Cn-Cz

cnoidal wave

A periodic wave that can have widely spaced sharp crests separated by wide troughs, not unlike the wave froms just outside the breaker zone near the shore. Limiting cases of cnoidal waves include solitary waves (when the wave period becomes infinite) and Airy waves, although the mathematical difficulties of the theory have kept it from such wide application. The cnoidal wave profile is given by

$$\eta\,=\,H\,{\text{cn}^2}\,\left[2K(\kappa )\left({x\over L}\,-\, {t\over T}\right),\,\kappa\right]$$

where $L$ is the wavelength, $T$ the period, $H$ the wave height, $K(\kappa )$ the complete elliptic integral of the first kind of modulus $\kappa$, $\eta$ the coordinate of the water surface above the trough level at the horizontal coordinate $x$, and cn$(r)$ the Jacobian elliptic function of $r$ (from whence comes ``cnoidal'' analogous to ``sinusoidal''). See Komar (1976) and LeMehaute (1976).

COADS

Acronym for Comprehensive Ocean Air Data Set, a CGCP program to update and enhance the most extensive and widely used set of surface marine data available for the global ocean over the past 150 years. See the COADS Web site.

COAMPS

Acronym for Coupled Ocean Atmosphere Mesoscale Prediction System, a numerical weather prediction model of the NRL.

COARE

Acronym for Coupled Ocean-Atmosphere Response Experiment, a TOGA experiment conducted in thr equatorial western Pacific from November 1992 through February 1993. The stated aims of COARE were to describe and understand:

• the principal processes responsible for the coupling of the ocean and atmosphere in the western Pacific warm pool system;
• the principal atmospheric processes that organize convection in the warm pool region;
• the oceanic response to combined buoyancy and wind stress forcing in the western Pacific warm pool region; and
• the multiple scale interactions that extend the oceanic and atmospheric influence of the western Pacific warm pool system to other regions and vice-versa.

Additional information can be found at the TOGA COARE Web site. See Webster and Lukas (1992) and ().

COAST

A 5-year interdisciplinary research project on cross-shelf transport processes in a wind-driven system. This is sponsored by the NSF and part of the CoOP program. The program consists of field experiments off the Oregon coast along with coordinated ocean circulation, ecosystem and atmospheric modeling. COAST started in early 2000, with major field work taking place in summer 2001 and winter 2003. The major participants are Oregon State University, the University of North Carolina and LDEO.

[http://damp.oce.orst.edu/coast/]

COAST

Acronym for Coastal Observation and Simulations with Topography, a PMEL program. COAST was conducted from Nov. 30 to Dec. 15, 1993 and the purpose was to collect the observations needed to document and ultimately anticipate the influence of orography on mesoscale weather phenomena in coastal environments. The objectives were:

• to identify conditions that contribute to the development of coastally trapped disturbances during periods of strong but relatively uniform onshore flow; and
• to observe the mesoscale structure of fronts and other features associated with baroclinic cyclones over the open sea, and describe their evolution as they come under the influence of orography.

[http://www.atmos.washington.edu/~gcg/MG/coastsum.html]

Coastal Mixing and Optics Project (CMO)

A project funded by ONR and performed by the Ocean Physics Laboratory at ICESS. The objective is to determine how particles and optical properties respond to physical forcing under various oceanic conditions on a broad continental shelf off the east coast of the U.S. This will be done by collecting time series of optical and physical data from several depths using a variety of newly developed optical and physical instruments placed on a mooring at a mid-shelf location. See the CMO Web site.

coastal trapped wave

To be completed.

COASTWATCH

See Espedal et al. (1998).

COBSEA

Acronym for Co-ordinating Body of the Seas of East Asia.

CODAR

Acronym for Coastal Ocean Dynamics Applications Radar.

CODE

Acronym for Coastal Ocean Dynamics Experiment, a program to study shelf processes that took place north of San Francisco during the summers of 1981-1982. The program employed drifters, hydrographic measurements, Doppler-acoustic surveys, wind measurements, and remote sensing to study a prominent, persistent filament near Point Arena. It was notable for the first integrated use of remote sensing for a study of this magnitude, the first coastal use of the ADCP, and the introduction of a new generation of high quality near-surface drifters. It led to a clear understanding of regional scale wind driving and provided a moored array data set still uses as the standard to test models. See Davis (1985), Winant et al. (1987) and Lentz and Beardsley (1991).

