Wa-Wm

 

wadi

A dry stream bed. This term, of Arabic origin, has also been spelled as ``ouadi''.

 

WADIC

Acronym for Wave Direction Measurement Calibration Project, a program held in the vicinity of the Edda platform in the Ekofisk field in the North Sea during winter 1985-1986. Several wave buoys, platforms and wave staffs were intercalibrated in this project. See Allender et al. (1989).

 

WAGS

Acronym for World Atmosphere Gravity Wave study. See Williams et al. (1988).

 

WAIS

Acronym for the West Antarctic Ice Sheet initiative, a nultidisciplinary study of rapid cliate change and future sea level. The goal of the project is to answer the fundamental climate questions of how the potentially unstable West Antarctic ice sheet might affect future sea level and how rapid global climate changes occur. See the WAIS Web site.

 

Walker circulation

A name coined by Bjerknes for two circulation cells in the equatorial atmosphere, one over the Pacific and one over the Indian Ocean. Schematically these are longitudinal cells where, on one side of the ocean, convection and the associated release of latent heat in the air above lifts isobaric surfaces upward in the upper troposphere and creates a high pressure region there. The lack or lesser degree of the same process on the other side of the ocean results in lower pressure there, and a longitudinal pressure gradient is established which, being on the equator, cannot be balanced by the Coriolis force. Thus a direct zonal circulation is driven in the equatorial plane with countervailing winds at the surface and in the upper troposphere, with concomitant rising and sinking branches on the appropriate sides of the ocean.

The normal Walker circulation in the Pacific consists of air rising over Indonesia, west winds in the upper troposphere, sinking air off the west coast of South America, and east winds near the surface. A reversed but weaker Walker circulation (and an enhanced Hadley circulation occurs during ENSO years. In the Indian ocean the circulation cell proceeds in the opposite sense (to the normal Pacific Walker cell), with sinking air over cold waters off the Somali coast and a low-level acceleration from west to east along the equator in the lower atmosphere. See Henderson-Sellers and Robinson (1986) and Kraus and Businger (1994).

 

Walvis Basin

See Cape Basin.

 

WAMDI

Acronym for Wave Model Development and Implementation group, an organization created to advanced sea surface state models. See Group (1988).

 

WAMEX

Acronym for the West African Monsoon Experiment, a component of FGGE designed to study monsoonal circulations.

 

Warm Deep Water

See Antarctic Circumpolar Water.

 

Warthe-Weischel

The American name for the glacial period that started 110,000 years ago and lasted 100,000 years. It featured extensive ice cover in North America and Northern and Central Europe, most of which disappeared during a warm interstadial. There were also three stadials during this period, which is called the Wurm period in the Alpine system and the Wisconsin period in the Scandinavian system. The was preceded by the Saale period.

 

WAT-BEE

Acronym for WOCE/Atlantic/Tropical-Boundary Eastern Equatorial.

 

water mass

In physical oceanography, a body of water with a common formation history. A water mass is identified through relationships on a T-S diagram, although additional information about the degree of spatial and temporal variability during its formation as expressed by a standard deviation is almost always needed as well. A single T-S point, i.e. a water type, along with its standard deviation, may be sufficient for identification (especially with deep water masses), although generally a set of T-S combinations, i.e. a function in T-S space, is needed along with a standard deviation envelope. Generally the standard deviation decreases with depth. In practice not enough data is usually available to calculate a standard deviation, so a point or line in T-S space is specified around which the water mass properties are presumed to vary.

Examples include AAIW, AASW, SAMW, SAUW, AACW, WDW, AABW, ABW, GSDW, ASW, PDW, SIW, WSPCW, ESPCW, WNPCW, ENPCW, NPEW, SPEW, JSMW, JSPW, IDW, PGW, ICW, AAMW, BBW, LSW, EMW, AIW, SACW, NACW, MMW, MDW, AW, and LIW.

 

water mass characteristics

A property value or, more often, range of property values by which a water mass can be identified and tracked through the ocean. The most commonly used are temperature, potential temperature, salinity, potential density or the density referenced to a particular depth or pressure. Less often used by still quite valuable for certain applications are oxygen, nitrate, phosphate, silicate, chlorofluorocarbon, carbon 14 and tritium. See also the entry on ocean tracers.

 

water type

In physical oceanography, a point on a T-S diagram.

 

water vapor feedback

A positive feedback loop in the atmosphere wherein an increase in temperature increases the water holding capacity. This will lead to an increase in the amount of atmospheric water vapor which, being a greenhouse gas, will in turn lead to another temperature increase. This process is better understood in the lower troposphere where there is reasonable certainty as to the feedback process. The upper atmosphere, while not as well understood in this regard, has a preponderance of evidence pointing to this. The temperature change is not uniform with height and the resulting changes in the vertical temperature gradient can partially compensate for the water vapor feedback.

