BEAM FILLINGThe measure of variation of hydrometeor density throughout the radar sampling volume.
Beam RadiationSolar radiation that is not scattered by dust or water droplets.
BEAM WIDTHAngular width of antenna pattern. Usually that width where the power density is one-half that of the axis beam. (Half-Power or 3 dB point)
Bear's Cage[Slang], a region of storm-scale rotation, in a thunderstorm, which is wrapped in heavy precipitation.
Bear-trap gateAny of a family of crest gates consisting of two leaves, an upstream leaf hinged and sealed at the upstream edge and a downstream leaf hinged and sealed…
Bearing WallA wall that carries ceiling rafters or roof trusses.
Beaufort ScaleThe Beaufort wind scale is a system used to estimate and report wind speeds when no measuring apparatus is available.
Beaver('s) Tail[Slang], a particular type of inflow band with a relatively broad, flat appearance suggestive of a beaver's tail.
becquerelThe special name for the unit that expresses a measure of activity. One becquerel corresponds to one disintegration per second of any radionuclide.
Bed elevationHeight of streambed above a specified level.
Bed layerThe flow layer, several grain diameters thick (usually taken as two grain diameters thick), immediately above the bed.
Bed LoadSediment that moves by rolling or sliding along the bed and is essentially in contact with the streambed in the bed layer.
Bed materialUnconsolidated material, or sediment mixture, of which a streambed is composed.
Bed-load dischargeThe quantity of bed load passing a cross section of a stream in a unit of time.
Bed-material dischargeThat part of the total sediment discharge which is composed of grain sizes found in the bed.
BeddingIn fishing, this term refers to bedding fish during the spawning period.
Bedding planeA separation or weakness between two layers of rock, caused by changes during the building up of the rock-forming material.
BedloadCoarse sediments carried along near the bottom of a river.
BedrockGeneral term referring to the solid rock or ledge underlying other unconsolidated material, i.e., soil, loose gravel, etc.
beerA fermented broth that consists of water, ethanol, and small amounts of ether and assorted alcohols.
Beginning of FreezupDate on which ice forming a stable winter ice cover is first observed on the water surface.
Beginning of the BreakupDate of definite breaking, movement, or melting of ice cover or significant rise of water level.
BellAn expanded, or enlarged, end of a pipe section, into which the next pipe fits. See spigot.
BenchThe seat occupied by the judge. More broadly, the court itself.
Bench mark (BM)A permanent or temporary monument of known elevation above sea level, used for vertical control at a construction site.
bench-scale processA small- or laboratory-scale process; commonly used in connection with fermentation.
BenchmarkA standard unit used as the basis of comparison; a universal unit that is identified with sufficient detail so that other similar classifications can be…
Benchmark (BM)A permanent point whose known elevation is tied to a national network. These points are created to serve as a point of reference.
Beneficial useWater loss through use for the betterment of society, e.g. irrigation or municipal use. See consumptive use.
Beneficial use of waterA use of water resulting in appreciable gain or benefit to the user, consistent with state law, which varies from one state to another.
BeneficiaryA person who is entitled to receive the benefits or proceeds of a will, trust, insurance policy, retirement plan, annuity, or other contract.
Benefit-cost ratio (B/C)The ratio of the present value of project benefits to the present value of the project costs, used in economic analysis.
Benefits ChargeThe addition of a per unit tax on sales of electricity, with the revenue generated used for or to encourage investments in energy efficiency measures…
BenthicOccurring at or near the bottom of a body of water.
benthic foraminiferasingle-celled animals that live near the sediment water interface and have calcium carbonate skeletons.
BenthosOrganisms living in or on the bottom of a lake, pond, ocean, stream, etc.
Bentonitic clay (bentonite)A clay with a high content of the mineral montmorillonite, usually characterized by high swelling on wetting and shrinkage on drying.
benzeneA chemical that is used widely by the chemical industry, and is also found in tobacco smoke, vehicle emissions, and gasoline fumes.
Bergeron ProcessThe process by which ice crystals in a cloud grow at the expense of supercooled liquid water droplets.
Bergy BitA piece of ice which has broken away from an iceberg, extending 1-5 meters above the sea surface and 100-300 square meters in area.