COHMAP

The Cooperative Holocene Mapping Project (COHMAP) was an initiative to assemble a global array of well-dated paleoclimate data and use a GCM to identify and evaluate causes and mechanisms of climate change over the last 18,000 years. See Project (1988).

COLD

Acronym for Coupled Ocean-Ice Linkages and Dynamics, a research program whose components include LTER, RACER and SANTA CLAuS. See the COLD Web site.

cold start problem

In climate modeling, this is a problem that results from beginning a model simulation at a point in time when the climate response to natural and anthropogenic forcing that happened before the start of the simulation is already in progress. An example would be specifying 1950 initial conditions for a simulation of the effects of anthropogenic CO2 increases when the CO2 increases although the CO2 increases started in the latter half of the 19th century. This results in a simulation that is missing at least 50 years of the time evolution of the modeled system's response to increasing atmospheric CO2, which can be vital to the prediction of future states of a system with components that change on time scales greater than 50 years, e.g. the ocean.

Columbia Current (CC)

According to Strub et al. (1998):

The Columbia Current flows to the north next to the coast off northern Ecuador and Columbia and is strongest in austral winter (August). It is confined to the top 100 m, reaches velocities of order 1.0 m s$^{-1}$ and stays within 100-200 km of the coast. During most periods, it forms the eastern limb of a cyclonic gyre that fills the Panama Bight.

See Wooster (1959) and Strub et al. (1998).

Columbia River Estuary

See Sherwood et al. (1990).

COMAR

Acronym for Coastal Marine Program, a UNESCO project.

Comprehensive Ocean Air Data Set

This is an extensive data set that was created by combining, editing and summarizing global in situ marine data from many sources. It covers the period 1854-1992. It is a cooperative project among ERL, NOAA, the NCDC, CIRES and NCAR. Extensive hypertext documentation is available. There is also a further processed version of this data set called UWM/COADS. See Woodruff et al. (1987).

computational grid

A mapping of discrete points onto a continuum (e.g. the ocean, the atmosphere, etc.) to comprise a grid-like structure. This is done to enable a numerical solution of the equations governing the specific continuum in cases where analytical solutions are impossible or infeasible due to irregular boundary conditions, nonlinearities in the governing equations, or some combination thereof. A discretized version of the equations is solved at each point in the grid, and the collection of these solutions is combined (usually graphically) to recover a continuum-like solution. It is hoped that this solution well approximates the hypothesized correct solution.

computational mode

An artifact of numerical solution procedures that use a centered scheme for temporal advancement, i.e. one that requires information at three time levels. Starting such a scheme requires two independent initial conditions, one specified and the other calculated from this using a temporal scheme requiring only two time levels. This results in a solution that is actually the sum of two solutions, one related to the actual physics of the problem and the other purely an artifact of the numerical procedure. The numerical solution usually alternates at each time step, resembling a sawtooth wave over time, and can be damped by averaging the solution over two consecutive time steps at suitably chosen intervals. See Kowalik and Murty (1993).

concentration basin

See mediterranean sea.

CONFLUENCE

A program to investigate the upwelling region and mixing of the Rio Plata into the southwest Atlantic Ocean.

conservation laws

More later.

consistency

In numerical modeling, a numerical computational scheme is said to be consistent if the discrete algebraic equations created by the process of discretization recover or reduce to the original continuum differential equations as the spacing in the computational grid is shrunk to zero. The scheme is said to be unconditionally consistent if the above is true no matter how (i.e. in what order, etc.) the grid is shrunk. Thus consistency deals with relations between equations in their continuum versus discrete forms, as opposed to convergence.

continental rise

More later.

continental shelf

Much more later.

continental slope

The relatively steep slope usually found between the continental shelf and the abyssal plain. Continental slopes range from 3 to 6$^\circ$ in slope (with 4$^\circ$ being about average), range in depth from 100-300 m to 1400-3200 m, range in width from 20-100 km, and occupy about 8.5% of the ocean floor if the 2000 m contour is taken as the deeper border. The continental shelf and slope are said to comprise the continental margin.

