Mn-Mz

MOBY

Acronym for Marine Optical Buoy, an instrument deployed off the coast of Lanai, Hawaii in Feb. 1994 to measure visible and near-infrared radiation entering and emanating from the ocean. The variations of the visible reflected radiation are referred to as the ocean color, a property from which other quantities such as the abundance of phytoplankton can be derived. MOBY will thus provide a time-series database for bio-optical algorithm development and the calibration of such satellite instruments as SeaWiFS, MODIS, and MERIS. See the MOBY Web site.

MOCE

Acronym for Marine Optical Characterization Experiment, a series of field experiments at different ocean sites to obtain a comprehensive set of bio-optical measurements such as radiometry, pigment analysis, total suspended matter, beam transmittance, and physical properties. See the MOCE Web site.

MOCNESS

Acronym for Multiple Opening Closing Net and Environmental Sampling System, a multiple net system used in biological oceanography to sequentially sample zooplankton at different depths or for collecting serial samples at the same depth. See Wiebe et al. (1976).

MODB

Abbreviation for Mediterranean Oceanic Data Base, a project to deliver advanced data projects for oceanographic research in the Mediterranean Sea. See the MODB Web site.

MODE

Acronym for the Mid-Ocean Dynamics Experiment, an program carried out between March and July 1973. The project explored - using different instruments to measure the same phenomena from dissimilar views - the role of mesoscale eddy motions in the dynamics of general oceanic circulation. MODE was also one of the first large-scale, extensively instrumented experiments performed by physical oceanographers. Henry Stommel was the chief motivating factor for MODE, the plans for which were solidified at a meeting at WHOI on July 20-24, 1970. Responsibility and authority for the experiment were in the hands of a 21 member MODE Scientific Council, with the membership consisting of the principal investigators from each of the experiments projects and representatives from the MODE Theoretical Panel. A six member Executive Committee additionally monitored the operation of the experiment. The principal source of funding was the NSF's Office for the Decade of International Ocean Exploration, with other sources including ONR, NOAA and the British NERC.

MODE was conducted in two phases between November 1971 and July 1973. The MODE-1 field program was carried out between March and July 1973. It was the culmination of a 16-month theoretical and observational field study known both as MODE-0 and PREMODE. It was a collection of 12 experimental and theoretical projects performed simultaneously, with the field program concentrated on a 600 square kilometer test site that extended from 28$^\circ$ N 69$^\circ$ 49' W, an area in the ocean between Bermuda and Florida. An important experimental component was the use of different instruments to measure the same phenomena from dissimilar views. It employed six ships, two aircraft, and new and sophisticated instruments such as neutrally buoyant floats, free fall velocity profilers, and air-dropped current probes. The design of the experiment relied heavily on objective mapping.

The experimental phase was followed by a two-month summer institute program at the University of Rhode Island in July and August of 1974, during which discussions with the ten-member Russian delegation led to the planning of POLYMODE. See McWilliams (1976a) and McWilliams (1976b).

[http://www.aip.org/history/ead/mit_mode/19990043_content.html]

Mode Water

A type of water created by property modification in the vicinity of ocean fronts, especially during winter. Convection creates a deep surface layer containing water of nearly uniform temperature and salinity in regions that usually feature strong horizontal and vertical gradients. A Mode Water core is defined by the existence of minima in vertical gradients. Commonly used properties are temperature and potential density anomaly, with the minimum gradient layer then being known as, respectively, a thermostad or pycnostad.

The mode water sinks along isopycnal surfaces, retaining its properties since they can only be changed by mixing with the surrounding water. Since deep mixing processes are much weaker at depth than near the surface, mode waters tend to retain their characteristics for great distances as they move around the ocean basins. Their persistent properties make them excellent tracers for climate change studies since they retain a record of surface conditions at the time of their formation.

