- Acronym for Florida Atlantic Coast Transport Study.
See Rinkel (1986).
- Falkland Current
- See Malvinas Current.
- falling tide
- That interval of the tidal cycle between a
high water and the
following low water.
This is also known as ebb tide.
- Acronym for French-American Mid-Ocean Undersea Study.
See Heirtzler and Van Andel (1977).
- far infragravity waves
- Waves in the nearshore zone at periods ranging from 100 to 1000 seconds.
These were first discovered in 1986 as substantial energy in the velocity
field in that period range, although no accompanying sea surface elevation
signal was found, and their celerities were about an order of magnitude
too slow to be consistent with a gravity wave explanation.
They were eventually identified as shear waves arising from an
instability of the strong mean
The dynamics are analogous to large scale flows, but with the role
of the Coriolis force played by the
shear of the longshore current.
See Bowen and Holman (1989) and
- Faroe Shetland Channel
- See Turrell et al. (1999).
- Acronym for Frontal Air-Sea INteraction EXperiment, conducted from
1984 to 1986 in the subtropical convergence zone southwest of
Bermuda. The overall objective was to study air-sea interaction
on 1- to 100-km horizontal scales in a region of the open
ocean characterized by strong horizontal gradients in upper ocean
and sea surface properties. Among the specific questions addressed
by this investigation were how lower atmospheric fluxes vary
horizontally on scales determined by scales of oceanic variability,
how strong horizontal sea surface temperature gradients associated
with fronts affect the structure of the marine atmospheric boundary
layer, what the magnitudes of changes in surface roughness, stress,
and drag coefficients associated with cross-frontal gradients
in SST are, and others.
See Weller (1991) and
- 1. Acronym for flow actuated sediment trap.
2. Acronym for fore-aft scanning technique.
- Acronym for Fronts and Atlantic Storm Experiment, an experiment
scheduled to take place from Feb.-Mar. 1997 whose aim is to
advance the understanding and prediction of wintertime, oceanic,
extra-tropical weather systems. It is designed to improve the
forecasting of North Atlantic storms. See the
FASTEX Web site.
- Most generally this is a phenomenon where the output of a system
is fed or cycled back into the input of the system, thus changing
the output, etc. This is equivalent to saying that a system
- feeder current
- See rip feeder current.
- Ferrel, William (1817-1891)
- See Peterson et al. (1996).
- Ferrel cell
- A mid-latitude mean atmospheric circulation cell for weather proposed
by Ferrel in the 19th century. In this cell the air flows poleward
and eastward near the surface and equatorward and westward at higher
levels. This is now known to disagree with reality, although it
is sometimes used to describe a mid-latitude circulation identifiable
in mean meridional wind patterns.
- In surface gravity wave generation theories,
the length of water over which a wind is blowing. The wave height is
completely determined in such theories by the fetch, the duration
over which the wind blows, and the velocity of the wind.
See Kinsman (1984).
- Acronym for Flux, Etat de la mer et Télédétection en condition
de fetCH variable experiment in the Mediterranean Sea, which took place
in March and April 1998. The objective was to measure and parameterize
the turbulent fluxes at the ocean/atmosphere interface.
See Hauser et al. (2000).
- Acronym for First Global GARP Experiment, which took
place in 1970 and whose research objectives were to obtain a better
understanding of atmospheric motion for the development of more
realistic models for weather prediction and to assess the ultimate
limit of predictability of weather systems.
See Peixoto and Oort (1992) and the
FGGE Web site.
- Acronym for First International BIOMASS
- Fick's law
- A law stating that the mass of a solute crossing a unit area
per unit time in a given direction is proportional to the
gradient of solute concentration in that direction. For a
1-D process it can be stated as
where is the solute mass flux, the coefficient of
proportionality, the mass concentration of diffusing
solute, and the direction coordinate. The negative
sign indicates that transport is from high to low
concentrations. is called the diffusion coefficient or
the molecular diffusivity.
This was named for Adolf Fick, a German physiologist who
published a paper in 1855 entitled ``Uber Diffusion'' in
which he described the molecular diffusion process and
derived his law.
See Fischer et al. (1979).
- Acronym for Fluxes in the Deep Ocean instrument.
- In data or signal analysis, a function that selectively
discriminates against some of the information passing
through it. The discrimination is usually performed on
the basis of frequency.
- filtered equations
- Equations derived by modifying the equations of motion in various
ways. They are called filtered because the modifications filter
out or remove certain dynamical processes or solutions that are
deemed irrelevant to the phenomena being studied. Some oceanic
examples are the
beta plane and the
f plane approximations.
- filtering approximation
- See filtered equations.
- Findlater jet
- The atmospheric equivalent of an oceanic
western boundary current.
An example originates with the southwest monsoon that, fed partly
from a northward extension of the easterly trade winds over the
southern Indian ocean, develops in May. It turns northward and
crosses the Equator in the vicinity of the African coast, confined
by the highlands of Kenya and Ethiopia. This causes the winds
to assume the familiar jet-like structure seen in western boundary
currents in the oceans.
See Findlater (1974) and
Kraus and Businger (1994).
- Findlay, Alexander George (1812-1875)
- See Peterson et al. (1996).
- Fine Resolution Antarctic Model
- FRAM is a primitive equation numerical of the Southern Ocean between
latitudes 24S and 79S based on the Cox/Bryan model. See Group (1991)
and the FRAM Web site.
