Marine Ecosystems Research Department - jamstec japan agency ...

Japan Marine Science and Technology Center
Frontier Research System for Global Change
of all feedbacks combined, using the top-of-the atmosphere
fluxes of solar and terrestrial radiation obtained
from the Earth Radiation Budget Experiment (ERBE).
Our analysis indicates that the feedbacks as a whole
are positive, and are responsible for reducing the
radiative damping of global surface temperature
anomaly by as much as %. It also reveals that this
positive feedback effect is attributable to both long
wave and solar components.
Similar feedback analysis is conducted for three
GCMs. It is noted that the sign and magnitude of the
net feedback effect in all three models is similar to
those of the observed. However, the contributions
from the terrestrial and solar components of the net
feedback effect are different between the simulated
and observed. It is indicated that the difference in each
components of the feedback is attributable mainly to
the failure of the models to simulate the terrestrial and
solar components of the cloud feedback.
b. Carbon Cycle Research Group
During the last few years, the Carbon Cycle
Research Group engaged in the development of an
ecosystem model, NEMURO (North pacific
Ecosystem Model Used for Regional Oceanography),
in the North Pacific Marine Science Organization
(PICES). The study using NEMURO has contributed
as a part of the North Pacific Task Team (NPTT) in
the Joint Global Ocean Flux Study (JGOFS). In
FY, a D ecosystem model was developed. The
simulated global distributions of chlorophyll, concentrations
of nutrients and partial pressure of CO agree
roughly with observations. A case study shows that
the seasonal vertical migration of copepods affects primary
production in the northwestern Pacific, and that
the presence of copepods throughout the year reduces
the primary production by diatoms. The globally averaged
total downward flux by the vertical migration of
copepods is estimated to be .GtC/yr, which is -
% of that by settling particle at the depth of m.
Therefore, this process would be required for realistic
simulation of the marine biological cycles.
We have started a study of an eddy-resolving high
resolution model with /x/ degrees on the Earth
Simulator, to understand effects of meso-scale eddies
on the CFCs distribution. As a preliminary study using
eddy-permitting high resolution model with /x/
degrees, its analysis shows that uptakes in the coastal
ocean and marginal seas are important globally for
both CFC- and anthropogenic CO .
During the last few years, the Carbon Cycle
Research Group has participated in the OCMIP, and
has started an experiment for interannual variability
for the next phase, OCMIP.
c. Paleoclimate Research Group
In FY, the coupled atmosphere-ocean GCM
(CGCM), which is planned to be used for the new
global warming studies in the IPCC frame work, was
installed on the Earth Simulator. The project is performed
as one of the MEXT's sub-projects. The coupled
atmosphere-ocean model without the so-called
'flux adjustment' with an intermediate resolution
(about km for atmosphere and to km for
ocean) was developed, tuned and tested against observational
data. Several test runs of transient CO
increase with the latest model versions are in progress.
In order to include ice sheet changes in the model
in future, an ice sheet model has been developed with
the collaboration of Center for Climate System
Research of the University of Tokyo (CCSR). The
model is applied for Greenland ice sheet and
Antarctica ice sheet as well as Northern Hemisphere
ice sheet that existed during the ice age.
A climate model of intermediate complexity is useful
not only for performing long-term variability
experiments but also for interpreting CGCM results.
One such model has been developed and tuned in
FY for the purpose of studies such as millennium
oscillation during the ice age. The model succeeds in
producing a reasonable sea ice distribution and deep
water formation near Norway as observed. The
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