Ln-Lz

 

LOC

Abbreviation for limit of convection.

 

local elevation angle

The angle of the sun above the local horizon. This depends on the latitude and longitude of the location as

where is the time of day in Coordinate Universal Time, the local elevation angle, the latitude, the longitude, the solar declination angle, C the circle circumference, and the length of the day.

 

local range biozone

In biostratigraphy, a type of biozone in which the total known range of the zone fossil defines the limit of the unit. See Briggs and Crowther (1990), pp. 466-467.

 

LODYC

Abbreviation for Laboratoire de Physique de Océans.

 

loess

An unconsolidated sediment composed chiefly of silt-sized particles laid down by the wind.

 

LOICZ

Abbreviation for Land Ocean Interactions in the Coastal Zone, an IGBP project directed at an assessment of fluxes of matter between land, sea and atmosphere through the coastal zone; the responses of the land-sea interface to global change, particularl sea level rise; the biogeochemical responses of coastal systems to global change, with emphasis on the carbon cycle and exchanges of certain atmospheric trace gases; and the socio-economic implications of the degradation of the coastal zone and the need for development of new policies for the integrated management of coastal environments. See the LOICZ Web site.

 

LOIS

Acronym for Land-Ocean Interaction Study, the U.K. contribution to LOICZ. The project aims to quantify and simulate the fluxes and transformations of materials, e.g. sediments, nutrients, contaminants, into and out of the coastal zone, extending from the catchment to the edge of the continental shelf. The main study area is the U.K. East Coast from Berwick upon Tweed to Great Yarmouth, concentrating on the Humber River and its catchment. See the LOIS Web site.

 

Lombok Strait

A strait located between the islands of Lombok and Sumbawa in the Australasian Mediterranean Sea. This is one of many possible passages for the throughflow from the Pacific to the Indian Ocean. It is also one of the few passages where measurements have been made and shows an annual mean transport of around 1.7 Sv (of a total estimated at 20-30 Sv through the entire archipelago).

 

longshore bar

A ridge of sand running roughly parallel to the shoreline which may become exposed at low tide. There can be a series of these running parallel to one another at different water depths. See Komar (1976).

 

longshore current

See Komar (1976).

 

longshore trough

An elongated depression extending parallel to the shoreline and any longshore bars that are present and, like the longshore bars, there may be more than one present. See Komar (1976).

 

Loop Current

The continuation of the Mediterranean Current through the Yucatan Strait and on into the Gulf of Mexico. It is dynamically a western boundary current that separates from the shelf north of the Yucatan Strait, becomes unstable, and intermittently sheds anticyclonic eddies or rings into the Gulf of Mexico. The speed of the current has been estimated to be 1.0 m/s in Yucatan Strait, falling off to 0.4 m/s at 1000 m depth. A highly irregular southward flowing undercurrent has also been found in the 200 m above the sill depth.

 

LOPACC

Acronym for Late Quaternary Ocean Paleocirculation and Climate Change.

 

LORAN

Acronym for long-range navigation.

 

LOREX

Acronym for Lomonosov Ridge Experiment.

 

LOS

Abbreviation for Law of the Sea.

 

LOSS

Acronym for LAPS Observing System Simulation.

 

Lost Instrument Network

A clearinghouse created at WHOI to collect and broadcast information about lost and found oceanographic research equipment. It is implemented as a moderated mailing list to which interested parties can subscribe. See the Lost Instrument Network Web site.

 

LOTREX

Acronym for Land-Surface Traverse Experiment.

 

LOTUS

Acronym for Long Term Upper Ocean Study, Woods Hole, 1983., Woods Hole, 1983.

 

low

Abbreviated form of low pressure center.

 

Low Density XBT Network

A GOOS project to determine the monthly to interannual variability in the large-scale upper ocean heat constant via the operational deployment of XBT instruments from volunteer merchant ships. See the Low Density XBT Network Web site.

 

low pass filter

In data or signal analysis, a filter that passes frequencies below some cutoff frequency while attenuating higher frequencies.

 

low pressure center

In meteorology, a region of relatively low barometric pressure. These are characterized by upward moving air at altitude and convergence near the ground. These predominate in midlatitudes, i.e. around 40-50 . These are also known as cyclones and as such rotate clockwise/counterclockwise in the southern/northern hemisphere. Low pressure systems are generally characterized by clouds, precipitation, and occasionally thunderstorms, all of which are facilitated by the upward movement of moist air from near the ground.

 

lower high water (LHW)

The higher of two high waters on a day when the tide is neither The lower of two low waters on a day when the tide is neither predominantly diurnal nor predominantly semidiurnal but rather intermediate to either (a situation sometimes called a mixed tide).

 

lower high water interval (LHWI)

The time interval between the transit of the moon over either the local or Greenwich meridian and the next lower high water (LHW). This is generally used when the diurnal inequality is large.

 

lower low water (LLW)

The lower of two low waters on a day when the tide is neither predominantly diurnal nor predominantly semidiurnal but rather intermediate to either (a situation sometimes called a mixed tide).

 

lower low water interval (LLWI)

The time interval between the transit of the moon over either the local or Greenwich meridian and the next lower low water (LLW). This is generally used when the diurnal inequality is large.

 

LPO

Abbreviation for Laboratoire de Physique des Océans.

 

LROD

Abbreviation for Long-Range Overwater Diffusion, an experiment.

 

LSP

Abbreviation for Land Surface Parameterization scheme, and method for parameterizing plant growth, soil moisture, and other processes occurring at or near the land surface in terms of atmospheric GCM output variables (e.g. temperature, precipitation, etc.). Examples of LSPs are BATS, BEST, CLASS and SECHIBA.

 

LSW

Abbreviation for Labrador Sea Water.

 

LTE

See Laplace's tidal equations.

 

LTER

Abbreviation for the Long Term Ecological Research Program, established by the NSF to support research on long-term ecological phenomena in the U.S. See the LTER Web site.

 

LUCC

Acronym for Land Use/Cover Change, a core project of the IGBP designed to improve understanding and projections of the dynamics of land-use and land-cover change as inputs to and consequences of global environmental change and as elements of sustainable development. The research agenda consists of five themes: integrated global and regional models, land-cover patterns, land-use processes, database and classification development, and cross-scale or scalar dynamics. See the LUCC Web site.

 

lunear month

See synodic month.

 

lunation

See synodic month.

 

Luterbacher Predictive Model

A model, supported by CIESIN, foretelling impacts of global change on socioeconomic behavior.

 

Lutetian

The second of four ages in the Eocene epoch (the first of two ages in the Middle Eocene), lasting from 52.0 to 43.6 Ma. It is preceded by the Ypresian age and followed by the Bartonian age.

 

LWC

Abbreviation for liquid water content, a component of CWC.

 

lysimeter

An instrument for measuring the amount of water lost by evapotranspiration. It is a container of soil set on a balance or provided with some other means of measuring water content.

 

lysocline

The upper portion of the transition zone in sediments between supersaturated (shallow) and undersaturated (deep) sediments in the ocean. The transition is between the burial and dissolution of CaCO3 sediments. See Najjar (1991).