There are two general varities of mode water: subtropical mode water and subpolar mode water. Types of subtropical mode waters include:

• Eighteen Degree Water
• North Pacific Subtropical Mode Water
• North Atlantic Subtropical Mode Water
• Madeira Mode Water

Types of Subpolar Mode Waters include:

• Subantarctic Mode Water
  • Antarctic Intermediate Water
  • Southeast Indian SAMW
• North Atlantic Subpolar Mode Water

See McCartney (1982) and McCartney and Talley (1982).

Modified Atlantic Water (MAW)

A water mass that originates as Atlantic Water (AW) entering the Mediterranean Sea via the Gibraltar Straits. It spreads via the Sicily Straits into the eastern Mediterranean as MAW in a layer confined to the upper 200 m. The Levantine Intermediate Water (LIW) flowing westward beneath it exits into the northern Atlantic where it constitutes the salty Mediterranean outflow water. MAW becomes progressively saltier along its route from the Sicily Straits to the Levantine basin, but exhibits little seasonality. See Perkins and Pistek (1990) and Malanotte-Rizzoli et al. (1997).

Modified Circumpolar Deep Water (MCDW)

A Southern Ocean water mass located below the Antarctic Surface Waters (ASW) and above the Antarctic Bottom Water (AABW). MCDW is differentiated from Circumpolar Deep Water (CDW) by being defined as colder and fresher than the regional CDW for a given density. Although the distinction between CDW and MCDW is admittedly fuzzy, it can be generally said that most of the CDW found in the open ocean will be unmodified, and that most on the shelf and slope will be modified. According to Whitworth et al. (1998), one could expect to find MCDW throughout the Antarctic slope region and anyplace else where upwelling causes enhanced entrainment into the surface layers, such as in the central dome of the Ross and Weddell gyres, or where local bathymetry produces upwelling, such as at Maud Rise in the Weddell Gyre.

Various other names have been applied to water masses now subsumed under MCDW. These include modified Circumpolar Water, slope water, Modified Warm Deep Water, anomalous water, Warm Core, Prydz Bay Bottom Water and Weddell-Scotia Confluence Water. See Whitworth et al. (1998) and Orsi et al. (1999).

Modified East Icelandic Water (MEIW)

A water mass comprising part of the Iceland-Faroe Ridge overflow. It acquires its main character in a region close to the ridge by the mixing of different water masses and sinking in the frontal zone. It is identified as a salinity minimum with salinities below 34.90 and temperatures usually around 2.-3$^\circ$C. It is considered to be a mixture of MNAW, NSAIW, EIW and NNAW. It can be seen forming a cold tongue along the Jan Mayen Front and then sinking and progressing southwards towards the Faroe Islands in between MNAW and NNAW. See Hansen and Osterhus (2000).

Modified Levantine Intermediate Water (MLIW)

A modified form of Levantine Intermediate Water (LIW) found in the Adriatic Sea. It has a temperature of 14$^\circ$C and a salinity of 38.7 psu. See Artegiani et al. (1993).

Modified Warm Deep Water (MWDW)

A type of water in the seas surround Antarctica that separates overlying Winter Water (WW) from underlying AACW.

MODIS

Abbreviation for Moderate-Resolution Imaging Spectroradiometer, an instrument built to fly on EOS AM-1 and that will view the entire Earth's surface every 1 to 2 days acquiring data in 36 spectral bands to improve our understanding of globa dynamics and processes occurring on the surface of the Earth, in the oceans, and in the lower atmosphere. See the MODIS Web site and King et al. (1992).

modon

To be completed.

Mohn, Henrik (1835-1916)

See Peterson et al. (1996), p. 100.

MOIST

Acronym for Moored Oceanographic Instrument SysTem.