Continental Slope Current

A persistent poleward flow over the continental slope region off northwestern Europe. It is thought to originate as far south as the Armorican Slope region off the west coast of northern France, and flows north past the exit of the Faroe-Shetland Channel. This current supplies the saltiest and warmest water exchanged over the Greenland-Scotland Ridge, a water mass known as North Atlantic Water. See Hansen and Osterhus (2000) and the references therein.

continental shelf oceanography

See Allen et al. (1983), Brink (1987), Walsh (1988), Brink (1991) and Huyer (1990).

continental shelf wave

To be completed.

Continental Water Boundary (CWB)

In physical oceanography, a frontal region in the Southern Ocean located at around 61-62$^\circ$ S that separates the Continental Zone to the south and its separate water mass of uniform temperature and low salinity in the upper 500 m from the Antarctic Zone to the north. The term was introduced to demarcate the northern limit of a cold water mass (colder than about 0$^\circ$C) near the South Shetland Islands having a subsurface isothermal layer extending from about 150 m depth to more than 500 m. See Tomczak and Godfrey (1994), pp. 76. This is also known in the Weddell Sea region as the Weddell Gyre Boundary.

Continental Zone

In physical oceanography, a region in the Southern Ocean between the Southern ACC Front and the continent of Antarctica. It is characterized hydrographically by a water mass of uniform temperature and low salinity in the upper 500 m. The CZ is one of four distinct surface water mass regimes in the Southern Ocean, the others being (to the north) the Antarctic Zone (AZ), the Polar Front Zone (PFZ) and the Subantarctic Zone (SAZ). See Orsi et al. (1995).

continuity equation

See ().

continuous plankton meter

A device used by biological oceanographers to provide continuous qualitative and quantitative records of plankton distribution and patchiness when studying swarms over large areas. The meter is a square or round torpedo-shaped tube about 1 m long that is towed behind a ship underway at full speed. There is a small entrace hole in the front end which leads to a wider tunnel across which a band of silk gauze is stretched. This gauze is slowly wound from one spool to another via a propeller mechanism attached to the outside of the meter, thus being linked to the speed of the meter and therefore the distance it has traveled. Data gathered with the meter is considered supplementary to other types of net tow data gathered separately at individual stations. See Sverdrup et al. (1942).

contra solem

A term introduced by V. W. Ekman in 1923 to describe motion turning to the left (right) in the northern (southern) hemisphere, i.e. cyclonic motion. This is the reverse of cum sole.

contrail cirrus

A type of cloud hypothesized to form when water vapor within jet aircraft plumes undergoes homogeneous and/or heterogeneous nucleation processes upon which ice particles form and grow. They persist for only a short time if the ambient air is dry, but may last for minutes to hours and spread into linear formations a few kilometers in width and tens of kilometers in width if humid conditions prevail. They also tend to cluster in groups. Various investigations attempting to show a connection between them have at least showed a correlation between increased use of jet fuel in some regions and the average annual number of clear days. See Liou (1992).

convective adjustment

In the numerical modeling of ocean circulation, this is a process wherein, after each time step, the vertical potential density gradient is calculated and, if densier water anywhere overlies lighter water, the densities are mixed such that a state of either a neutral or slightly positive stability is created. This process numerically mimics the convective overturning processes observed and inferred in the real ocean at locations such as the Weddell Sea, although the real process takes place at spatial scales on the order of a kilometer or less while the model resolution is such that the spacing between grid points is usually much greater than this.

convergence

In numerical modeling, a numerical computational scheme is said to be convergent is the solutions to the discrete algebraic equations created by the process of discretization approach the solutions of the original continuum differential equations as the spacing in the computational grid is shrunk to zero. Thus convergence deals with relations between solutions of equations in their continuum versus discrete forms, as opposed to consistency.

