BarographA barometer that records its observations continuously.
BarometerAn instrument that measures atmospheric pressure.
Barometric PressureThe pressure of the atmosphere as indicated by a barometer.
Barotropic SystemA weather system in which temperature and pressure surfaces are coincident, i.e.
BarotropyThe state of a fluid in which surfaces of constant density (or temperature) are coincident with surfaces of constant pressure; it is the state of zero…
Barr bodyA condensed mass of chromatin found in the nuclei of female mammals. It is a late-replicating, inactive X-chromosome. See: dosage compensation, sex linkage
BarrageAny artificial obstruction placed in water to increase water level or divert it. Usually the idea is to control peak flow for later release.
Barrage (gate-structure dam)A barrier built across a river, comprising a series of gates which when fully open allow the flood to pass without appreciably increasing the flood level…
BarrelA volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons.
barrel (of oil)A liquid measure equal to 42 U.S. gallons, or typically about 306 lb of oil. One barrel equals 5.6 ft3; for crude oil, one barrel contains about 5.
Barrel (petroleum)42 U.S. gallons (306 pounds of oil, or 5.78 million Btu).
Barrel of oil equivalentA unit of energy equal to the amount of energy contained in a barrel of crude oil. Approximately 5.78 million Btu or 1,700 kWh.
Barrier JetA jet-like wind current that forms when a stably-stratified low-level airflow approaches a mountain barrier and turns to the left to blow parallel to the…
Bartel's Rotation NumberThe serial number assigned to 27-day rotation periods of solar and geophysical parameters.
BaryonSubatomic particles comprised of three quarks. Protons (comprised of two up quarks and one down quark) and neutrons (made up of two down quarks and one up…
Baryonic MatterOrdinary matter, which is made up largely of baryons.
basal1. Located at the base of a plant or a plant organ. 2. A fundamental formulation of a tissue culture medium containing nutrients but no growth promoting…
Basal MetabolismThe amount of heat given off by a person at rest in a comfortable environment; approximately 50 Btu per hour (Btu/h).
BasaltVolcanic rock (or lava), characteristically dark in color and containing 45 to 54% silica and generally rich in iron and magnesium (mafic composition).
baseOne of the components of nucleosides, nucleotides and nucleic acids . Four different bases are found in naturally occurring DNA - the purines A (adenine )…
base analogueA non-natural purine or pyrimidine base that differs slightly in structure from the normal bases, but can be incorporated into nucleic acids .
Base campA site occupied by several families or more on either a year round or a seasonal basis.
Base courseA layer of specified or selected material of planned thickness constructed on the subgrade or subbase for the purpose of serving one or more functions…
BASE DATAThose digital fields of reflectivity, mean radial velocity, and spectrum width data in spherical coordinates provided at the finest resolution available…
Base exchangeThe physicochemical process whereby one species of ions adsorbed on soil particles is replaced by another species.
Base FloodThe flood having a 1% chance of being equaled or exceeded in any given year.
Base flood plainThe flood plain innundated by the 100-year flood.
Base flowGround water inflow to the river. Portion of stream discharge that is derived from natural storage.
base paircombination of 2 nucleotides (A and T or G and C) held together by weak hydrogen bonds; the DNA double helix is formed when a base pair of nucleotides in…
Base pair (bp)A pair of complementary nitrogenous bases in a DNA molecule--adenine-thymine and guanine-cytosine. Also, the unit of measurement for DNA sequences.
Base PowerPower generated by a power generator that operates at a very high capacity factor.
BASE PRODUCTSThose products that present some representation of the base data. This representation may not necessarily be either in full resolution or depict the full…
Base ReflectivityOne of the three fundamental quantities (along with base [radial] velocity and spectrum width) that a Doppler radar measures.
Base safety condition (BSC)The level of loading above which a dam failure does not contribute an incremental loss of life.
Base sequenceThe order of nucleotide bases in a DNA molecule; determines structure of proteins encoded by that DNA.
