Download PPT - Regional Ocean Modeling System

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
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.
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
Model Setup
Model domain: Atlantic Ocean, Mediterranean and Black Sea
Mediterranean circulation is poorly simulated in global models
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
COUPLED MODEL
Atmosphere
REMO
Coupler
OASIS
Ocean
ROMS
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
REMO Validation : Temperature
REMO and CRU temperature: South Spain
REMO and CRU temperature differences
Different regions
REMO Validation : Precipitation
All Spain
North Spain
Central Spain
REMO coupled model domain
REMO coupled model setup
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.
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 1958-2001 climatology : winds, heat
and fresh water fluxes
ROMS
ROMS: spinup forcing
REMO wind stress:
February
REMO wind stress:
July
ROMS: spinup forcing
REMO Heat Flux:
February
REMO Heat Flux:
July
ROMS without nudging
ROMS Black Sea with nudging (.11 degrees)
ROMS .22 with nudging
ROMS .22 with nudging
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
REMO
REMO
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
OASIS
Well structured routines, allows model exchange
REMO
REMO
REMO
REMO
REMO
ROMS: downscaling of SODA data
REMO
Activities of our group related to ROMS
Regional Studies: Climate change and present climate
validation:
Present climate: 1958 - 2001
Climate change: different scenarios:2000 - 2100
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
REMO
ROMS: downscaling of SODA data
SODA
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?