model
Atmospheric component
REMO (Regional Model)
Ocean component
ROMS (Regional Ocean Model System)
Coupler
OASIS3 coupler
Each of these components has been successfully used for a wide range of climate studies.

3. avoid inconsistences between global and regional models
Advantages of nested climate models
Regional simulations of high resolution consistent with global circulation when resources are limited
avoid inconsistences between global and regional models
reduce the effects of grid size changes from global to region of interest
Global model
Intermediate nested model
Region of interest

4. Model Setup Model domain: Atlantic Ocean, Mediterranean and Black Sea
Mediterranean circulation is poorly simulated in global models

5. Model Setup Conditions to take into account in the model
It should simulate the Mediterranean present time climate and climate change projections
The Atlantic ocean is necessary for the global climate signal
The ocean and the atmosphere should have the same grid:
no interpolation
1 hour exchange frecuency
The masks should be as like as possible
The Black Sea should be included

6. COUPLED MODEL
Atmosphere
REMO
Coupler
OASIS
Ocean
ROMS

7. REMO (REgional MOdel) Atmospheric General Circulation Climate Model.
developed in the Max Planck institute of Metereology
Hidrostatic
- maximal grid resolution: 1/10 degree.
This grid resolution enables the model to resolve the most important topographic features
Sofisticated vegetation scheme
State of the art soil, hydrographic and glaciar models
Widely used for climatic and impact studies in Europe
Echam4 physics
Rotated coordinates

8. REMO Validation : Temperature
REMO and CRU temperature: South Spain
REMO and CRU temperature differences
Different regions

9. REMO Validation : Precipitation
All Spain
Central Spain
North Spain

10. REMO coupled model domain

11. REMO coupled model setup

12. OASIS Flexible, modular, well supported
Sinchronization of component models
Coupling fields exchange: arbitrary number, frecuency
I/O actions
Interpolation
PSMILe communication: MPI, direct communication between models with the same grid and partition.

13. ROMS Roms-Agrif version 0.22 degrees resolution 30 leves, qs=6.0 qb=0.
Open boundaries: restoring to global coupled model data
Rotated coordinates:
Topography and ocean forcing fields are rotated with Eulerian angles, f calculated in geogrphical coordinates
GDEM3 initial conditions
Spinup with REMO climatology : winds, heat and fresh water fluxes

14. ROMS

15. ROMS: spinup forcing
REMO wind stress:
February
REMO wind stress:
July

16. ROMS: spinup forcing
REMO Heat Flux:
February
REMO Heat Flux:
July

17. ROMS without nudging

18. ROMS Black Sea with nudging (.11 degrees)

19. ROMS .22 with nudging

20. ROMS .22 with nudging

21. Finish the coupling interface Fix the bosphorous problem
Future work
Finish the coupling interface
Fix the bosphorous problem
Use 6-hour REMO data for spinup
Include tides
Validate ROMS
-experiments with the coupled model

22. REMO

23. REMO

24. Nested models
A hierarchy of nested models with growing resolution allows:
Regional simulations of high resolution consistent with global circulation when resources are limited
To avoid inconsistences between the global model and the regional model in the region of interest
To reduce the impact of grid size difference
Global model
Intermediate nested model
Region of interest

25. OASIS
Well structured routines, allows model exchange

26. REMO

27. REMO

28. REMO

29. REMO

30. REMO

31. ROMS: downscaling of SODA data

32. REMO

33. Activities of our group related to ROMS
Regional Studies: Climate change and present climate validation:
Present climate:
Climate change: different scenarios:
Global data:
IPCC 4th AR ocean-atmosphere models
Regional models:
Ocean – ROMS; forced with global and regional atmosphere
Atmosphere – REMO
Coupling necessary for local effects

34. REMO

35. ROMS: downscaling of SODA data
Ocean reanalysis: conbines observations with ocean data
from 1958 to present
.5 degree resolution
Does not show the most important features of Mediterranean circulation : resolution ?
ROMS
.12 degrees simulation with SODA boundary data
Can be used for higher resolution local climate studies
Weak nudging to SODA data?