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- Ocean
Turbulence.
Part I:
One-Point
Closure
Model-Momentum
and Heat
Vertical
Diffusivities: Journal of
Physical
Oceanography,
Vol. 31, No.
6. (1 June
2001), pp.
1413-1426.Ocea
n mixing
processes have
traditionally
been
formulated
using
one-point
turbulence
closure
models,
specifically
the Mellor and
Yamada (MY)
models, which
were pioneered
in geophysics
using 1980
state-of-the-a
rt turbulence
modeling.
These models
have been
widely applied
over the
years, but the
underlying
core physical
assumptions
have hardly
improved since
the 1980s;
yet, in the
meantime,
turbulence
modeling has
made
sufficient
progress to
allow four
improvements
to be made.
1)<img
border="0&
#34;
src="/char
ent/iso_charac
ters_mixed/low
ercase/ensp.gi
f"/>Th
e value of
Ricr. MY-type
models yield a
low value for
the critical
Richardson
number, Ricr =
0.2 (the
result of
linear
stability is
Ricr = 1/4).
On the other
hand,
nonlinear
stability
analysis,
laboratory
measurements,
direct
numerical
simulation,
large eddy
simulation,
and mixed
layer studies
indicate that
Ricr ? 1. The
authors show
that by
improving the
closure for
the pressure
correlations,
the result
Ricr ? 1
naturally
follows.
2)<img
border="0&
#34;
src="/char
ent/iso_charac
ters_mixed/low
ercase/ensp.gi
f"/>No
nlocal,
third-order
moments
(TOMs). The
downgradient
approximation
used in all
models thus
far seriously
underestimates
the TOMs. A
new expression
that includes
both
stratification
and shear is
presented here
for the first
time. It is
obtained by
solving the
dynamic
equations for
the
third-order
moments.
3)<img
border="0&
#34;
src="/char
ent/iso_charac
ters_mixed/low
ercase/ensp.gi
f"/>Ro
tation. The
MY-type models
with rotation
assume that
the latter
does not
affect
turbulence,
specifically,
neither the
pressure
correlations
nor the rate
of dissipation
of turbulent
kinetic
energy. Recent
studies show
that both
quantities are
affected.
4)<img
border="0&
#34;
src="/char
ent/iso_charac
ters_mixed/low
ercase/ensp.gi
f"/>Mi
xing below the
mixed layer.
Thus far, the
momentum and
heat
diffusivities
below the
mixed layer
have been
treated as
adjustable
parameters. A
new model that
allows use of
the same
turbulence
model
throughout the
ocean depth is
proposed. A
new model is
presented that
includes 1),
2), and 4).
Rotation will
be dealt with
in a
subsequent
paper. The new
model is fully
algebraic and
easy to use in
an ocean code.
The new model
is used in an
OGCM, and the
predicted
global
temperature
and salinity
profiles are
compared with
those of the
KPP model and
Levitus
data.VM
Canuto, A
Howard, Y
Cheng, MS
Dubovikov
Source: Journal of Physical Oceanography, Vol. 31, No. 6. (1 June 2001), pp. 1413-1426. - Reconstruction
of the history
of
anthropogenic
CO2
concentrations
in the ocean: Nature In
Nature, Vol.
462, No. 7271.
(19 November
2009), pp.
346-349.The
release of
fossil fuel
CO2 to the
atmosphere by
human activity
has been
implicated as
the
predominant
cause of
recent global
climate
change1. The
ocean plays a
crucial role
in mitigating
the effects of
this
perturbation
to the climate
system,
sequestering
20 to 35 per
cent of
anthropogenic
CO2
emissions2, 3,
4. Although
much progress
has been made
in recent
years in
understanding
and
quantifying
this sink,
considerable
uncertainties
remain as to
the
distribution
of
anthropogenic
CO2 in the
ocean, its
rate of uptake
over the
industrial
era, and the
relative roles
of the ocean
and
terrestrial
biosphere in
anthropogenic
CO2
sequestration.
Here we
address these
questions by
presenting an
observationall
y based
reconstruction
of the
spatially
resolved,
time-dependent
history of
anthropogenic
carbon in the
ocean over the
industrial
era. Our
approach is
based on the
recognition
that the
transport of
tracers in the
ocean can be
described by a
Green's
function,
which we
estimate from
tracer data
using a
maximum
entropy
deconvolution
technique. Our
results
indicate that
ocean uptake
of
anthropogenic
CO2 has
increased
sharply since
the 1950s,
with a small
decline in the
rate of
increase in
the last few
decades. We
estimate the
inventory and
uptake rate of
anthropogenic
CO2 in 2008 at
140 25 Pg C
and
2.3 0.6 Pg C
yr-1,
respectively.
