Weather — page 9 of 38

Weather terms

801. Current Meter Device used to measure the water velocity or current in a river.
802. Curtain Drain A drain constructed at the upper end of the area to be drained, to intercept surface or ground water flowing toward the protected area from higher ground…
803. Cutoff An impervious construction by means of which water is prevented from passing through foundation material.
804. Cutoff Low A closed upper-level low which has become completely displaced (cut off) from basic westerly current, and moves independently of that current.
805. CVR Cover
806. CWA Clean Water Act, California Waterfowl Association.
807. CWFA County Warning and Forecast Area
808. CYC Cyclone- A large-scale circulation of winds around a central region of low atmospheric pressure, counterclockwise in the Northern Hemisphere, clockwise in…
809. CYCLGN Cyclogenesis - The formation or intensification of a cyclone or low-pressure storm system.
810. Cyclic Storm A thunderstorm that undergoes cycles of intensification and weakening (pulses) while maintaining its individuality.
811. Cyclogenesis (Abbrev. CYCLGN) - The formation or intensification of a cyclone or low-pressure storm system.
812. Cyclolysis Cyclolysis Process of weakening or terminating of a cyclonic circulation in the atmosphere; the opposite of cyclogenesis.
813. Cyclone (abbrev. CYC) - A large-scale circulation of winds around a central region of low atmospheric pressure, counterclockwise in the Northern Hemisphere…
814. Cyclone movement Cyclone movement The spatial displacement of a center of low pressure caused by the local redistribution of mass in the atmosphere.
815. Cyclonic Circulation Circulation (or rotation) which is in the same sense as the Earth's rotation, i.e.
816. D Dust
817. D Region In solar-terrestrial terms, a daytime layer of the earth's ionosphere approximately 50 to 90 km in altitude.
818. Daily Climatological Report As the name indicates, this climatological product is issued daily by each National Weather Service office.
819. Daily Flood Peak The maximum mean daily discharge occurring in a stream during a given flood event.
820. DALR Dry Adiabatic Lapse Rate
821. Dam A structure for impeding and controlling the flow of water in a water course, and which increases the water elevation to create the hydraulic head.
822. Dam Failure Catastrophic type of failure characterized by the sudden, rapid, and uncontrolled release of impounded water.
823. DAMBRK In hydrologic terms, the Dam Break Forecasting Model.
824. Dansgaard-Oeschger event one of a series of climate changes during the last glacial period that occurred roughly every few thousand years.
825. DAPM In hydrologic terms, the Data Acquisition Program Manager.
826. Dark Surge on Disk (DSD) In solar-terrestrial terms, dark gaseous ejections visible in H-alpha.
827. Dart Leader A faint, negatively charged channel that travels more or less directly and continuously from cloud to ground.
828. Data Archive Serves as long-term storage for ARM data to keep data easily accessible. It is located at Oak Ridge National Laboratory.
829. Data Management Facility (DMF) (DMF) Manages ARM datastream and provides for the collection, processing, analysis, and delivery of ARM data.
830. Data Management System (DMS) (DMS) Controls the data flow and minimizes data loss. Its primary functions are data collection, storage, and processing.
831. data object description The basic information, definitions, and metadata required to process "raw" measurement data to standard NetCDF files.
832. Data Point In the context of hydrologic observations, a location on a river/stream for which observed data is input to RFC or WFO hydrologic forecast procedures, or…
833. Data Quality Assessment Report (DQAR) (DQAR) An assessment report issued by the Data Quality Office and/or instrument mentors based on a data quality inspection.
834. Data Quality Health and Status (DQ HandS) (DQ HandS) The Data Quality Office website that displays automatically generated data quality results.
835. Data Quality Office (DQO) (DQO) Formed in July 2000 to coordinate ARM's Data Quality Program.
836. Data Quality Problem Report (DQPR) (DQPR) An ARM infrastructure problem report issued to site operators by the Data Quality Office, instrument mentors, and/or site scientists to report a problem…
837. Data Quality Program Run by the ARM Program Data Quality Office to help coordinate the continued evolution and implementation of efforts to assure the quality of the data…
838. Data Quality Report (DQR) (DQR) Used to identify and document problems with ARM systems, physical infrastructure, or instruments.
839. DATACOL The Software System that supports RFC gateway functions.
840. DATANET Hydrologic Data Network Analysis Software
841. datastream Similar files that are in a time-sequenced series.
842. Dawn Same as Civil Dawn; the time of morning at which the sun is 6 degrees below the horizon.
843. Day Length Duration of the period from sunrise to sunset.
844. dBZ Nondimensional "unit" of radar reflectivity which represents a logarithmic power ratio (in decibels, or dB) with respect to radar reflectivity factor, Z.
845. DCP (Data Collection Platform) In hydrologic terms, an electronic device that connects to a river or rainfall gage that records data from the gage and at…
846. DDS A rare disorder that causes kidney failure before age 3, abnormal development of the sexual organs, and, in most cases, Wilms tumor (a type of kidney…
847. Dead Storage The volume in a reservoir below the lowest controllable level.
848. Debris Cloud A rotating "cloud" of dust or debris, near or on the ground, often appearing beneath a condensation funnel and surrounding the base of a tornado.