- fingerprint method
- A statistical technique developed to permit early detection of
possible greenhouse warming. This method
requires finding a
multivariate signal (i.e. changes in a number of different climate parameters
or changes in the same parameter at a number of different locations)
unique to enhanced greenhouse effect model simulations and
its accompanying identification in the observed climate record.
Thus the method simultaneously satisfies two essential requirements,
that the signal be both strong and unique. See
Wigley and Barnett (1990).
- finite element method
- A numerical approximation method in which data is represented
over some domain by a discrete series of functions. The domain
is divided into a finite number of subregions called elements,
whence the name. A series of functions is built up by defining
a simple function, e.g. a low-order polynomial, on each element
and requiring continuity between functions on adjacent subregions.
The points where values are used to define the functions are
conventionally called nodes and the defining parameters
Finite elements are distinguished from spectral methods in that
their approximations are local and not global, and they are
distinguished from finite differences because the function is
defined over a whole region rather than just a discrete points.
Their use is more prevalent in modeling solid structures such
as buildings or airplanes than it is for geophysical fluid flow,
although several authors have constructed circulation models
using finite elements. Perhaps their greatest advantage is the
relative ease with which highly irregular boundaries can be
handled as opposed to with the aforementioned spectral and
finite difference methods.
- fission-track dating
- A radioisotopic dating method
that depends on the tendency of uranium to undergo spontaneous
fission as well as the usual decay process.
The large amount of energy released in the fission process ejects
the two nuclear fragments into the surrounding material, causing
damage paths called fission tracks.
These number of these tracks, generally 10-20 in length, is a
function of the initial uranium content of the sample and of time.
The usefulness of this as a dating technique stems from the
tendency of some materials to lose their fission-track records
when heated, thus producing samples that contain fission-tracks produced
since they last cooled down. The useful age range of this technique
ranges from 100 to 100 million years BP, although error estimates are
difficult to assess and rarely given.
A problem with fission-track dating is that the rates of spontaneous
fission are very slow, requiring the presence of a significant amount
of uranium in a sample to produce useful numbers of tracks over time.
Additionally, variations in uranium content within a sample can lead to large
variations in fission track counts in different sample sections.
This method is used more often in archaeology than in paleoclimatology,
with other dating methods, e.g.
argon-argon dating, preferable
for the purposes of the latter field, although it can provide
useful results in the 30,000 to 100,000 years BP window that
strains the upper and lower limits of the other widely used
See Bradley (1985).
- More later.
- fjord entrainment estuary
- One of the four principal types of
estuaries as distinguished
by prevailing flow conditions.
This type features a relatively stagnant, deep
overlain by a thin river runoff flow, e.g. prevailing
summer conditions for the Norwegian fjords.
- Fjortoft's theorem
- A theorem that is a consequence of both
conserved in the two-dimensional flow an inviscid
homogeneous fluid. It states that the transfer of energy
from one scale to a smaller (larger) scale must be
accompanied by the simultaneous transfer to a larger (smaller)
scale. This result of 2-D turbulence contrast strongly
with those from 3-D turbulence where 3-D stretching and
twisting terms allow other avenues for energy transfer.
This is also known as the anti-cascade theorem.
See Hide (1978).
- Acronym for Family of Linked Atlantic Model Experiments, a framework
for several numerical ocean modeling projects that study the physics
and biogeochemistry of the Atlantic Ocean.
The goal of FLAME is to perform a series of sensitivity studies
with respect to key parameters of the ocean's dynamics.
- Acronym for Fladen Ground Experiment, a part of
- Acronym for Floating Instrument Platform.
FLIP Web site.
- Flores Sea
- See Gordon et al. (1994).
- Florida Bay
- See Wang (1998).
- Florida Current
- See Schmitz and Richardson (1991).
- The re-emission of light energy at a lower frequency by an
absorber illuminated with optical energy. The response is
usually immediate and on order 1 to 3% of the incident
- A device used to measure the concentration of
chlorophyll in sea water.
It does this by mimicking the sun and emitting a flash
of light at a specific wavelength and causing the
phytoplankton present to
fluoresce at another
wavelength. The light emitted by the plankton is
measured and converted to a chlorophyll measurement via
a calibration obtained from discrete measurements of known quantities
An a-c meter is also used to
- flux adjustment
- See flux correction.
- flux correction
- An ad hoc procedure by
which the values of dependent variables
at the air-sea interface in
coupled atmosphere-ocean model runs are adjusted to better conform to
observed values. For example, heat flux is corrected by first running
the ocean model and calculating the heat flux needed to correct the
differences between the observed and calculated surface temperatures.
Next the atmospheric model is run with observed values of SST and
the net heat flux from the atmosphere is calculated. The coupled
model is then run with the difference between these ocean and atmospheric
heat fluxes added to those calculated by the coupled model at each
time step. A similar procedure can be followed with other variables.
These methods are designed to remove most of the tendency of coupled models
to drift towards their own climate replete with
The most difficult area to apply this procedure is over ice.
It is expected that this will become much less of an issue as
the model components are improved.
See Sausen et al. (1988) and Meehl (1992).
- flux Richardson number
- A dimensionless number expressing the ratio of turbulent energy lost
to buoyant forces to the energy gained by eddy stress acting on the
mean shear. It is the crucial nondimensional number for turbulence
in stratified, shearing flow and can be expressed
in a couple of different ways by
where and are
or vertical transport coefficients
for heat and momentum, respectively, the
gradient Richardson number,
the friction velocity,
is von Karman's constant, and a length scale.
The definition of this is different than that for
the overall and
gradient Richardson numbers.
See Turner (1973) and Dutton (1986).