Section 3.4

The Impact of IPCC Scenarios

We use the simulation results generated using the IPSL "Earth system model"
(Braconnot, et al, 2006) for external forcing fields at the ocean surface.
The IPSL-CM4 version of the model couples four components of the Earth system.
LMDZ is the component for atmospheric dynamics and physics. 
ORCA is the component for ocean dynamics. LIM is the component for sea-ice dynamics
and thermodynamics. ORCHIDEE handles the land surface.

The atmospheric parameters needed to force the ORCA2_LIM_PISCES configuration of 
the NEMO at the ocean surface are described in Sec xxx.
## zonal and meridional wind components at 10m above the surface, 
## temperature and specific humidity at 2m above the surface,
## snow falling and precipitation rates, downwelling shortwave and longwave at the surface.
Daily and monthly values of the parameters are avaialble for the following simulations 
on a 96 x 71 longitude-latitude grid. All simulations are started with the same procedure. 
The ocean starts from rest with temperature and salinity set to the values of 
the Levitus (1982) atlas. The sea-ice characteristics correspond to a ten years adjustment 
of the sea-ice model from a forced ocean-ice simulation. The atmosphere is initialized from 
the ECMWF (ERA15) for 1979, January 1st. For more details, see Braconnot, et al. 2006.
With this procedure, the first ten years of the simulation correspond to rapid adjustments 
between all the models, and they are not representative of the longer time scale evolution
of the simulation.

"2L20" is a control simulation with concentration of the different trace gazes
prescribed to modern trace gazes concentration (the period 1840-2409).

"2L24" is a pre-industrial simulation with trace gazes concentration
prescribed to pre-industrial values (circa 1750) (1931-2080).

"2L23" is a CMIP simulation with 1% increase in the CO2 concentration
until quadrupling CO2 is reached (1931-2080).

"2L23B" is an additional stabilization scenarios with 2xCO2 
starting from the CMIP run when the corresponding level of CO2 is reached (1931-2080).

"2L26" and "2L27" are Scenarios A2 and A1B respectively for 2000-2100.

"2L28" and "2L31" are Scenarios B1 for 2000-2100.

The full set of IPCC simulations performed at IPSL are described 
at http://mc2.ipsl.jussieu.fr/simules.html.

EXP 1: Reference run

We'll use "2L24" surface forcing datasets to run the ORCA2_LIM_PISCES 
from 1850 to 2409 to generate a control simulation of biogeochemical parameters
for that period. For inital state of the model at the beginning of the simulation
(01Jan1850), we'll use several spinup results from various lenghts of the integration perids
with the CFS4.1 CORE bulk formula forcing as well as the climatorolgy CLIO bulk formula forcing. 
to see whether any differences are detected in the simulated biogeochemical parameters.

EXP 2: A2 sceanrio

Using "2L26" datastes, we'll run the ORCA2_LIM_PISCES for the period 2010 to 2100.
For the initial condition, the restart conditions at the end of 2009 in the EXP 1 will be used.

EXP 3: 1xCO2 2xCO2 sceanrio ???
"2L23", "2L23B"