Outdoor Glossary: N

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Rate of change (as of January 1, 1900) in mean longitude of the Moon's node. N = 0.002,206,41 per solar hour.

Larger lunar elliptic semi diurnal constituent. See L2 Speed = 2T - 3s + 2h + p = 28.439,729,5 per solar hour.

Back of the neck. Synonym(s): hindneck, collar. In picture it is referred to as hindneck.

nasal canthus
Anterior corner of eye. No picture yet.

nasal fossa
Depression in which nostril is located.

refers to number of young individuals born or hatched per unit of time.

National Geodetic Vertical Datum of 1929 [NGVD (1929)]
A fixed reference adopted as a standard geodetic datum for elevations determined by leveling. The datum was derived for surveys from a general adjustment of the first-order leveling nets of both the United States and Canada. In the adjustment, mean sea level was held fixed as observed at 21 tide stations in the United States and 5 in Canada. The geodetic datum now in use in the United States is the National Geodetic Vertical Datum. The year indicates the time of the general adjustment. A synonym for Sea-level Datum of 1929. The geodetic datum is fixed and does not take into account the changing stands of sea level. Because there are many variables affecting sea level, and because the geodetic datum represents a best fit over a broad area, the relationship between the geodetic datum and local mean sea level is not consistent from one location to another in either time or space. For this reason, the National Geodetic Vertical Datum should not be confused with mean sea level.

National Park Service
The agency of the US Department of the Interior responsible for the administration of National Parks, Monuments, and Historic Sites. It is distinct from the USDA Forest Service both administratively and by mission.

National Tidal Datum Convention of 1980
Effective November 28, 1980, the Convention (1) establishes one uniform, continuous tidal datum system for all marine waters of the United States, its territories, Commonwealth of Puerto Rico, and Trust Territory of the Pacific Islands, for the first time in its history; (2) provides a tidal datum system independent of computations based on type of tide; (3) lowers chart datum from mean low water to mean lower low water along the Atlantic coast of the United States; (4) updates the National Tidal Datum Epoch from 1941 through 1959, to 1960 through 1978; (5) changes the name Gulf Coast Low Water Datum to mean lower low water; (6) introduces the tidal datum of mean higher high water in areas of predominantly diurnal tides; and (7) lowers mean high water in areas of predominantly diurnal tides. See chart datum.

National Tidal Datum Epoch
The specific l9-year period adopted by the National Ocean Service as the official time segment over which tide observations are taken and reduced to obtain mean values (e.g., mean lower low water, etc.) for tidal datums. It is necessary for standardization because of periodic and apparent secular trends in sea level. The present National Tidal Datum Epoch is 1960 through 1978. It is reviewed annually for possible revision and must be actively considered for revision every 25 years.

National Water Level Observation Network (NWLON)
The network of tide and water level stations operated by the National Ocean Service along the marine and Great Lakes coasts and islands of the United States. The NWLON is composed of the primary and secondary control tide stations of the National Ocean Service. Distributed along the coasts of the United States, this Network provides the basic tidal datums for coastal and marine boundaries and for chart datum of the United States. Tide observations at a secondary control tide station or tertiary tide station are reduced to equivalent l9-year tidal datums through the comparison of simultaneous observations with a primary control tide station. In addition to hydrography and nautical charting, and to coastal and marine boundaries, the Network is used for coastal processes and tectonic studies, tsunami and storm surge warnings, and climate monitoring. The National Water Level Observation Network also includes stations operated throughout the Great Lakes Basin. The primary network is composed of 54 sites with 139 seasonal gauge sites selectively operated 4 months annually for the maintenance of IGLD. The network supports regulation, navigation and charting, river and harbor improvement, power generation, various scientific activities, and the adjustment for vertical movement of the Earth's crust in the Great Lakes Basin.

natural barrier
A natural feature, such as a dense stand of trees or downfall, that will restrict animal travel.

natural disturbance
See disturbance.

natural range of variability
See range of variability

natural resource
A feature of the natural environment that is of value in serving human needs.

nautical mile
Also known as GEOGRAPHICAL MILE, its length is 1852 meters (6076.115 feet), approximately 1.15 times as long as the statute mile of 5280 feet.