CONVEX-91

Acronym for CONtrol Volume EXperiment, 1991, a survey designed to investigate the shape and strength of the Northeastern sector of the North Atlantic subpolar gyre, and to examine the exchanges between the upper and deep waters of the area. This was part of the Gyre Dynamics Experiment, itself part of WOCE core project 3. See Read (2001).

conveyor belt

A simple model of a closed global thermohaline interbasin exchange circulation scheme introduced by Broecker (1987), Broecker (1991), and Gordon (1986). Cold and salty deep water formed in the Norwegian/Greenland Sea (called NADW) flows southward as a deep current where around 30% is transported via the ACC to the Indian and Pacific Oceans. The flow travels northward along the western boundaries of these oceans and upwells in the northern portions. This drives a warm, shallow return flow that travels from the Northern Pacific through the Indonesian Archipelago and the Indian Ocean (gaining the water upwelled there) towards the South Atlantic via the southern tip of Africa. There it is joined by the remaining 70% that mixed with AAIW and returned to the South Atlantic via the Drake Passage. A general northward flow returns the water to the North Atlantic. The regions of deep water formation around Antarctica form AADW which flows under and mixes with the NADW, forming another component in the mixture. This is a simple (and to some an overly simplistic) view of the thermohaline circulation, but it is useful as a first order description. A more complete and accurate version of the interbasin exchange circulation pattern has been developed.

cooscillating tide

The tide created in an estuary caused by the ocean tide at the entrance to the estuary acting as a driving force. See Officer (1976).

COPE

Acronym for Coastal Ocean Probing Experiment, a NOAA ETL experiment which took place in 1995. The objectives were to determine how environmental conditions affect observations of internal waves with active and passive microwave sensors, to develop improved instrumentation and techniques for observation of the air-sea interface, and to evaluate new scattering theories. See Trokhimovski et al. (2000). See the COPE Web site.

COPS

Acronym for Coastal Ocean Prediction Systems Program.

coral bleaching

A phenomena wherein coral reefs bleach as a result of high temperatures or other environmental stresses, e.g. pollution episodes. Observations indicate that since 1979 bleaching episodes have coincided with El Nino war events and suggest that the scale of bleaching since 1979 is unprecedented since 1870. See Goreau and Hayes (1994) and Glynn (1993).

coral reef

A limestone structure found in relatively shallow water composed of corals, organisms that secrete limestone foundations to provide structural support and protection. There are three geomorphologically distinct types of coral reefs, fringing reefs, barrier reefs, and atolls, although there are gradations between these types. All these types have the same basic biological structure and result from the same processes of accretion. See Wells (1957) and Barnes and Hughes (1988).

Coral Sea

A marginal sea located in the southwest Pacific centered at about 155$^\circ$ E and 14$^\circ$ S off of the northeast coast of Australia. It is also bordered by the Solomon Islands and Papua New Guinea to the north and west, New Caledonia and the New Hebrides Islands to the east, and abuts the Tasman Sea to the south. The bathymetry is essentially composed of the Solomon Basin to the northwest, the Coral Sea Basin in the center, and the New Hebrides basin to the east. It has a mean depth of about 2400 m with a maximum depth of 9140 m in the New Britain Trench. The shallowest parts are found on the continental shelf off of Queensland. See Rotschi and Lemasson (1967).

core layer method

A systematic attempt to apply hydrography to describe the waters of the ocean as developed by Wust and his students in the 1930s. In this method he distinguished between different core layers characterized by maxima or minima in their oxygen, salinity or temperature fields. While of unquestioned descriptive value, this method has some significant limitations. The number of layers that can be identified using this techique is limited, e.g. Wust identified just seven such layers in the North Atlantic, a shortcoming ameliorated by the development of the isopycnal method. Also, these layers were too often uncritically assumed to be the main paths of ocean circulation, an assumption that has been proven to be incorrect on more than one occasion.

Coriolis acceleration

An acceleration, the magnitude of which for a particle moving horizontally on the surface of the Earth is $2 \Omega V \sin \phi$ where $\Omega$ is the angular velocity of the rotation of the Earth, $V$ the vector velocity relative to the Earth's surface, and $\phi$ the latitude. This acceleration is directed perpendicular to the direction of $V$ and to the right (left) in the northern (southern) hemisphere. There are other terms for three-dimensional motion in GFD, but they are generally negligible.

Coriolis effect

The denotes the effect of the Coriolis force to deviate a moving body perpendicular to its velocity.

Coriolis force

The force which, acting on a given mass, produces the Coriolis acceleration. It is a fictitious force introduced to facilitate the application of Newton's second law of motion to a rotating reference frame.