Molucca Sea

One of the seas that comprise the Australasian Mediterranean Sea. It is centered at approximately 127$^\circ$ E and 2$^\circ$ N and is bordered by Sulawesi to the west, Halmahera to the east, the Sula Islands to the south, and Mindanao and the Pacific to the north. The approximately 200,000 sq. km area of this sea are underlain by a fairly complex series of troughs, basins and ridges that are usually divided into three north-south zones. The westernmost zone is the Sangir Trough connecting Davao Gulf in Mindanao with the Gorontalo Gulf; the central zone a broad ridge outlined by the 2000 m isobath which bears the Talaud and Miangas islands in the north; and the eastern zone a series of depressions and basins. This is also variously called the Maluku Sea.

The Molucca Sea is an important passageway for deep water flowing from the Pacific Ocean through the Australasian Mediterranean and on into the Indian Ocean. One branch of flow through the Molucca is composed of deep flow from the Pacific through the Sangir Trough and on into the Sulawesi Sea, while another branch has flow entering via the Morotai Basin and exiting via the Gorontalo Basin south of Sulawesia as well as through the Lifamatola Strait into the Banda and Ceram Seas. Surface salinities depart at most 0.3 from an annual average of 34.0, although higher salinities have been recorded late in the year in the north and southern extremities. The surface salinities range from 28.3$^\circ$ C in June to 27.0$^\circ$ C in January.

The monsoon winds drive the surface circulation, changing slowly in direction from northeast to north-northwest during the southern summer and generally reversing direction during the winter months. As such a slow current flows southwestward along the eastern margin of the sea along with an opposite (northward) flowing current of similar strength in the western half in the winter months. The northward flow is maintained throughout the year except in the northern reaches where an east-southeast directed current occurs in the summer months. See Fairbridge (1966) and Cresswell and Luick (2001b).

MOM

1. Acronym for Modular Ocean Model, a primitive equation general ocean circulation model developed at GFDL. It is intended to be a flexible tool for exploring ocean and coupled air-sea applications over a wide range of space and time scales. See the MOM Web site for further information. 2. Acronym for Musée Océanographie de Monaco.

Monaco Deep

See Canary Basin.

MONEX

Acronym for the summer and winter Asian Monsoon Experiments, a component of FGGE designed to study monsoonal circulations. See ().

monsoon

A periodic wind caused by the effects of differential heating, with the largest and most notorious being the Indian monsoon found in the Indian Ocean and southern Asia. The word is thought to have originated from the Arabic word mausim meaning season. See Webster et al. (1998).

[http://paos.colorado.edu/~webster/mw/jgrpaper/jgrmonsoon1.html]

Monterey Bay

See Breaker and Broenkow (1994).

Monterey Bay Aquarium Research Institute (MBARI)

A research institute established in 1987 with the goal of developing state-of-the-art equipment, instrumentation, systems, and methods of scientific research in the deep waters of the ocean. See the MBARI Web site.

Montgomery potential

A quantity defined as

$${M_o}\,=\alpha p\,+\,\phi$$

where $\alpha$ is the specific volume, $p$ the pressure, and $\phi$ the geopotential, i.e. $gz$. The Montgomery potential represents an exact stream function on specific volume anomaly surfaces. This is also known as the Montgomery stream function and the Bernoulli function in the geostrophic approximation.

Montgomery stream function

See Montgomery potential.

MOODS

Acronym for Master Oceanographic Observational Data Set. See Teague et al. (1987).

Moored Profiler (MP)

An instrument designed and built at WHOI to acquire repeated, high vertical resolution, full water column profiles of ocean currents and water properties at a fixed site. It does this by climbing up and down a fixed mooring via a traction system using a highly efficient electric motor, with battery capacity providing for over one million meters of vertical profiling. Data are stored on a hard disk during a deployment and and downloaded once the instrument is on deck. The MP can also return real-time data via satellite using inductive telemetry through the mooring cable. It is designed to carry a wide variety of sensors including a CTD and an acoustic phase-shift current meter (ACM). See the MP Web site.