The interface between atmosphere and ocean; air-sea interface; sea surface. Adjective, navifacial.

neap high water

neap low water

neap range
See neap tides.

neap tide
Tide of decreased range occurring semimonthly as the result of the moon being in quadrature. The NEAP RANGE of the tide is the average semidiurnal range occurring at the time of neap tides and is most conveniently computed from the harmonic constants. The NEAP RANGE is typically 10 to 30 percent smaller than the mean range where the type of tide is either semidiurnal or mixed and is of no practical significance where the type of tide is DIURNAL. The average height of the high waters of the neap tide is called NEAP HIGH WATER or HIGH WATER NEAPS (MHWN), and the average height of the corresponding LOW WATER is called NEAP LOW WATER or LOW WATER NEAPS (MLWN).

(1) In beach terminology an indefinite zone extending seaward from the SHORELINE well beyond the BREAKER ZONE. (2) The zone which extends from the swash zone to the position marking the start of the offshore zone, typically at water DEPTHS of the order of 20 m.

nearshore circulation
The ocean circulation pattern composed of the NEARSHORE CURRENTS and the COASTAL CURRENTS.

nearshore current
The current system caused by wave action in and near the BREAKER ZONE, and which consists of four parts the shoreward mass transport of water; longshore currents; rip currents; and the LONGSHORE movement of the expanding heads of rip currents.

Part connecting the head to the main part of the body.

(1) The narrow strip of land which connects a peninsula with the mainland, or connects two ridges. (2) The narrow band (rip) of water flowing seaward through the surf. See also RIP CURRENT.

neck patch
Inflatable sac on neck used by males in courtship display.

NEPA (National Environmental Policy Act)
Congress passed NEPA in 1969 to encourage productive and enjoyable harmony between people and their environment. One of the major tenets of NEPA is its emphasis on public disclosure of possible environmental effects of any major action on public lands. Section 102 of NEPA requires a statement of possible environmental effects to be released to the public and other agencies for review and comment.

Roughly triangular promontory of land jutting into the sea, often consisting of mobile material, i.e. a beach form.

nest cycle
the time required for a species to build a nest, lay and hatch eggs or give birth, and fledge or wean young. Most songbirds and small mammals will attempt to breed repeatedly during the breeding season.

nest survey
A way to estimate the size of a bird population by counting the number of nests in a given area.

A set consisting of; (a) stations for which geometric relationships have been determined and which are so related that removal of one station from the set will affect the relationships (distances, directions, coordinates, etc.) between the other stations; and (b) lines connecting the stations to show this interdependence.

Next Generation Water Level Measurement System (NGWLMS)
A fully integrated system encompassing new technology sensors and recording equipment, multiple data transmission options, and an integrated data processing, analysis, and dissemination subsystem.

NFLRMP (National Forest Land and Resource Management Plan)
Also called the Forest Plan or just the Plan, this document guides the management of a particular National Forest and establishes management standards and guidelines for all lands of that National Forest.

NFMA (National Forest Management Act)
This law was passed in 1976 and requires the preparation of Regional Guides and Forest Plans.

National Forest recreation sites that have been inventoried.

nictitating membrane
Translucent, vertical fold under the eye lid.

The cut made by waves in a shoreline of emergence.

A small tool used for clipping the tag ends of line after knots are tied

no action alternative
The most likely condition expected to exist in the future if management practices continue unchanged.

pertaining to animals that are active at night. Skunks are nocturnal; they move about most at night.

nodal line
A line in an oscillating body of water along which there is a minimum or no rise and fall of the tide.

nodal point
The no-tide point in an amphidromic region.

nodal zone
An area in which the predominant direction of the LONGSHORE TRANSPORT changes.