 

water vapor mixing ratio

The ratio of the mass of water vapor to the mass of dry air in a specified volume as expressed in grams per kilogram.

 

water vapor pressure

The part of atmospheric pressure due to the water vapor in the atmosphere.

 

WATOX

Acronym for Western Atlantic Ocean Experiment.

 

WATTS

Acronym for Western Atlantic Thermohaline Transport Study.

 

waveband

A band or range of continously contiguous frequencies in a given larger range.

 

wave climate

The general condition of sea state at a particular location, the principal elements of which are the wave height, period parameters, and the wave direction. The significant wave height is usually used as the heighter parameter with the period parameter either the significant wave period as determined from time-series analysis, the period corresponding to the spectral peak frequency, or the mean wave period from time-series or spectral analysis. The wave direction is usually expressed with the 16-point bearing system (i.e. NNE, WSW, etc.). The wave climate is described in terms of months, seasons and years. See Goda (1990).

 

wave forecasting

Predicting the development and characteristics of ocean surface gravity waves via semiempirical methods. These methods use some theory in their foundation but require basic data for the evaluation of various constants and coefficients. Advances in the state-of-the-art are usually a matter of collecting a larger database of winds and the wave they generate. The two main approaches to wave forecasting are the significant wave method and the wave spectrum method. See Komar (1976).

 

wave set-down

See wave set-up.

 

wave set-up

A phenomenon local to the surf zone wherein wave breaking causes a stress or a landward push of the water which causes it to pile up against the shore until the seaward slope of this set-up is sufficient to oppose the wave stresses. This is called wave set-up to distinguish it from storm set-up or storm surge and from wind set-up, both of which occur over a larger scale. Wave set-up can range from 17-50% of the incident wave height on natural beaches which can give values of up to 1 m during large storms, which can result in a shoreward indundation of 50 m on a beach with a 1:50 slope. A related wave set-down is found in the vicinity of the wave breaking point in the surf zone, while the set-up occurs shoreward of this. of the wave breaking point on the beach profile, with a small set-down also found at The mechanism by which waves can exert a stress on the fluid in which they propagate is via a phenomenon called radiation stress. See Holman (1990).

 

wave spectrum method

A method of wave forecasting that describes the waves generated by storms in terms of a complete spectrum of periods and energies rather than in terms of a single significant wave height or period. An example of a wave spectrum method is the P-N-J method, while a significant wave method is the S-M-B method. See Komar (1976).

 

WBC

Abbreviation for western boundary current.

 

WBGU

Abbreviation for Wissenschaftlicher Beirat Globale Umweltveranderungen or, in translation, the German Advisory Council on Global Change. The objectives of this council are to evaluate scientific knowledge concerning all aspects of global environmental change in the interdisciplinary context of the Earth system, and to formulate recommendations for political action on the basis of this knowledge. See the WBGU Web site.

 

WCASP

Abbreviation for the World Climate Applications and Services Program, a major component of the WMO-coordinated WCP. See the WCASP Web site.

 

WCCRP

Abbreviation for Wyrtki Center for Climate Research and Prediction.

 

WCDMP

Abbreviation for World Climate Data and Monitoring Program.

 

WCIRP

Abbreviation for the World Climate Impact Assessment and Response Strategies Program, a major component of the WMO-coordinated WCP. This program is the responsibility of UNEP.

 

WCMC

Abbreviation for World Conservation Monitoring Center.

 

WCP

Abbreviation for World Climate Program.

 

WCRP

Abbreviation for World Climate Research Program.

 

WDC

Abbreviation for World Data Center, a system of facilities established within the framework of the IOC IODE program to receive oceanographic data and inventories from NODCs, RNODCs, marine science organizations, and individual scientists. The data are collected and submitted voluntarily from national programs or arise from international cooperative ventures. The WDCs are also responsbile for monitoring the performance of the international data exchange system. See the See the IODE Web site.

 

WDW

See Warm Deep Water.

 

Weak Sun Paradox

See Faint Young Sun Paradox.

 

weather

That which everybody talks about but nobody does anything about. The weather, as distinguished from the climate, consists of the large fluctuations in the atmosphere from hour-to-hour or day-to-day. These occur as weather systems move, develop, evolve, mature and decay as forms of atmospheric turbulence. Weather systems originate mainly from atmospheric instabilities and their evolution is nonlinear, making them unpredictable beyond a week or two into the future. They most likely never will be predictable beyond that due to the inherent properties of systems governed by chaotic dynamics. See Houghton and Filho (1995).

