Fn-Fz

 

FNMOC

Abbreviation for the Fleet Numerical Meteorology and Oceanography Center, a center that specializes in meteorology, oceanography, and satellite and satellite-derived imagery on a global scale. FNMOC products are made available via a distribution system called NODDS. See the FNMOC Web site.

 

FNOC

Abbreviation for Fleet Numerical Ocean Center. See Clancy (1992).

 

FOCAL

Acronym for Programme Francais Ocean et Climat dans l'Atlantique Equtorial. See Katz (1987) and Richardson and Reverdin (1987).

 

fohn wind

A warm, dry wind which blows to the lee of a mountain range, prevalent on the northern slopes of the Alps.

 

folkloric winds

This refers to the colorful names that have been given to winds that appear in specific geographic locations and/or at certain times of the year. Examples are abroholos, baguio, barat, bise, bora, buran, chinook, etesian, gregale, haboob, harmattan, khamsin, kosava, leste, levanter, leveche, libeccio, maestro, mistral, pampero, reshabar, rrashaba, scirocco, seistan wind, shamal, simoom,solano, sumatra, tramontona, vardarac, vendavales, and zephyr.

 

Foraminifera

An order of Sarcodina, the members of which have numerous fine anastomosing pseudopodia and a shell which is calcareous; the shells of these organisms, when deposited in ocean sediments, are the source of climatic information about ancient temperatures.

 

forest succession model

A type of vegetation dynamics model that represents regeneration, growth and mortality of statistical populations of individual plants on a plot whose size reflects the scale of competition. Such models simulation the natural cyclical behavior of ecosystems if no environmental change is specified. See Shugart (1984).

 

formation

In lithostratigraphy, the fundamental and mappable unit based upon the lithology of the rocks included within it. See Briggs and Crowther (1990), p. 462.

 

formation type

A group of convergent plant formations occurring on different continents.

 

fossil fuel

Coal, petroleum, or natural gas or any fuel derived from these sources. The burning of these is a significant anthropogenic source of the greenhouse gas carbon dioxide.

 

fossilized mixing region

In physical oceanography, this refers to the water trapped between the depths of the summer and winter mixed layers. This is a key feature in the formation of Central Water via the process of subduction. See Tomczak and Godfrey (1994).

 

fossil turbulence

In the ocean, temperature microstructure that remains after the turbulence that presumably created it decays, i.e. there is no velocity microstructure. See Turner (1973).

 

Fourier analysis

The determination of the harmonic components of a complex waveform, i.e. the terms of a Fourier series that represents the waveform.

 

f plane approximation

In oceanography, a coordinate system approximation where the Coriolis parameter f is, in a simplified form of the equations of motion, assumed to be a constant. The dynamics as such take place in a plane tangent to the surface of the Earth where f everywhere takes its value at the point of tangency. This approximation holds reasonably well over latitudinal distances over which f doesn't vary much (i.e. a few degrees) or over a few tens of degrees near the poles where f varies slowly. See Gill (1982).

 

fps

Abbreviation for the foot-pound-second system of units.

 

fractal cloud models

A type of inhomogeneous cloud model used to parameterize cloud properties. The fractal models are used to study the dependence of effective cloud parameters of macrostructural parameters such as the variance and wavenumber spectra of cloud liquid water. See the fractal cloud Web site.

 

FRAM

Acronym for Fine Resolution Antarctic Model.

 

free atmosphere

In meteorology, the part of the troposphere above the planetary boundary layer. It is free of the influence of the earth's surface and, on the average, slightly stable.

 

free-living nitrogen fixation

The process where cyanobacteria and some heterotrophic bacteria can fix nitrogen without symbiotic assocations. The cyanobacteria are important in many aquatic ecosystems and in exposed soil crusts in a few terrestrial ecosystems, but light limits their importance in most soils. See Davidson (1995).

 

FRH

Abbreviation for Fixed Relative Humidity.

 

friction velocity

A velocity calculated via dimensional analysis that defines the velocity scale for the flow near a wall. This is also called the dynamic velocity. See Kagan (1995).

 

fringing reef

One of three main geomorphological types of coral reefs, the other two being barrier reefs and atolls. These are formed close to shore on rocky coastlines by the growth of corals and associated hydrozoans, alcyonarians and calcareous algae. Fragments of limestone derived from such bioherms are welded together by the encrusting calcareous algae as well as by the deposition of interstitial calcium carbonate cement, the latter brought about by geochemical reactions and possibly bacterial action. The zone of living corals is separated from the shore by a shallow reef flat where reduced circulation, periods of tidal emersion, and the accumulation of sediments inhibit coral growth. See Barnes and Hughes (1988).

 

Froude number

In fluid mechanics, a dimensionless parameter expressing the ratio of nonlinear advection to the pressure gradient acceleration associated with the variation of fluid depth, i.e. of the fluid speed to a measure of the internal wave speed. It is defined by

where u is the flow velocity, g the gravitational acceleration, and H the fluid depth, and the approximate phase speed of shallow water gravity waves. A Froude number greater than unity is indicative of what is called supercritical flow, and one less than unity of subcritical flow.

When dealing with internal waves, an internal or densimetric Froude number is defined which corresponds to the ordinary Froude number with with the reduced gravity g' replacing g in the above. See Turner (1973) and Houze (1993).

 

full moon

In tidal mechanics, the times when the Earth-centered longitudes of the Sun and Moon differ by 180 degrees, i.e. they are in opposition. At such times the Moon is completely opposite the Sun and fully illuminated. Spring tidesspringtide occur during full moons.

 

functional compensation hypothesis

The hypothesis that species overlap with one another in functional properties to a sufficient degree that the loss of any one species has negligible effects on an ecosystem. There is no countervailing hypothesis since there is little or no evidence that each species plays such a unique role that its absence would result in dramatic changes in an ecosystem. This is also known as the redundancy hypothesis. See Heywood (1995).

 

fusain

Fossilized charcoal. This is almost pure carbon and the product of ancient wildfires. The presence of this is a useful paleoclimate indicator in that the susceptibility of an environment to fire is influenced by the climate, with fire-prone environments predominantly being those experiencing a burst of seasonal growth (triggered by rains) followed by seasonal drought, with the droughts ending with thunderstorms that produce lightning but not always rain. See Sellwood and Price (1994).