Berlin MandateA ruling negotiated at the first Conference of the Parties (COP 1), which took place in March, 1995, concluding that the present commitments under the…
BermA horizontal strip or shelf built into an embankment or cut to break the continuity of the slope, usually for the purpose of reducing erosion or to…
Bermuda HighA semi-permanent, subtropical area of high pressure in the North Atlantic Ocean off the East Coast of North America that migrates east and west with…
Best available control measuresThe most effective measures for controlling small or dispersed particulates from sources such as soot and ash from woodstoves and open burning of brush…
Best available control technology (BACT)That combination of production processes, methods, systems, and techniques that will result in the lowest achievable level of emissions of air pollutants…
Best gateThe gate opening where the peak efficiency of a turbine occurs at a particular head.
Best Management Practice (BMP)A practice or combination of practices that are determined to provide the most effective, environmentally sound, and economically feasible means of…
Best management practices (BMP)A practice or combination of practices that a designated agency determines to be the most effective, practical means of reducing the amount of pollution…
Best TrackA subjectively-smoothed representation of a tropical cyclone's location and intensity over its lifetime.
beta particleA high-speed electron or positron, emitted in radioactive decay.
Beta particle (beta radiation, beta ray)An electron of either positive charge (ß+) or negative charge (ß-), which has been emitted by an atomic nucleus or neutron in the process of a…
beta-DNAThe normal form of DNA found in biological systems, which exists as a right-handed helix.
beta-galactosidaseA bacterial enzyme that catalyses the cleavage of lactose into glucose and galactose, commonly used as a marker in DNA cloning.
beta-glucuronidase(Abbreviation: GUS). An enzyme produced by certain bacteria, which catalyses the cleavage of a whole range of beta-glucuronides.
beta-LactamaseAmpicillin resistance gene. (See Selectable marker.)
bias(BY-us) In a scientific research study or clinical trial, a flaw in the study design or the method of collecting or interpreting information.
Bid-ask differential, or spreadThe difference in price between what a buyer offers to pay for a commodity and what a seller offers to accept for a commodity, sometimes referred to as…
BiennialA plant which completes its life cycle within two years and then dies.
BifaceA stone tool that has been flaked on both sides.
Big BangThe scientific theory of the origin of the universe as an explosion of space and matter, starting from an enormously dense and hot state at some finite…
Big gameThose species of large mammals normally managed as a sport-hunting resource.
Bilateral transactionA direct contract between a seller and buyer outside of a centralized market or exchange (e.g. Nymex or an RTO/ISO).
Billing creditIn the Pacific Northwest, a payment by the Bonneville Power Administration to a wholesale customer for actions taken by that customer to reduce BPA´s…
Billow CloudA cloud consisting of broad parallel bands oriented perpendicular to the wind.
BimetalTwo metals of different coefficients of expansion welded together so that the piece will bend in one direction when heated, and in the other when cooled…
Bin MethodA method of predicting heating and/or cooling loads using instantaneous load calculation at different outdoor dry-bulb temperatures, and multiplying the…
Binary CycleCombination of two power plant turbine cycles utilizing two different working fluids for power production.
binary vector systemA two plasmid system in Agrobacterium tumefaciens designed to transfer T-DNA into plant cells, while avoiding the formation of crown gall tumours.
Binder (soil binder)Portion of soil passing a No. 40 (0.425 mm) United States Standard sieve.
bindingThe ability of molecules to bind each other non-covalently because of the exact shape and chemical nature of parts of their surfaces.
BinomialScientific name of plants or animals which has two parts: a genus and a species name.
bio-A prefix used in scientific words to associate the concept of "living organisms.
bio-accumulationA problem that can arise when a stable chemical such as a heavy metal or DDT is introduced into a natural environment.
bio-assay1. The assessment of a substance's activity on living cells or on organisms. Animals have been used extensively in drug research in bio-assays in the…
bio-augmentationIncreasing the activity of bacteria that decompose pollutants; a technique used in bioremediation.
bio-energeticsThe study of the flow and the transformation of energy that occur in living organisms.
bio-engineeringThe use of artificial tissues, organs and organ components to replace parts of the body that are damaged, lost or malfunctioning.
bio-enrichmentAdding nutrients or oxygen to increase microbial breakdown of pollutants.
bio-ethicsThe branch of ethics that deals with the life sciences and their potential impact on society.
bio-informaticsThe use and organization of information of biological interest. In particular, concerned with organizing bio-molecular databases (particularly DNA…
BioaccumulantsSubstances in contaminated air, water, or food that increase in concentration in living organisms exposed to them because the substances are very slowly…