 

Weber number

A dimensionless number that relates the inertial force to the surface tension force. It is given by

where is the kinematic viscosity, l a characteristic length scale, the fluid density and the surface tension.

 

Weddell Gyre

See Deacon (1979).

 

Weddell Gyre Boundary

See Continental Water Boundary.

 

Weddell Sea

More about which later.

 

Weddell-Scotia Confluence

The zone separating the waters of the Weddell Sea from those of the Scotia Sea in the Southern Ocean. This is a line extending from the South Shetland Islands near the Antarctic Peninsula in a northeastward direction across the southern Scotia Sea to as far as 30 E. The deep waters on either side of the boundary are distinguishable on the basis of their temperature and salinity properties, with those to the north of the line (from the southeast Pacific) being warmer and slightly saltier.

The water column in the western WSC itself is nearly homogenuous due to vertical mixing that is active to one degree or another throughout the year. As one proceeds eastward lateral mixing processes gradually mix this homogenous water with the stratified waters to the north and south until such stratification is restored on the WSC is no longer in evidence. The complex bathymetry in the region is thought to play a major part in inducing the lateral mixing processes. See Patterson and Sievers (1980).

 

Weddell Sea Bottom Water (WSBW)

A type of water found in the seas surrounding Antarctica with temperatures ranging from -1.4 to 0.8 C and salinities of 34.65 ppt. It underlies Antarctic Bottom Water (AABW) and is found on the slopes and southern and western ages of the Weddell Sea basin.

 

Weddell Deep Water (WDW)

In physical oceanography, a water mass type formed in the Weddell Sea by surface cooling and subsequent convection in the polyna. This water has stable properties with a potential temperature between 0.4-0.7 C. WDW mixes with water above the continental slope in the Weddell Sea to serve as one source for Antarctic Bottom Water. See Gordon (1982) and Tomczak and Godfrey (1994).

 

well mixed estuary

One of four principal types of estuaries as distinguished by prevailing flow conditions. In this type the water column is (as you might have guessed) well mixed with essentially no variation in salinity in a vertical column. The Thames estuary is an example of this type.

 

WEPOCS

Acronym for Western Equatorial Pacific Ocean Circulation Study. See Lindstrom et al. (1987).

 

WEPOLEX

Acronym for the U.S.-U.S.S.R. Weddell Polynya Expedition of 1981 aboard the Soviet icebreaker SOMOV.

 

West African Trough

See Guinea Basin.

 

West Europe Basin

An ocean basin located in the eastern North Atlantic Ocean off the west coast of Europe (and also called the Northeastern Atlantic Basin). This includes the Porcupine Abyssal Plain west of Britain, the Biscay Abyssal Plain, and is connected to the Iberia Basin to the south by the Theta Gap. See Fairbridge (1966).

 

West Spitsbergen Current

See Swift (1986) and Pfirman et al. (1994).

 

western boundary current (WBC)

The intensification of the western limb of an oceanic circulation gyre. This is inevitable given a rotating earth, a meridional boundary, and a zonal wind stress pattern that reverses direction at some latitude as was shown using a simple dynamical model in the classic paper of Stommel (1948). Common features of such currents include their flowing as swift narrow streams along the western continental rise of ocean basins, their extension to great depth well below the thermocline, and their separation from the coast at some point and continuation into the open ocean as narrow jets that develop instabilities along their paths. The most well-known western boundary currents are the Gulf Stream and the Kuroshio Current. See Hogg and Johns (1995).

 

Western Mediterranean Circulation Experiment (WMCE)

A program to study the circulation of the western Mediterranean Sea from the Strait of Sicily to the Strait of Gibraltar using scales ranging from basin size to 1 km and depths from the surface to the deepest layers. The specific goals were to study the major features of the circulation and their variation in space and time, the physical forcing mechanisms, the affects of the circulation on the chemical, biological and optical properties of the western Mediterranean, and to implement the knowledge gained into numerical models.

The field study began in November 1985 and ended in March 1987, and consisted of the placement of long-term current meter moorings as well as campaigns for procuring measurements from aircraft. The field campaigns ran concurrently with those of two other experiments: POEM and the Gibraltar Experiment, with some effort being expended to make the three campaigns complementary to each other. See La Violette (1990).

 

Western Mediterranean Deep Water (WMDW)

See Perkins and Pistek (1990).

 

Western North Pacific Central Water (WNPCW)

In physical oceanography, the dominant water mass in the northern subtropical gyre, formed and subducted in the northern STC. This is fresher than NPEW at all temperatures and saltier than ENPCW except at temperatures above about 17 C (the upper thermocline). It is separated to the east from ENPCW at around 170 W and to the south from NPEW at around 12-15 N. See Tomczak and Godfrey (1994), p. 165.