We find that
the Southern
Ocean is the
primary
conduit by
which this CO2
enters the
ocean
(contributing
over 40 per
cent of the
anthropogenic
CO2 inventory
in the ocean
in 2008). Our
results also
suggest that
the
terrestrial
biosphere was
a source of
CO2 until the
1940s,
subsequently
turning into a
sink. Taken
over the
entire
industrial
period, and
accounting for
uncertainties,
we estimate
that the
terrestrial
biosphere has
been anywhere
from neutral
to a net
source of CO2,
contributing
up to half as
much CO2 as
has been taken
up by the
ocean over the
same period.S
Khatiwala, F
Primeau, T
Hall
Source: Nature In Nature, Vol. 462, No. 7271. (19 November 2009), pp. 346-349. - Genomic
perspectives
in microbial
oceanography: Nature, Vol.
437, No. 7057.
(14 September
2005), pp.
336-342.Edward
Delong, David
Karl
Source: Nature, Vol. 437, No. 7057. (14 September 2005), pp. 336-342. - Phytoplankton
in a changing
world: cell
size and
elemental
stoichiometry: J. Plankton
Res., Vol. 32,
No. 1. (1
January 2010),
pp.
119-137.Global
increases in
atmospheric
CO2 and
temperature
are associated
with changes
in ocean
chemistry and
circulation,
altering light
and nutrient
regimes.
Resulting
changes in
phytoplankton
community
structure are
expected to
have a
cascading
effect on
primary and
export
production,
food web
dynamics and
the structure
of the marine
food web as
well the
biogeochemical
cycling of
carbon and
bio-limiting
elements in
the sea. A
review of
current
literature
indicates cell
size and
elemental
stoichiometry
often respond
predictably to
abiotic
conditions and
follow
biophysical
rules that
link
environmental
conditions to
growth rates,
and growth
rates to food
web
interactions,
and
consequently
to the
biogeochemical
cycling of
elements. This
suggests that
cell size and
elemental
stoichiometry
are promising
ecophysiologic
al traits for
modelling and
tracking
changes in
phytoplankton
community
structure in
response to
climate
change. In
turn, these
changes are
expected to
have further
impacts on
phytoplankton
community
structure
through as yet
poorly
understood
secondary
processes
associated
with trophic
dynamics.
10.1093/plankt
/fbp098Zoe
Finkel, John
Beardall,
Kevin Flynn,
Antonietta
Quigg, Rees,
John Raven
Source: J. Plankton Res., Vol. 32, No. 1. (1 January 2010), pp. 119-137. - A remote
monitoring
system for
Open Ocean
Aquaculture: Oceans '02
MTS/IEEE, Vol.
4 (2002), pp.
2488-2496
vol.4.The
purpose of
this project
was to
determine the
practicality
and
characteristic
s of a remote
monitoring
system for an
open ocean
aquaculture
fish cage. The
Open Ocean
Aquaculture
program at the
University of
New Hampshire
currently uses
two fish cages
to develop the
technology and
methodology to
raise finned
fish in the
open ocean.
The cages are
located about
six miles
offshore in
the Gulf of
Maine, making
daily
monitoring
both expensive
and time
consuming.
Scientists and
aquaculture
farmers,
therefore,
need a way to
remotely
observe fish
feeding habits
and growth on
a regular
basis without
having to
visit the
cages
themselves and
eventually
control the
feeding and
offshore
operations
monitoring
remotely. This
project was a
first-order
feasibility
study on the
utility of
using optical
and acoustic
sensors to
monitor the
submerged
North Atlantic
Halibut
(Hippoglossus/
hippoglossus)
fish cage, and
remotely
telemeter data
back to shore.
There,
scientists
will be able
to monitor the
status of the
fish and
feeding
operation.
Video and
sonar systems
were selected
to image fish
in the cage,
and a radio
telemetry
system was
tested on the
cage's feed
buoy. Imaging
capabilities
of the optical
and acoustic
systems, and
the data
transfer
capabilities
of the
telemetry
system were
tested.
Preliminary
results for
this
feasibility
test are
encouraging.
Adequate
imaging cannot
be
accomplished
by camera or
sonar alone.
Further
testing and
development is
required, but
after a
first-order
analysis of
results, a
dual system is
recommended
for fish cage
monitoring. In
addition, the
telemetry
system seems
feasible.APM
Michel, KL
Croff, KW
Mcletchie, JD
Irish
Source: Oceans '02 MTS/IEEE, Vol. 4 (2002), pp. 2488-2496 vol.4.
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