Base StationA computer which accepts radio signals from ALERT gaging sites, decodes the data, places the data in a database, and makes the data available to other…
base substitutionReplacement of one base by another in a DNA molecule. See: transition; transversion.
Base width or thicknessThe maximum thickness or width of a dam measured horizontally between upstream and downstream faces and normal to the axis or centerline crest of the dam…
Baseboard RadiatorA type of radiant heating system where the radiator is located along an exterior wall where the wall meets the floor.
BaseflowStreamflow which results from precipitation that infiltrates into the soil and eventually moves through the soil to the stream channel.
baselineAn initial measurement that is taken at an early time point to represent a beginning condition, and is used for comparison over time to look for changes.
Baseline Change Request (BCR)A web-based tool that is used to discuss, review, and approve an "engineered product" or other changes to infrastructure components as it is turned over…
Baseline EmissionsThe emissions that would occur without policy intervention (in a business-as-usual scenario).
Baseline profileUsed for a survey of the environmental conditions and organisms existing in a region prior to unnatural disturbances.
BaseloadThe minimum level of electric power demand of a utility, region, or utility customer delivered or required over a given period of time at a steady rate…
Baseload CapacityThe power output of a power plant that can be continuously produced.
Baseload DemandThe minimum demand experienced by a power plant.
Baseload plantPowerplant normally operated to carry baseload; consequently, it operates essentially at a constant load.
Baseload Power PlantA power plant that is normally operated to generate a base load, and that usually operates at a constant load; examples include coal fired and nuclear…
Baseload UnitAn electric power plant, or generating unit within a power plant, that is normally operated continuously to meet the base load of a utility.
BaseloadingRunning water through a powerplant at a roughly steady rate, thereby producing power at a steady rate.
BasementAny area of the building, including any sunken room or sunken portion of a room, having its floor below ground level (subgrade) on all sides.
Basement complexThe suite of mostly crystalline igneous and/or metamorphic rocks that generally underlies the sedimentary rock sequence.
Basement rockThe oldest rocks in a given area; a complex of metamorphic and igneous rocks that underlies the sedimentary deposits.
Basic solutionWater solution with more hydroxide ions (OH-) than hydrogen ions (H+); water solutions with pH greater than 7. See acid solution, alkalinity.
Basin: (1) A depression in the Earth's surface that collects sediment. (2) The area of land that drains to a particular river.
Basin BoundaryThe topographic dividing line around the perimeter of a basin, beyond which overland flow (i.e.; runoff) drains away into another basin.
Basin LagThe time it takes from the centroid of rainfall for the hydrograph to peak.
Basin RechargeRainfall that adds to the residual moisture of the basin in order to help recharge the water deficit. i.
Basin runoff modelAny one of the computer programs that mathematically models basin characteristics to forecast reservoir inflow from rainfall and/or streamflow data.
Basin StatesArizona, California, Colorado, New Mexico, Utah, Wyoming.
Batch HeaterThis simple passive solar hot water system consists of one or more storage tanks placed in an insulated box that has a glazed side facing the sun.
Batch ProcessA process for carrying out a reaction in which the reactants are fed in discrete and successive charges.
BathymetryThe science of measuring depths of the oceans, lakes, seas, etc.
Batt/BlanketA flexible roll or strip of insulating material in widths suited to standard spacings of building structural members (studs and joists).
BatterInclination from the vertical. A pile driven at an angle to widen the area of support and to resist thrust.
BatteryA beating or wrongful physical violence. The threat to use force is an "assault;" the actual use of force is a battery, which usually includes an assault.
Battery capacityThe maximum total electrical charge, expressed in ampere-hours, which a battery can deliver to a load under a specific set of conditions.
Battery Energy StorageEnergy storage using electrochemical batteries. The three main applications for battery energy storage systems include spinning reserve at generating…
BayA regularly repeating division of a façade, marked by fenestration.
Bay-DeltaSacramento/San Joaquin River Delta and San Francisco Bay.