 

Western South Pacific Central Water (WSPCW)

In physical oceanography, a water mass which is one of six distinguishable Central Water masses in the Pacific Ocean. Its T-S properties are almost indistinguishable from those of ICW and SACW, indicative of similar atmospheric conditions during formation. It is formed and subducted in the STC between Tasmania and New Zealand, and is geographically restricted by that and Australia at 150 W. It is separated to the east from the fresher ESPCW in a broad transition zone between 145 and 100 W, and to the north from SPEW, fresher above 8 C and saltier below, at around 15 S. See Tomczak and Godfrey (1994), p. 164.

 

WESTRAX

Acronym for WEStern TRopical Atlantic eXperiment. See Brown et al. (1992).

 

wet-bulb temperature

The temperature obtained by covering the bulb of a dry-bulb thermometer with a silk or cotton wick saturated with distilled water and drawing air over it at a velocity not less than 1000 ft/min. This is often accomplished by swinging the covered thermometer on the end of a string or rope. If the atmosphere is saturated with water vapor, the water in the wick will not evaporate and the dry and wet bulb temperatures will be the same. If the atmosphere is not completely saturated, the water will evaporate from the wick at a rate depedent upon the degree of saturation. The evaporation will cool the bulb and lower the temperature reading over that of the dry-bulb temperature to that of the wet-bulb temperature.

 

WGNE

Abbreviation for Working Group on Numerical Experimentation.

 

white noise

Noise that results in a spectrum where all frequency components have the same amount of energy. This can also refer the the resulting spectrum as well as the process. Compare to red noise.

 

White Sea

One of the seas found on the Siberian shelf in the Arctic Mediterranean Sea. It is located to the west of the Barents Sea and is otherwise landlocked. See Zenkevitch (1963).

 

WHOI

Abbreviation for Woods Hole Oceanographic Institution.

 

WHP

Abbreviation for WOCE Hydrographic Program Office. See the WOCE entry.

 

WHYCOS

Acronym for World Hydrological Cycle Observing System.

 

Wien displacement law

In radiation transfer, a law stating that the wavelength of maximum emission for a body at a particular temperature is inversely proportional to the temperature and is given by

where T is the temperature (K). The temperature of a black body can be determined from the wavelength of maximum monochromatic radiation using this relation. The maximum emission wavelengths for the Sun and the Earth calculated from this are, respectively, 0.50 m and 11.4 m.

 

Wilkes, Charles (1798-1877)

See Peterson et al. (1996), p. 72.

 

williwaw

A violent squall in the Straits of Magellan. This is a region where the winds are almost constantly strong and westerly.

 

WINCE

Acronym for Winter Cloud Experiment.

 

wind chill temperature

The hypothetical air temperature in calm conditions that would cause the same heat flux from the skin as occurs for the true winds and the true air temperature.

 

WINDII

Acronym for Wind Imaging Interferometer, a satellite-borne instrument the provides direct observations of wind velocity through measurements of the Doppler shifts of selected emission and absorption lines. The shifts are measured in two directions, yielding two components of the wind velocity relative to the spacecraft. The true winds can then be calculated from the observing geometry and the spacecraft velocity. The instrument consists of a telescope, a high resolution Michelson interferometer, and a detector array. The telescope views 45 and 135 from the spacecraft simultaneously and the detector provides a vertical resolution of about 4 km as well as a horizontal resolution of about 20 km. It is accurate to within 10 m/s in the altitude range 80 to 300 km. See the WINDII Web site.

 

Winter Intermediate Water (WIW)

See Perkins and Pistek (1990).

 

Winter Water

See Subantarctic Mode Water.

 

Winter Weddell Sea Experiment

An experiment taking place in 1986.

 

Wisconsin

The Scandinavian name for the Warthe-Weischel glacial period.

 

Wisconsin school

In phytosociology, a school based on the individualistic concept of the plant association. This school is known for its pioneering use of ordination methods. See Bray and Curtis (1957) and Collinson (1988).

 

WISP

Acronym for Winter Icing and Storms Project, a NOAA ETL project to study the meteorological conditions that produce hazardous aircraft icing conditions in winter storms, which entails forecasting and detecting regions of supercooled liquid water in the storms. See the WISP Web site.

 

WIW

Abbreviation for Winter Intermediate Water.

 

WKB approximation

More later.

 

WMCE

Abbreviation for Western Mediterranean Circulation Experiment.

 

WMDW

Abbreviation for Western Mediterranean Deep Water.

 

WMO

See World Meteorological Organization.

 

WMOSA

Abbreviation for WMO Satellite Activities, the purpose of which is to coordinate environmental satellite matters and activities throughout all WMO programs and to advise on the potentialities of remote-sensing techniques. See the WMOSA Web site for further information.