Coriolis parameter

This is defined by

$$f\,=\,2 \Omega \sin \phi$$

where $\Omega$ is the angular velocity of the rotation of the Earth and $\phi$ the latitude. This gives the Coriolis acceleration on a moving particle when multiplied by that particle's velocity.

CORK

Acronym for Circulation Obviation Retrofit Kit, a device that allows boreholes to be isolated from the ocean water above the seabed and conditions in the hole to be monitored for long periods of time. CORK's purpose is to provide a long-term seafloor observatory intended to allow a monitored and accessible borehole to return to its pre-drilling state.

The CORK data logger can record temperature and pressure data for five years, and store it in memory for an additional five years until it can be retrieved via either a manned submersible or a ROV. The data is obtained by a string of sensors hanging from CORK at the bottom of the borehole. It also has fittings for recovering samples from inside the hole and allows fluid to be injected into the hole for certain kinds of tests.

[http://www-odp.tamu.edu/sciops/labs/downhole/cork.html]
[http://www-odp.tamu.edu/dsd/TOOLS/CORK.HTM]

COROAS

Acronym (in Portuguese) for Oceanic Circulation in the Western Region of the South Atlantic, a Brazilian research program whose objective was to determine the seasonal mean fields of velocity, heat and mass transport by the Brazil Current and the AAIW flowing into the coastal region of southeastern Brazil. The specific objectives included:

• estimating the baroclinic and barotropic components of the circulation along the Brazilian coast, including the continental shelf and shelf break regions, between Ubatuba and Cananéia;
• continuously monitoring the velocity field and heat and mass transports of the Brazil Current and AAIW along the southeastern Brazilian coast;
• determining the importance of mesoscale vortices to the heat and mass transport of the Brazil Current;
• determining the response of the continental shelf water to the forcing of intrusions by the Brazil Current and AAIW; and
• studying the deep circulation in the Brazil Basin, including its interaction with the Argentine Basin.

The experiment took place from November 1992 through February 1994.

[http://www.labmon.io.usp.br/projects/coroas/coroas.html]

CORSA

Acronym for Cloud and Ocean Remote Sensing around Africa, a project which aims to provide a quality controlled data set of surface, atmospheric and cloud parameters over a time period and at a resolution not available from any other source. The data are derived from NASA AVHRR GAC level 1b data products, with over 13,000 of these products having been processed. See the CORSA Web site.

COSNA

Acronym for Composite Observing System for the North Atlantic.

Costa Rica Coastal Current (CRCC)

A current found entirely in the eastern tropical Pacific. It begins just offshore of the Panama Bight where the North Equatorial Countercurrent (NECC) ends to the east of the Galapagos, and turns to the north off the coast of Central America and Mexico. It meets the southward flowing California Current around the mouth of the Gulf of California. The position of this confluence varies seasonally, with the meeting occurring off Tehuantepec during March and April, and off Baja California during September and October. After this confluence, it turns west to become part of the North Equatorial Current (NEC). The presence of this current is inferred mostly from large-scale hydrographic measurements. The northern part of this is sometimes called the Mexican Current.

During the winter months, strong winds cross Central America through several isthmuses, e.g. Tehuantepec and Papagayo. These disturb the Costa Rica Coastal Current by spinning up a wind jet across the shelf, and intense cooling of the sea surface beneath the jet results from the upwelling and entrainment of subsurface water. Large anticyclonic warm core eddies develop to the right (north) of the wind jet, along with weaker, short-lived cyclonic counter-eddies to its left (south). An average of five of the anticyclonic eddies are spun off each year. See Badan-Dangon (1998).

Costa Rica Dome

A region centered to the west of Central America around 8-10$^\circ$N and 88-90$^\circ$W and about 200 to 400 km wide. Open ocean upwelling causes a domelike configuration of the local well-defined thermocline, bringing nutrients to the photic zone and sustaining increased biological productivity. This cyclonic gyre is located between the North Equatorial Countercurrent (NECC) to the south, the Costa Rica Coastal Current (CRCC) to the east and north, and the extension of the California Current and beginnings of the North Equatorial Current (NEC) to the north and northwest. See Wyrtki (1964), Umutani and Yamagata (1991) and Badan-Dangon (1998).

cotidal line

Lines joining the points where high water occurs at the same time. The lines show the lapse of time between the moon's transit over a reference meridian (usually the Greenwich meridian) and the occurrence of high water for any point lying on the line.

coupled model

In climate modeling this refers to the combination of an atmospheric GCM with some sort of ocean model rather than the simple specification of SSTs as a lower boundary condition. From simple to complex, the ocean model hierarchy used proceeds from swamp ocean models to slab ocean or mixed-layer models to oceanic GCM models. See Meehl (1992) and Bye (1996).

