Ja-Jz

jackknife method

A statistical procedure in which, in its simplest form, estimates are formed of a parameter based on a set of N observations by deleting each observation in turn to obtain, in addition to the usual estimate base d on N observations, N estimates each based on N-1 observations. Combinations of these give estimates of both bias and variance valid under a wide range of parent distributions. This method has deposed distribution-based methods in many applications due to its simplicity, its applicability in complicated situations, and its lack of distributional assumptions, resulting in greater reliability in practice. An elementary review can be found in Efron and Gong (1983) and the extension of such methods to time series analysis (with several geophysical examples) is reviewed in Thomson and Chave (1991).

Jacobsen's method

A method suggested by Jacobsen (1927) to compute eddy coefficients using T-S diagrams. See Neumann and Pierson (1966).

JADE

See Fieux et al. (1994) and Molcard et al. (1994).

JAMRI

Acronym for Japan Maritime Research Institute.

JAMSTEC

Acronym for Japan Marine Science and Technology Center.

Jan Mayen Current (JMC)

An eastward flow emanating from the East Greenland Current (EGC) in the Greenland Sea. Its axis is north of Jan Mayen and centered on 72-74$^\circ$ N. Its position in the winter is often associated with an ice odden, a persistent eastward extension of the East Greenland Ice Stream. The upper layer baroclinic flow shows that about half of the JMC is a wide meander in the EGC and about half continues eastward to close the Greenland Gyre system on the south. Beneath the halocline the meander dissipates and the flow becomes more barotropic, with the barotropic flow steered to the east by the Jan Mayen Fracture Zone. This has also been called the Jan Mayen Polar Current. See van Aken (1995) and Bourke et al. (1992).

JAPACS

Acronym for Japanese Pacific Climate Study.

Japan Sea

A marginal sea of the western Pacific Ocean bounded on the east by the Japanese islands, the west and southwest by Korea, and the north and northwest by the former Soviet Union. It is connected to the East China Sea in the south, the Okhotsk Sea in the north, and the Pacific Ocean in the east via narrow passages whose sill depths don't exceed 100 m. It comprises the Japan Basin (with depths exceeding 3500 m) north of about 40$^\circ$ N, and the Yamato Basin (with depths around 2500 m) south of 40$^\circ$ N, the the basins separated by the Yamato Ridge. The dimensions are are about 1600 by 900 km, an area of 978,000 km$^2$, the average depth 1750 m, and a maximum depth of about 3700 m.

The Japan Sea is a meeting place for warm currents from the south and cold currents from the north, with the confluence being the Polar Front. Prominent circulation features in the Japan Sea include the Tshushima Current, the Tsugaru Current, the Liman Current, the North Korea Current and the Mid-Japan Sea or Maritime Province Current. Water masses found there include Japan Sea Middle Water (or Intermediate Water) and Japan Sea Proper Water.

The Tsushima Warm Current (TWC) transports warm, salty water into the sea through the Tsushima Strait. It either splits into three branches, takes a single meandering path, or takes both patterns alternately. In the contemporary literature, these branches are called (from east to west), the Nearshore Branch, the Offshore Branch and the East Korean Warm Current (EKWC). The Nearshore Branch flows eastward along the coast of Honshu and exits into the Pacific via the Tsugaru Strait. The more variable Offshore Branch flows along the continental shelf. The EKWC flows northward along the continental slope off the east coast of Korea up to about 37-38$^\circ$N, where it meets the southward flowing North Korea Cold Current (NKCC). At their confluence, the currents separate from the coast and flow east-northeast toward the Tsugaru Strait along the Polar Front. Most of the flow exists via the Strait, while the rest continues north as an eastern boundary current along the coast of Hokkaido called the Soya Warm Current (SWC). Some of the SWC flows into the Okhotsk Sea, while the rest flows southward along the Siberian coast as the Liman Cold Current (LCC) (or Primoriye Current) and (south of Vladivostok) as the NKCC. This forms a cyclonic gyre in the northern part of the basin. See Tomczak and Godfrey (1994), Zenkevitch (1963), Preller and Hogan (1998) and Chu et al. (2001).

Japan Sea Bottom Water (JSBW)

See Japan Sea Proper Water.

Japan Sea Deep Water (JSDW)

See Japan Sea Proper Water.

Japan Sea Middle Water (JSMW)

A water mass found in the Japan Sea. It is found in the depth range 25-200 m and characterized by a rapid drop in temperature from 17 to 2$^\circ$ C as well as an oxygen maximum of 8 ml/l near 200 m depth. The warmer layers are advected in by the Kuroshio and the colder layers formed by sinking at the Polar Front and on the shelf to the north.

