Hydrometeorological Report (HMR)A series of hydrometeorological reports published by the National Weather Service (NWS) addressing meteorological issues related mainly to developing…
Hydrometeorological TechniciansIndividuals whose duties include data collection, quality control, gage network maintenance, as well as the gathering and disseminating of data and…
HydrometeorologistsIn hydrologic terms, individuals who have the combined knowledge in the fields of both meteorology and hydrology which enables them to study and solve…
HydrometeorologyAn interÂdisciÂplinary science involving the study and analysis of the interÂrelationÂships between the atmoÂspheric and land phases of…
HydrometerA device for measuring the specific gravity of fluids.
Hydronic Heating SystemsA type of heating system where water is heated in a boiler and either moves by natural convection or is pumped to heat exchangers or radiators in rooms…
HydrophilicHaving a strong affinity (liking) for water. The opposite of hydrophobic.
HydrophobicHaving a strong aversion (dislike) for water. The opposite of hydrophilic.
hydrophobic interactionAn interaction between a hydrophobic ('water-hating') part of a molecule and an aqueous environment.
hydroponicsThe growing of plants without soil. Plants are fed with an aerated solution of nutrients, and the roots are either supported within an inert matrix, or…
HydropowerThe force of flowing water moving downstream creates energy that can be harnessed and turned into electricity.
HydrosphereThe region that includes all the earth's liquid water, frozen water, floating ice, frozen upper layer of soil, and the small amounts of water vapor in the…
HydrostaticRelating to pressure or equilibrium of fluids. The pressures and forces resulting from the weight of a fluid at rest.
Hydrostatic HeadA measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure.
HydrostratigraphicGrouping of rock and sedimentary units based on the capacity of the rock, sediment, or soil to transmit water.
Hydrothermal fluidsThese fluids can be either water or steam trapped in fractured or porous rocks; they are found from several hundred feet to several miles below the…
HydroxyapatiteA natural mineral structure that contains calcium and phosphate ions that provide the power for the formation of bones and teeth.
HydroÂmeteorologyAn interÂdisciÂplinary science involving the study and analysis of the interÂrelationÂships between the atmoÂspheric and land phases of…
HyetographA graphical representation of rainfall intensity with respect to time.
HygrometerAn instrument which measures the humidity of the air.
hygromycinAn antibiotic used as selective agent in bacterial and transgenic plant cell cultures.
HygroscopicAbsorbing or attracting moisture from the air.
hygroscopic growthThe rate that aerosol particles grow at relative humidity values less than 100 percent.
Hyperconcentrated flowMoving mixture of sediment and water between 40 and 80 percent water by volume.
hyperploidThe situation in which a particular chromosome or chromosome segment is present in more than the normal number. Opposite: hypoploid.
hypersensitive response1. A specific reaction of a plant to attack by a pathogen. The plant cells surrounding the point of infection rapidly die and dry out, so that pathogen…
hypersensitive siteRegions in the DNA that are highly susceptible to digestion with restriction endonucleases.
hypertonicA solution with an osmotic potential greater than that of living cells. Treatment with such solutions leads to the plasmolysis of cells.
hypervariable regionThe parts of both the heavy and light chains of an antibody molecule that enable it to bind to a specific site on an antigen.
hypervariable segmentA region of a protein that varies considerably between strains or individuals.
HypoblastThe inner cell layer, or endoderm, which develops during the formation of the embryonic germ layers.
HypocenterThe point or focus within the earth which is the center of an earthquake and the origin of its elastic waves.
hypocotylThe portion of an embryo or seedling below the cotyledons . A transitional area between stem and root.
HypolimneticPertaining to the lower, colder portion of a lake or reservoir which is separated from the upper, warmer portion (epilimnion) by the thermocline.
HypolimnionThe lower, or bottom, layer of a lake or reservoir with essentially uniform colder temperatures.
hypomorphA mutation that reduces, but does not completely abolish gene expression.
hypoplasticDefective and reduced growth or development (e.g. dwarfing and stunting in plants) resulting from an abnormal condition, for example disease or…
hypoploidThe situation in which a particular chromosome or chromosome segment is present in less than the normal number. Opposite: hyperploid.
Hyporheic zoneGround water habitats created by the movement of river water from the active channel to areas to the side and beneath the active channel.
hypothalamic peptidesPeptides generated in the vertebrate forebrain and concerned with regulating the body's physiological state.
Hypothermiathis situation occurs when the core temperature of one's body falls below normal.
HypothesisA tentative proposal made to explain certain observations or facts that requires further investigation to be verified.
hypotonicOsmotic potential less than that of living cells. Cells placed in a hypotonic solution will absorb water and display swelling and turgidity.
HypsographyElevation measurement system based on a sea level datum.