Outdoor Glossary: O
O1 Lunar diurnal constituent. See K1. Speed = T - 2s + h =
13.943,035,6 per solar hour.
obliquity factor A factor in an expression for a constituent tide
(or tidal current) involving the angle of the inclination of the Moon's orbit to
the plane of the Earth's Equator.
obliquity of the ecliptic The angle which the ecliptic makes with
the plane of the Earth's Equator. Its value is approximately 23.45.
obliquity of the Moon's orbit The angle which the Moon's orbit
makes with the plane of the Earth's Equator. Its value varies from 18.3 to
28.6, depending upon the longitude of the Moon's ascending node; the smaller
value corresponding to a longitude of 180 and the larger one, to a longitude of
0.
occiput Rear portion of crown. Synonym(s): hindhead.
Ocean The great body of salt water which occupies two-thirds of the
surface of the Earth, or one of its major subdivisions.
ocean current A nontidal current constituting a part of the general
oceanic circulation.
oceanography The science of all aspects of the oceans, in spite of
its etymology. The term, oceanography, however, implies the interrelationships
of the various marine sciences of which it is composed. This connotation has
arisen through the historical development of marine research in which it has
been found that a true understanding of the oceans is best achieved through
investigations based on the realization that water, its organic and inorganic
contents, motions, and boundaries are mutally related and interdependent.
offshore (1) In beach terminology, the comparatively flat zone of
variable width, extending from the SHOREFACE to the edge of the CONTINENTAL
SHELF. It is continually submerged. (2) The direction seaward from the shore.
(3) The zone beyond the nearshore zone where sediment motion induced by waves
alone effectively ceases and where the influence of the sea bed on wave action
is small in comparison with the effect of wind. (4) The BREAKER ZONE directly
seaward of the LOW TIDE line.
offshore breakwater A BREAKWATER built towards the seaward limit of
the LITTORAL ZONE, parallel (or nearly parallel) to the shore.
offshore currents (1) Currents outside the surf zone. (2) Any
current flowing away from the shore.
offshore wind A wind blowing seaward from the land in the coastal
area.
old growth Old forests often containing several canopy layers,
variety in tree sizes and species, decadent old trees, and standing and dead
woody material.
onshore A direction landward from the sea.
onshore current Any current flowing towards the shore.
onshore wind A wind blowing landward from the sea.
OO1 Lunar diurnal, second-order, constituent. Speed = T + 2s + h =
16.139,101,7 per solar hour.
open sea Same as HIGH SEAS.
operculum Swollen structure in pigeons overarching the
nostril.
opposable describes the position of the thumb relative to the
fingers. An opposable thumb allows raccoons to grasp and manipulate small
objects.
opposing winds A wind blowing in the opposite direction to that in
which the waves are travelling.
ordinary With respect to tides, the use of this nontechnical word
has, for the most part, been determined to be synonymous with mean. Thus,
ordinary high (low) water is the equivalent of mean high (low) water. The use of
ordinary in tidal terms is discouraged.
ordinary high water mark (OHWM) (SMP) That mark that will be found
by examining the bed and banks and ascertaining where the presence and action of
waters are so common and usual, and so long continued in all ordinary years, as
to mark upon the soil a character distinct from that of the abutting upland, in
respect to vegitation as that condition exists on June 1, 1971, as it may
naturally change thereafter, or as it may change thereafter in accordance with
permits issued by a local government or the department
ordinary tide This expression is not used in a technical sense by
the U.S. Coast and Geodetic Survey, but the word "ordinary" when applied to
tides, may be taken as the equivalent of the word "mean". Thus "ordinary HIGH
WATER LINE" may be assumed to be the same as "mean high water line".
organic soil Soil at least partly derived from living matter, such
as decayed plant material.
orifice See stilling well and protective well.
orthophotograph A photograph prepared from a perspective photograph
by removing distortions and displacements of points caused by tilt, relief, and
perspective.
orthophotomap A map made by assembling a number of orthophotographs
into a single, composite picture.
ORV Off-road vehicles, such as motor cycles, 4-wheel drive
vehicles, and 4-wheelers.
oscillation A periodic motion backward and forward. To vibrate or
vary above and below a mean value.
outcrop A surface exposure of bare rock, not covered by soil or
vegetation.
outer primaries Group of primaries farthest from the body.
outer secondaries Group of secondaries farthest from the
body.
outer tail feathers Part of the tail farthest from the
center.
outer wing Alula and primaries.
outfall (1) The vent of a river, drain, etc. (2) A structure
extending into a body of water for the purpose of discharging sewage, storm
runoff or cooling water.
outflanking EROSION behind or around the inner end of a GROIN or
BULKHEAD, usually causing failure of the structure.
overfalls Breaking waves caused by a conflict of currents, or by
the wind moving against the current.
overfishing To fish to the detriment of (a fishing ground) or to
the depletion of (a kind of organism); to fish until all the fish are gone
overmature timber Trees that have attained full development,
particularly in height, and are declining in vigor, health, and soundness.
oversplash The water that splashes over the top of a BREAKWATER,
seawall, etc.
overstory The upper canopy layer; the plants below comprise the
understory.
overtide A harmonic tidal (or tidal current) constituent with a
speed that is an exact multiple of the speed of one of the fundamental
constituents derived from the development of the tide-producing force. The
presence of overtides is usually attributed to shallow water conditions. The
overtides usually considered in tidal work are the harmonics of the principal
lunar and solar semi diurnal constituents M2 and S2, and are designated by the
symbols M4, M6, M8, S4, S6, etc. The magnitudes of these harmonics relative to
those of the fundamental constituents are usually greater in the tidal current
than in the tide.
overtopping Water carried over the top of a COASTAL DEFENSE due to
wave run-up or surge action exceeding the crest height.
overwash (1) The part of the UPRUSH that runs over the crest of a
BERM or structure and does not flow directly back to the ocean or lake. (2) The
effect of waves overtopping a COASTAL DEFENSE, often carrying sediment landwards
which is then lost to the beach system.
oyashio A current setting southwestward along the Siberian,
Kamchatka, and Kuril Islands coasts in the Bering Sea and North Pacific Ocean.
|