Cox number

See McDougall et al. (1987).

CPOP

Abbreviation for complex principal oscillation pattern, a generalization of the POP concept into the complex domain. Although this was introduced to extend the POP technique to the modeling of standing wave oscillations, it was also found the CPOPs evolve more regularly and with less noise than POPs. Also, prediction skills are significantly stronger than with the POP model. See Burger (1993).

CPR

Abbreviation for continuous plankton recorder.

CREAMS

Acronym for Circulation Research of the East Asian Marginal Seas.

[http://hikari.riam.kyushu-u.ac.jp/creams.html]
[http://sam.ucsd.edu/onr_jes/onr_jes.html]

Cretan Intermediate Water (CIW)

A modified form of Levantine Intermediate Water (LIW) that enters the southern Aegean Sea as LIW via the eastern Cretan Straits and is ventilated and transformed by convective processes to become a slightly denser intermediate water mass. See Theocharis et al. (1999).

Cretan Sea

The southern part of the Aegean Sea, located between Crete to the south and the Cyclades to the north and centered around 25$^\circ$ E and 36$^\circ$ N. This has also been called the Sea of Crete and the Sea of Candia.

Cretan Sea Overflow Water (CSOW)

A designation proposed for a new deep water mass formed in the Cretan Sea. CSOW is warmer ($\theta$ $>$ 13.6$^\circ$C) and more saline (S $>$ 38.80) than Eastern Mediterranean Deep Water (EMDW). The formation of CSOW is an event of relatively recent origin, and is part of recent overall changes observed in the thermohaline circulation of the Eastern Mediterranean. The transition is mainly from a system with a single source of deep water in the Adriatic Sea (EMDW) to one with an additional source in the Aegean Sea (CSOW).

Other observed changes have been (according to Klein et al. (1999)):

All major water masses of the Eastern Mediterranean, including the Levantine Intermediate Water (LIW), have been strongly affected by the change. The stronger inflow intoxi the bottom layer caused by the discharge of CSOW into the Ionian and Levantine Basins induced compensatory flows further up in thexi water column, affecting the circulation at intermediate depth. In the northeastern Ionian Sea the saline intermediate layer consisting ofxi Levantine Intermediate Water and Cretan Intermediate Water (CIW) is found to be less pronounced. The layer thickness has been reduced by factor of about two, concurrently with a reduction of the maximum salinity, reducing advection of saline waters into the Adriatic. As a consequence, a salinity decrease is observed in the Adriatic Deep Water. Outside the Aegean the upwelling of mid-depth waters reaches depths shallow enough so that these waters are advected into the Aegean and form a mid-depth salinity-minimum layer. Notable changes have been found in the nutrient distributions. On the basin-scale the nutrient levels in the upper water column have been elevated by the uplifting of nutrient-rich deeper waters. Nutrient-rich water is now found closer to the euphotic zone than previously, which might induce enhanced biological activity. The observed salinity redistribution, i.e. decreasing values in the upper 500-1400 m and increasing values in the bottom layer, suggests that at least part of the transition is due to an internal redistribution of salt. An initiation of the event by a local enhancement of salinity in the Aegean through a strong change in the fresh water flux is conceivable and is supported by observations.

See Klein et al. (1999).

Cromwell Current

See Equatorial Undercurrent.

cryosphere

That part of the climate system consisting of the ice fields of Antarctica and Greenland, other continental snow and ice fields, sea ice and permafrost. At present the Antarctic ice sheet holds 89.3% of the total global ice mass, with the Greenland ice sheet holding 8.6% and mountain glaciers and permafrost holding 0.76% and 0.95%, respectively. The remaining 0.39% is distributed among seasonal snow and sea ice. See Untersteiner (1984), Hibler and Flato (1992), and Van der Veen (1992).