Japan Sea Proper Water (JSPW)

A water mass in the Japan Sea that comprises all the water below 200 m (and thus the overlying Japan Sea Middle Water). It is characterized by uniform temperature (1-2$^\circ$ C) and salinity (34.1) which result from its isolation from other basins by shallow sills. It is formed via winter convection facilitated by the salt imported by the Tsushima Current, with the instabilities in the Polar Front serving to transport this salt into the northern formation regions. Some authors differentiate Japan Sea Deep Water (JSDW) (200 - 2000 m) and Japan Sea Bottom Water (JSBW) (2000 m - bottom), and occasionally the entire water mass is referred to as Japan Sea Deep Water. See Tomczak and Godfrey (1994) and Kawamura and Wu (1998).

Japan Stream

See Kuroshio Current.

JASADCP

Abbreviation for Joint Archive for Shipboard ADCP, a collaboration between the E. Firing ADCP Laboratoary at the University of Hawaii and the NODC. This center, formerly known as the Shipboard ADCP Center (SAC), is responsible for the acquisition, review, documentation, archiving, and distribution of shipboard ADCP data sets. It primarily handles U.S. national cruises, but also supports such multi-national programs as TOGA COARE, WEPOCS, and US-PRC cruises. The JASADCP is also a Data Assembly Center for WOCE in collaboration with the JODC.

[http://ilikai.soest.hawaii.edu/sadcp/]

JASIN

Acronym for the Joint Air-Sea Interaction experiment. See Nicholls et al. (1983) and Geernaert (1990).

JASMINE

Acronym for the Joint Air-Sea Monsoon INteraction Experiment, a cruise taking place in the east Indian Ocean and the Bay of Bengal between April 7 and June 8, 1999. The goal of JASMINE was to observe the atmosphere and ocean environment during a monsoon onset event, including both an active and break period, to understand the conditions responsible for the variability of the monsoon season on short time and space scales.

[http://paos.colorado.edu/~jasmine/]
[http://www.atmos.washington.edu/~serra/JASMINE/jasmine.html]

JavaSea

A shallow body of water located in the southwestern part of the Australasian Mediterranean Sea. Centered at about 114$^\circ$ E and 5$^\circ$ S, it has average depths of around 40-50 m, and an area ranging from 367,000 to 433,000 km$^2$ depending on where the boundaries are specified. It is connected to the Sulawesi Sea to the northeast by the Makassar Strait, adjoins the Flores Sea to the east, connects to the South China Sea to the northwest via the Karimata Strait, and abuts the Bali Sea to the south and Kalimantan to the north. It is sometimes grouped together with the shelf sector of the South China Sea as the SundaSea, and also variously spelled as Jawa Sea.

The Java Sea was formed when two large river systems, now forming shallow channels in the shallow sea floor, were drowned out at the end of the last ice age. The circulation and hydrography are determined by the annual cycle of monsoon winds, with currents flowing westward from June to August and eastward during the rest of the year. During this latter period a tongue of high salinity water from the South China Sea pushes salinity values of 32 as far east as 112$^\circ$ E. See Tomczak and Godfrey (1994).

Jawa Sea

See Java Sea.

JEBAR

In oceanography, an acronym for the Joint Effects of Baroclinicity And Relief, a term that arises from the derivation of the vertically integrated vorticity equation. See Huthnance (1984), Mertz and Wright (1992), Slordal and Weber (1996) and Cane et al. (1998).

JECSS

Acronym for Japan and East China Seas Study.

Jeffreys' theorem

A theorem that concerns the conditions under which hydrostatic equilibrium obtains. It states that hydrostatic equilibrium is impossible if density variaitons occur on level surfaces. See Hide (1978).

JENEX

Acronym for Japanese El Niño Experiment.

Jerlov water types

A scheme for classifying the optical properties of various waters based on their irradiance transmissivity in the upper 10 m. The scheme divides them into oceanic (Types I to III) and coastal (Types 1 to 9) categories. See Jerlov (1976).

jet stream

A well-defined core of strong wind, ranging from 200-300 miles (320-480 km) wide with wind speeds up to 200 mph (320 kph), that occurs in the vicinity of the tropopause. See Reiter (1963).

JGOFS

Acronym for Joint Global Ocean Flux Study, a subprogram of the IGBP whose goal is to improve our knowledge of the processes controlling carbon fluxes between the atmosphere, surface ocean, ocean interior and its continental margins, and the sensitivity of these fluxes to climate changes. JGOFS originated in Feb. 1987 when SCOR sponsored a meeting of experts in Paris where the goals, scientific elements, topics of emphasis, and organizational structure of JGOFS was established. An international planning Committee for JGOFS was established in Oct. 1987, which met for the first time in Jan. 1988.

The first JGOFS regional process study was the 1989 North Atlantic Pilot Study, which involved Germany, UK, Netherlands, USA and Canada. Soon after this, links were established with WOCE and TOGA. In 1989, an agreement between SCOR and ICSU established JGOFS as a core project of IGBP, although it would be responsible directly to SCOR.