See lunar nodes.

node cycle
Period of approximately 18.61 Julian years required for the regression of the Moon's nodes to complete a circuit of 360 of longitude. It is accompanied by a corresponding cycle of changing inclination of the Moon's orbit relative to the plane of the Earth's Equator, with resulting inequalities in the rise and fall of the tide and speed of the tidal current.

node factor (f)
A factor depending upon the longitude of the Moon's node which, when applied to the mean coefficient of a tidal constituent, will adapt the same to a particular year for which predictions are to be made.

nodical month
Average period of the revolution of the Moon around the Earth with respect to the Moon's ascending node. It is approximately 27.212,220 days in length.

renewable resource- A resource whose total quantity does not increase measurably over time, so that each use of the resource diminishes the supply.

non tidal current
See current.

noncommercial vegetative treatment
The removal of trees for reasons other than timber production.

nonconsumptive use
The use of a resource that does not reduce the supply. For instance, bird watching is a non-consumptive use of wildlife. Boating and fishing are non-consumptive uses of water.

Wildlife species that are not hunted for sport.

nongame animals
any wild animal that cannot be legally hunted or trapped.

nonharmonic constants
Tidal constants such as lunitidal intervals, ranges, and inequalities which may be derived directly from high and low water observations without regard to the harmonic constituents of the tide. Also applicable to tidal currents.

nonpoint source pollution
Pollution whose source is not specific in location. The sources of the discharge are dispersed, not well defined, or constant. Rain storms and snowmelt often make this type of pollution worse. Examples include sediments from logging activities and runoff from agricultural chemicals.

Nontarget wildlife
are species that are impacted by a management practice (e.g., pesticide) that is directed towards another species. For example, an insecticide applied to control weevils (target species) in some crop may kill some bird species (nontarget species).

normal tide
A nontechnical term synonymous with tide; i.e., the rise and fall of the ocean due to the gravitational interactions of the Sun, Moon, and Earth alone. Use of this term is discouraged.

North American Vertical Datum of 1988 (NAVD 88)
A fixed reference for elevations determined by goedetic leveling. The datum was derived from a general adjustment of the first-order terrestrial leveling nets of the United States, Canada, and Mexico. In the adjustment, only the height of the primary tidal bench mark, referenced to the International Great Lakes Datum of 1985 (IGLD 85) Local mean sea level height value, at Father Point, Rimouski, Quebec, Canada was held fixed, thus providing minimum constraint. NAVD 88 and IGLD 85 are identical. However, NAVD 88 bench mark values are given in Helmert orthometric height units while IGLD 85 values are in dynamic heights. See International Great Lakes Datum of 1985, National Geodetic Vertical Datum of 1929, and geopotential difference.

North Atlantic Current
A North Atlantic Ocean current setting northeastward from southeast of the Grand Banks at about latitude 40 north, longitude 50 west, to the British Isles. A segment of the Gulf Stream System, the A North Atlantic Current continues the flow of the Gulf Stream to the Norwegian and Canary Currents.

North Cape Current
An Arctic Ocean current setting eastward off the north coast of Scandinavia in the Barrents Sea.

North Equatorial Current
A current setting westward in the North Atlantic and North Pacific Oceans and in the Indian Ocean from about October to July. It occurs immediately north of the Equatorial Counter Current.

North Pacific Current
A North Pacific Ocean current setting eastward from about 160 east to somewhat beyond about 150 west. It continues the flow of the Kuroshio Extension, sending branches to the south.

Norwegian Current
A North Atlantic Ocean current setting northeastward off the coast of Norway.

External naris.

notice of intent
A notice in the federal register of intent to prepare an environmental impact statement on a proposed action.

The process of replenishing a BEACH. It may be brought about naturally, by LONGSHORE TRANSPORT, or artificially by the deposition of dredged materials.

nu (v2)
Larger lunar evectional constituent. See lambda. Speed = 2T - 3s + 4h - p = 28.512,583,1 per solar hour.

nutrient cycle
The ciculation of chemical elements and compounds, such as carbon and nitrogen, in specific pathways from the non-living parts of ecosystems into the organic substances of the living parts of ecosystems, and then back again to the non-living parts of the ecosystem. For instance, nitrogen in wood is returned to the soil as the dead tree decays; the nitrogen again becomes available to living organisms in the soil, and upon their death, the nitrogen is available to plants growing in that soil.

A strong synthetic fiber that maintains elasticity while retaining its shape

An artificial fly tied to imitate an immature, underwater insect; also the stage between egg and adult in the lifecycle of insects that undergo incomplete metamorphoses, such as mayflies and stoneflies


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