CRYSYS

Acronym for CRYospheric SYStem, a Canadian interdisciplinary science investigation under the NASA EOS program. The goals of CRYSYS are to develop capabilities for monitoring and understanding regional and North American variations in cryospheric variables, to develop and validate local, regional and global models of climate/cryospheric processes and dynamics, and the assemble, maintain and analyze key historical, operational and research cryospheric data sets. See the CRYSYS Web site.

C-SALT

Acronym for Caribbean-Sheets and Layers Transect, a combined mesocale, fine- and microstructure survey of the well-ordered thermohaline staircase in the tropical North Atlantic east of Barbados. Such staircases are thought to be the sites of enhanced vertical mixing by the salt finger form of double-diffusive convection. The C-SALT program was a coordinated attempt to measure the intensity of salt finger convection, monitor the finescale shear and density environment, establish the lateral extent of the layered structure, and collect velocity, hydrographic and tracer data needed to evaluate the role of the fingering processes in the regional evolution of water properties. The experiment was carried out in the spring and autumn of 1985 in an area centered at about 57$^\circ$W, 12$^\circ$N at the confluence of the high salinity Subtropical Underwater (SUW) at 150 m depth and the fresher Antarctic Intermediate Water (AAIW) at 750 m depth. The superposition of these two extrema gives rise to a strongly destabilizing vertical salinity gradient, i.e. the main determining factor for staircase formation.

The C-SALT program found a large, coherent, and long-lived thermohaline staircase in its study area. The occurrence of mixed layers at the minimum density ratio and the observed water mass transitions within layers indicate that salt fingers make a substantial contribution to both maintenance of the staircase and vertical mixing. See Schmitt et al. (1987).

CSCS

Abbreviation for Chukchi Sea Circulation Study.

CSEC

Abbreviation for Central South Equatorial Current.

CSR

Abbreviation for Cruise Summary Report. See ROSCOP.

CSW

Abbrevation for continental shelf wave.

CTD

In oceanography, an abbreviation for Conductivity-Temperature-Depth, an instrument for performing oceanographic measurements. The CTD measures (either directly or indirectly) the three most important oceanographic parameters for describing the distribution of water in the ocean: temperature, salinity, and pressure.

CTDO

Abbreviation for Conductivity-Temperature-Depth-Oxygen profiler.

CTW

Abbreviation for coastal trapped wave.

CTZP

Acronym for the Coastal Transition Zone Program, a research program that took place in 1987 and 1988 off the northern coast of California. The important questions this program attempted to address were the physical and biological nature and structure of cold filaments, what causes a filament to form, and the physical and biological characteristics of a filament. In order to address these questions the program included a modeling effort and divided the field effort into a pilot and a main program.

The pilot program took place in 1986-1987 and had the goals of gaining some three-dimensional information about biological, chemical, and turbulent processes in a filament as well as to gain further background information about the detailed physical structure. It included four large-scale, coarsely resolved surveys from San Francisco to northern California, taking place in both winter and summer. The goal was to see if filaments or related currents could be identified when upwelling was not present, thus confirming or denying the hypothesis that filaments are related to coastal upwelling.

The main program took place in summer 1988 and consisted primarily of a time series of repeated maps meant to chart out the time dependence of a single filament near Point Arena, California. It also allowed for well-sampled repeat sections of microstructure variability and detailed biological process measurements. The objective was to characterize the detailed temporal evolution of a filament and the processes that maintain its structure. See Brink and Cowles (1991).

CU

Abbreviation for California Undercurrent.

CUE

Acronym for Coastal Upwelling Experiment, an IDOE project.

CUEA

Acronym for Coastal Upwelling Ecosystems Analysis, an IDOE project. See Smith (1981) and Barber and Smith (1981).

cum sole

Descriptive of rotation in the same sense as a vector that points toward the sun, i.e. motion turning to the right (left) in the northern (southern) hemisphere, i.e. anticyclonic motion. This term, along with the opposite contra solem, was coined by V. W. Ekman in 1923.

curl

The curl of a vector field is a measure of its rotational motion, i.e. when applied to the velocity vectors of air or water motion, the curl is nonzero if the parcel is spinning. In mathematical terms, the divergence of a vector function is defined by

$$\nabla\times A$$

where $\nabla$ is the gradient operator that operates with a vector (or cross) product on the vector field $A$. See Dutton (1986).