MOOS

Acronym for MBARI Ocean Observing Systems, a research program to improve the understanding of the relationships between climatic variability, ocean circulation, marine chemistry, and phytoplankton biomass, composition and production with the use of moored platforms with unattended sensors, satellite imagery, and shipboard surveys. See the MOOS Web site.

MORENA

Acronym for the Multidisciplinary Oceanographic Research in the Eastern Boundary of the North Atlantic project, with the general objective of measuring, understanding, and modeling shelf-ocean exchange in a typical coastal upwelling region of the eastern boundary layer of the subtropical ocean. See the MORENA Web site.

Mornington Abyssal Plain

One of three plains that comprise the Pacific-Antarctic Basin (the others being the Amundsen and the Bellingshausen Abyssal Plains. It is located at around 85-95$^\circ$ W.

Mosely Deep

See Cape Verde Basin.

Mozambique Current

A western boundary current that flows south-southwestward between the African coast and Madagascar from about 10 to 35$^\circ$ S. The flow has been estimated at about 6 Sv near 15$^\circ$ S increasing to 15 Sv near 20$^\circ$ as the northward looping East Madagascar Current turns back towards the south and joins it. This combined flow eventually becomes the major part of the Agulhas Current.

MP

Abbreviation for Moored Profiler.

MSL

Abbreviation for Mean Sea Level.

MSP

Abbreviation for Multi-Scale Profiler, a dropsonde that resolves horizontal velocity over scales ranging from the ocean depth to microscale by combining electromagnetic, acoustic and hydrodynamic lift data on small airfoils. See Winkel et al. (1996).

MSR

Abbreviation for Microstructure Record, an instrument developed by the APL.

mss

Abbreviation for mean square sea slope, a quantity used to provide an estimate of the sea surface roughness for wind stress calculations. The directionally integrated mss of the sea surface is defined by

$${s^2}\,=\,{\int_{\infty}^\infty}{\int_{\infty}^\infty}\, {k^2}\psi(\mathbf{k})\,d\mathbf{k}$$

where $\psi(\mathbf{k})$ is the directional wavenumber and $\mathbf{k}$ the wavenumber vector. See Banner et al. (1999).

MSW

Abbreviation for Mediterranean Surface Water.

MTOC

Abbreviation for Monitoring Transport of Ocean Currents, a project of sorts.

MTP

An abbreviation for Mediterranean Targeted Project, a CEC/CGXII/MAST2 project engaged in oceanographic research activities in the Mediterranean Sea area during the period 1993-1996. It covers the disciplines of physics, chemistry, biology, geology, and biochemistry and involves approximately 180 scientists from 40 European instiutions and 14 countries. See the MTP Web site.

MTPR

Abbreviation for miniature temperature pressure recorder.

MUDAB

A project of the BSH operated by the DOD. It serves as the central German data base for marine data within the framework of international and national conventions for the protection of the North Sea and Baltic Sea. See the MUDAB Web site.

Multiple Current Hypothesis

A hypothesis advanced by Fuglister (1951) that the Gulf Stream system is irregular, varying and discontinuous east of the Grand Banks. The dearth of observations available in 1951 led him to suggest that an instantaneous chart, if available, would show a number of disconnected filaments of current rather than a continuous stream. This is an obvious foreshadowing of later developments predicated on more extensive theoretical and observational work that showed the instabilities to which the Gulf Stream is prone as it leaves the coast and heads east. It wanders and sheds eddies both north and south, processes that do indeed lead to the impression of a number of disconnected filaments. See also Stommel (1966).

Murray, John

More later.

MW

Abbreviation for Mediterranean Water.

MWDW

See Modified Warm Deep Water.

MWR

Abbreviation for Mixed Water Region, a name given to the region between the Kuroshio Extension and the Oyashio Front because it is a location where waters of subtropical, subpolar, and Sea of Japan origin meet and are transformed. This has also been referred to as the "perturbed area" by Kawai (1972). See Talley et al. (1995).