[http://ads.smr.uib.no/jgofs/jgofs.htm]

JIC

Abbreviation for Joint Ice Center, a U.S. Navy/NOAA facility that produces sea ice analyses and forecasts on global, regional, and local scales. There are global analyses for both the northern and southern hemispheres with consist of a determination of the ice edge, the concentration of the ice, leads in the ice, and an estimation of the age of the ice. Regional ice analyses are produced twice per week for the Bering, Chuckchi and Beaufort Seas. Local scale analyses are available for ships operating in the Antarctic during the Austral summer. The JIC also produces 7- and 30-day ice forecasts as well as long-range outlooks. The 7-day forecasts are produced weekly for the eastern and western Arctic and give the expected position of the ice edge, while the 30-day forecasts are produced twice a month for the predicted ice edge position and ice concentrations in the eastern and western arctic. The long-range outlooks forecast the expected severity of ice conditions and are verified about 90 days after issuance. See ().

JIMAR

Acronym for Joint Institute for Marine and Atmospheric Research.

JISAO

Acronym for Joint Institute for the Study of the Atmosphere and Ocean.

JODC

Abbreviation for Japan Ocean Data Center, established in the Hydrographic Department of the Maritime Safety Agency in 1965 to fulfill the role of the marine data bank of Japan, acquiring marine data sets obtained by various research institutes and providing users with the data. See the JODC Web site.

JOI

Acronym for Joint Oceanographic Institutions, a consortium of U.S. academic institutions for organizing the collective capabilities of the individual oceanographic institutions on research planning and management of the ocean sciences. JOI was established as a private, non-profit organization in 1976.

[http://www.joi-odp.org/]

JOIDES

Acronym for Joint Oceanographic Institutions for Deep Earth Sampling, a program to obtain cores of deep ocean sediments.

[http://joides.rsmas.miami.edu/]

Joint Institute for Marine and Atmospheric Research (JIMAR)

A Joint Institute formed in 1977 between the University of Hawaii and the NOAA ERL. The purpose of JIMAR is to increase the effectiveness of oceanic, atmospheric, and geophysical research of mutual interest to NOAA and the University, with the principal research interests being equatorial oceanography, tsunamis, fisheries oceanography, and climate and global change. See the JIMAR Web site.

Joint Institute for the Study of the Atmosphere and the Ocean (JISAO)

A Joint Institute formed in 1980 between the University of Washington and the NOAA ERL. This was established in 1980 and has five core research areas: (1) climate variability; (2) global environmental chemistry; (3) estuaries; (4) recruitment of fish stock; and (5) policy, impact and response strategies with respect to climate variability. See the JISAO Web site.

Joint Skagerrak Expedition

An ICES sponsored 1966 program to further knowledge of the hydrography of the Skagerrak as a transition zone between the Baltic Sea and the North Sea. The expedition took place from June 20 to July 15, 1966 and involved Germany, Finland, Norway, the UK and Sweden. The particulars included:

• measurements of temperature, salinity, oxygen and phosphate - and in some cases pH and silicate - made at 21 sections covering 233 stations, most of which were repeated;
• current measurements made at 7 anchor sations, 8 drifting stations, and by 17 self-recording current meters laid out over periods of up to 20 days;
• about 100 vertical soundings of temperature and chlorinity (via bathysonde), temperature and salinity (via membrane salinometer), temperature (via bathythermograph) and transparency;
• continuous recordings of the surface layer temperature between 0 and 70 m via Delphin towing gear covering 36 profiles of nearly 1200 nm total length; and
• use of the vessels Skagerak, G. O. Sars and Meteor.

The data from the expedition were published in 1969 as ``Joint Skagerrak Expedition 1966'' Vols. 1-4 in the "ICES Oceanographic Data Lists" series, with the expedition atlas following as Vol. 5 in 1970.

[http://www.ices.dk/ocean/project/data/jskag66.htm]

JONSDAP

Acronym for Joint North Sea Data Acquisition Project, a cooperative data collection program begun in 1970 by the countries bordering the North Sea. The first phase of JONSDAP involved the systematic collection of data from moored stations and coastal observation sites in the North Sea from 1971 to 1973. The second phase, JONSDAP 73, was a program of tide and current measurement in the Southern Bight of the North Sea from September to October 1973. The third phase, JONSDAP 76, consisted of two intensive measurement programs:

• FLEX, the Fladen Ground Experiment to study the development of the thermocline and the dynamics of the plankton bloom; and
• INOUT, a program concerning the general circulation of the North Sea and the storm surge problem.

JONSIS

Acronym for Joint North Sea Information System.

JONSWAP

Acronym for JOint North Sea WAve Project. See Hasselmann et al. (1973).

JONSWAP spectrum

A wave spectrum developed for fetch-limited wind waves. This is basically the Pierson-Moskowitz spectrum multipled by an extra peak enhancement factor and fetch-dependent scale parameters. See Hasselmann et al. (1973).

JPOTS

Abbreviation for Joint Panel on Oceanographic Tables and Standards, a panel sponsored by UNESCO, ICES, IAPSO, and SCOR which first met in 1962 (in an earlier form not yet called JPOTS) to study and decide upon standards to measure the properties of sea water.

Jutland Current

See North Sea and Skagerrak.