current

A flow of water within the sea which is coherent at least in a time-averaged sense. The currents identified as such in the world ocean include: Agulhas Current, Agulhas Return Current, Alaska Coastal Current, Alaska Current, Aleutian Current, Algerian Current, Anadyr Current, Angola Current, Antarctic Circumpolar Current (ACC), Antilles Current, Azores Current, Baltic Current, Benguela Current, Bering Slope Current, Brazil Current, California Current, Canary Current, Caribbean Current, Central South Equatorial Current, Chile Current, China Coastal Current, Cromwell Current, Davidson Current, Davidson Inshore Current, Delware Coastal Current, East Australian Current, East Arabian Current, East Africa Coast Current, East Auckland Current, East Cape Current, East Greenland Current, East Icelandic Current, East Indian Current, East Korea Current, East Spitsbergen Current, Equatorial Countercurrent, Equatorial Intermediate Current, Falkland Current, Florida Current, Gaspe Current, Guineau Current, Guyana Current, Haida Current, Hopen-Bjornoya Current, Humboldt Current,

current meter

See Gould (2001) for a historical overview.

Current Meter Intercomparison Experiment (CMICE)

See Beardsley et al. (1981).

CW

Abbreviation for Central Water.

CWB

Abbreviation for Continental Water Boundary.

cyclone

An atmospheric pressure distribution in which there is a low central pressure relative to the surroundings. The circulation around the center is anticlockwise (clockwise) in the northern (southern) hemisphere.

cyclonic

The direction of rotation around a center of low pressure. This is counter-clockwise in the northern hemisphere and clockwise in the southern. The term originates from the circulation observed around tropical cyclones.

cyclosonde

A device that allows the profiling of the water column by alternately rising to the surface and sinking to a predetermined depth. It does so by adjusting its buoyancy. This device can be used as a platform for a variety of instruments. See Van Leer (1974).

cyclostrophic wind

A theoretically hypothesized wind that would exist, when blowing around circular isobars, as a balance between the pressure gradient and the centrifugal force. The Coriolis force is neglected, and as such this is a useful approximation only in low latitudes, e.g. in tropical cyclones.

CZCS

Abbreviation for Coastal Zone Color Scanner, a scanning radiometer with six spectral channels centered at 0.443, 0.520, 0.550, 0.670, 0.750 and 11.5 micrometers and selected to allow measurement of ocean color and temperature, suspended sediment and chlorophyll concentrations, and ocean pollutants. It works by measuring the ratio of different colors of visible light, with the basic idea being that the higher the concentration of chlorophyll-a in the water column, the greater the proportion of light in the peaks of its absorption spectrum that will be missing. This measurement is used as a proxy for the amount of phytoplankton primary production going on in the water column.

The CZCS sensor operates in the visible portion of the spectrum so it can only collect data in clear sky conditions. This leads to the necessity of taking multi-year averages over some areas, e.g. the Indian Ocean, to get useful images. The device resolution is 800 m. This instrument flew aboard the NIMBUS-7 satellite and was active between November 1978 and June 1986. Other ocean color sensors are being launched between 1996-1998, including NASA's SeaWiFs, NASDA's OCTS, and DLR's MOS.

The CZCS data is classified into various product levels depending on the processing of the data and what type of ancillary data is include. Level 0 data is the raw binary sensor counts recorded for radiation at 6 wavelengths. A Level 1 data product is the raw binary sensor counts cut into 2 minute scenes and bundled with orbital and atmospheric data. A Level 2 data product is a processed product where a sensitivity loss correction, atmospheric correction, and chlorophyll derivation algorithm have bee applied to a level 1 product to calculate surface reflectances, land/cloud flags, subsurface reflectances, atmospheric signals, and chlorophyll concentration.

A Level 3 Primary product is generated by remapping a number of level 2 products from the same day to a fixed geographical area, with the areas known as basins. This uses the orbital and geo-referencing data from the Level 1 product and applies a coastline feature matching algorithm. The basins are calculated in Alber's equal area projection with a 1 km pixel size. A Level 3 composite product is generated by calculating the average cholorophyll value for each pixel over a number of Level 3 Primary products. See the CZCS Dataset Guide Document.