849. Decadal Occurring over a 10-year period, such as an oscillation whose period is roughly 10 years ("Pacific Decadal Oscillation").
850. Deciduous trees Trees such as oaks and maples that lose their leaves during part of the year. See coniferous trees.
851. Declination The angular position of the sun at solar noon with respect to the plane of the equator.
852. Decomposition The process of breaking down organic material; reduction of the net energy level and change in physical and chemical composition of organic material.
853. Deep Percolation Loss Water that percolates downward through the soil beyond the reach of plant roots.
854. Deep Seepage Infiltration which reaches the water table.
855. Deep well A well whose pumping head is too great to permit use of a suction pump.
856. Deepening A decrease in the central pressure of a surface low pressure system. The storm is intensifying.
857. deepwater an ocean water mass with relatively uniform temperature, salinity, and density, found near the bottom of the ocean.
858. Deforestation Those practices or processes that result in the conversion of forested lands for non-forest uses.
859. Deformation Zone The change in shape of a fluid mass by variations in wind, specifically by stretching and/or shearing.
860. Deformed Ice A general term for ice which has been squeezed together and forced upwards and downwards in places.
861. Degradable See biodegradable.
862. Degradation Process wherein the elevation of streambeds, sandbars, and flood plains is lowered by erosion. The opposite of aggradation.
863. Degree Day A unit for measuring the extent that the outdoor daily average temperature (the mean of the maximum and minimum daily dry-bulb temperatures) falls below…
864. Delta The relationship between an option's price and the price of the underlying stock or futures contract is called its delta.
865. Delta T Change in temperature. 1) A simple representation of the mean lapse rate within a layer of the atmosphere, obtained by calculating the difference between…
866. Dendrites Thin branch-like growth of ice on the water surface.
867. Dendritic Channel pattern of streams with tributaries that branch to form a tree-like pattern.
868. Dense Fog Advisory Issued when fog reduces visibility to 1/8 mile or less over a widespread area.
869. Density The average number of people, families, or housing units on one unit of land. Density is also expressed as dwelling units per acre.
870. Density Current A flow of water maintained by gravity through a large body of water, such as a reservoir or lake, and retaining its unmixed identity because of a…
871. Density of Snow The ratio, expressed as a percentage, of the volume which a given quantity of snow would occupy if it were reduced to water, to the volume of the snow.
872. DEP Departure
873. Depletion Curve That part of the hydrograph extending from the point of termination of the Recession Curve to the subsequent rise or alternation of inflow due to…
874. Deposition An oral statement made before an officer authorized by law to administer oaths.
875. Depression A depression is a severe and prolonged downturn in the economy. Prices fall, reducing purchasing power.
876. Depression Storage The volume of water contained in natural depressions in the land surface, such as puddles.
877. Depth of Runoff The total runoff from a drainage basin, divided by its area. For convenience in comparing runoff with precipitation, the term is usually expressed in…
878. Depth of snow Depth of snow Vertical interval between the top surface of a snow layer and the ground beneath; the layer is assumed to be evenly spread over the ground…
879. Derecho (Pronounced day-RAY-cho), a widespread and usually fast-moving windstorm associated with convection.
880. derived product A new datastream generated by applying an algorithm or model to existing data.
881. Derived Products Processed base data on the Doppler radar.
882. Desertification When soil erosion is so severe that plants and animals can no longer exist.
883. Design Criteria The hypothetical flood used in the sizing of the dam and the associated structures to prevent dam failure by overtopping, especially for the spillway…
884. Detention Basins Detention basins are normally dry, but are designed to detain surface water temporarily during, and immediately after a runoff event.
885. Detention Storage The volume of water, other than depression storage, existing on the land surface as flowing water which has not yet reached the channel.
886. Detritus Loose natural materials, such as rock fragments or organic particles, that result directly from disintegration of rocks or organisms.
887. Deuterium A special form of hydrogen (an isotope called "heavy hydrogen") that has a neutron as well as a proton in its nucleus.
888. Developing Gale/Storm In the high seas and offshore forecasts, a headline used in the warnings section to indicate that gale/storm force winds are not now occurring but are…
889. Dew Moisture in the air that condenses on solid surfaces when the air is saturated with water vapor.
890. Dew point The temperature to which air with a given quantity of water vapor must be cooled to cause condensation of the vapor in the air.
891. Dew Point Depression The difference in degrees between the air temperature and the dew point.
892. Dew Point Front A narrow zone (mesoscale feature) of extremely sharp moisture gradient and little temperature gradient. It separates moist air from dry air.
893. DEWP On a buoy report, the dewpoint temperature taken at the same height as the air temperature measurement.
894. DFUS Diffuse
895. Diabatic A process which occurs with the addition or loss of heat. The opposite of adiabatic.
896. Diablo Wind Similar to Santa Ana winds in southern California. These winds occur below canyons in the East Bay hills (Diablo range) and in extreme cases can exceed 60…
897. Diagnostic Model A computer model used to calculate air pollution concentrations. A diagnostic model produces a wind field over an area by interpolating from actual wind…
898. Diamond Dust A fall of non-branched (snow crystals are branched) ice crystals in the form of needles, columns, or plates.
899. Diatom Single-celled or colonial algae whose cell walls are made of silica.
900. Differential Motion Cloud motion that appears to differ relative to other nearby cloud elements, e.g.