Flux of carbon dioxide from the surface to the atmosphere CO2 flux 422 Volume of water contained in a lake at a given water level. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Lake volume 12280 Rate of movement of sediments in a stream at a given cross-section. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Sediment discharge 12270 Elevation of the water table or piezometric surface of an aquifer at a certain location and time. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Groundwater level 166 Amount (weight, mass or volume) of sediment that moves on or near the streambed by rolling, sliding, or saltating (bed load) transported through a cross-section of a stream per unit time. [Based on 'bed load discharge' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Bed load discharge 12271 The mass removed from the glacier at a point on its surface expressed over a stated period of time. Surface ablation at a point 12012 Map of land surface heights. Land surface topography 237 Maximum rate at which water can penetrate the soil matrix per unit area under certain conditions. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Infiltration capacity 12262 Ice thickness 725 Power radiated by the fire occurring within an area. Fire radiative power 387 Ice thickness 726 Temperature of the fire occurring within an area. Fire temperature 388 Property of a porous medium or fractured rock which, according to Darcy's law, relates the specific discharge to the hydraulic gradient. [based on 'hydraulic conductivity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Hydraulic conductivity 12256 Rate at which water is transferred through a unit width of an aquifer under a unit hydraulic gradient. [Based on 'transmissivity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Hydraulic transmissivity 12257 52 Velocity of the ice measured at the surface of a glacier. Glacier motion 611 Map of the height of the glacier surface. Glacier topography 612 Processed from land surface imagery by assigning identified cluster(s) within a given area to specific classes of objects - Accuracy expressed as number of classes. Actually [ classes-1 ] is used, so that smaller figure corresponds to better performance, as usual. Land cover 236 Ratio of the distance covered by a body of water, moving in a specified direction, to the time taken to cover that distance. [Based on 'velocity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Stream velocity 12322 The result of all processes adding and removing mass from the glacier at a point on its surface, expressed over a stated period of time Glacier mass balance at a point 12009 Velocity at a given cross-section of a stream, obtained by dividing the discharge by the cross-sectional area of the stream at that section. [Based on 'mean velocity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Stream mean velocity 12323 Observed variable - measurand (terrestrial and hydrological) Volume of water flowing through a stream (or channel) cross-section per unit time. [Based on 'discharge' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Stream discharge 171 Volume of the void spaces through which water or other fluids can travel in rock or sediment, divided by the total volume of the rock or sediment. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Effective porosity 12259 Volume of geological formation capable of storing, transmitting and yielding exploitable quantities of water. [Based on 'aquifer' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Aquifer volume 12255 Total amount of vegetation in a reference area Biomass 423 The Vertical depth of the water that would be obtained if the snow cover melted completely, which equates to the snow-cover mass per unit area. Water equivalent of snow cover 631 Observed variable - measurand (terrestrial and hydrological) Result of the classification of different types of vegetation within a vegetated area - Accuracy expressed as inverse of the number of classes, so that smaller figures correspond to better performance. Vegetation type 427 Fraction of PAR absorbed by vegetation (land or marine) for photosynthesis processes (generally around the 'red' frequencies). Fraction of Absorbed PAR (FAPAR) 563 Fraction of an area flood by water. Wetland extent 243 Volume of groundwater flowing through an aquifer per unit time. [Based on International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Groundwater flow 12265 Volume of water in a reservoir between the minimum and maximum water levels under normal operating conditions. Synonyms: usable storage, active storage, available storage capacity. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Live storage 12278 Volume of a reservoir including dead storage. Synonym: total storage. [Based on 'total storage' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Reservoir storage 12279 The standard depths for soil temperature measurements are 5, 10, 20, 50 and 100 cm below the surface; additional depths may be included. The site for such measurements should be a level plot of bare ground (about 75 cm^2 ) and typical of the surrounding soil for which information is required. Soil temperature 596 The result of all processes adding and removing mass from the glacier at its surface, expressed over a stated period of time and integrated over the entire glacier area Glacier-wide mass balance 12010 The mass added to the glacier at a point on its surface expressed over a stated period of time. Surface accumulation at a point 12011 The area of snow-covered ground, ice, or firn based on the fractional threshold used to define presence of snow. Snow cover extent 628 That part of the total transported sediment which is suspended by turbulence in the flowing water for considerable periods of time without contact with the stream bed, moving with almost the same velocity as the flowing water and generally expressed in mass or volume per unit of time. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Suspended sediment load 12272 Fraction of a land area where fire is occurring. Fire fractional cover 386 Amount of water present beneath the ground surface per unit area. Groundwater (amount per unit area) 165 Surface velocity of a single rock glacier unit. Rock glacier velocity 12283 Flux of downwelling photons of wavelength 400-700 nm. Photosynthetically Active Radiation (PAR) 564 Difference in the stage of water surface over a short stream reach. [Based on 'water surface slope' in Manual on Stream Gauging (WMO-No. 1044), Volume II. 2010.] Water surface slope 12325 Ratio of runoff depth to precipitation depth. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Runoff coefficient 12275 That part of the precipitation which flows on the ground surface (surface runoff) or within the soil (subsurface runoff or interflow) and is generally expressed in mass or volume per unit of time, its equivalent in linear units (as the height of a water layer covering a given area) or as a fraction of precipitation. [Based on International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Runoff 12274 Result of the classification of different types of soil within an area - Accuracy expressed as inverse of the number of classes, so that smaller figures correspond to better performance. Soil type 246 A binary observation of the presence of snow cover at the measurement location. Presence of snow 12007 Vertical depth of the water that would be obtained if the freshly fallen snow melted completely, which equates to the new snow mass per unit area. Water equivalent of snowfall 12008 Fractional content of water in a volume of wet soil. Typically in a layer from the surface down to approximately 3 meters. Soil moisture (in the roots region) 527 Fractional content of water in a volume of wet soil. Surface layer (upper few centimetres). Soil moisture at surface 528 Elevation of the free water surface of a water body flowing in an open or closed conduit. [Based on 'water level'and 'stream' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Stream level 172 Quantity of water evaporated from the soil and plants when the ground is at its natural moisture content. Evaporation 510 Binary product (dry or wet) expressing the presence of liquid water at the surface of the snow cover. Snow surface state 630 Location of coastlines (Lat/Long) Coastlines 232 Ground temperature measured in the permafrost. Permafrost temperature 12014 Thickness of the surface layer of the ground that is subject to annual thawing and freezing in areas underlain by permafrost. Active layer thickness 12015 Ratio of the volume of water which can be drained by gravity from an initially saturated porous medium to the total volume of the porous medium. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Specific yield 12264 Natural or artificial introduction of water into the saturated zone of an aquifer for a unit time. [Based on 'groundwater recharge' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Recharge rate 12254 Percentage of water in soil expressed relative to dry-soil weight or by volume.Synonym: water content of soil. [Based on 'soil moisture content' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Soil moisture 12277 The concentration of all dissolved substances in water, usually expressed in milligrams per litre, which would remain as a solid residue after removal of the water. [Manual on Water Quality Monitoring (WMO-No. 680). 1988] Total dissolved solids 12267 Well discharge 174 Difference between maximum (in NIR) and minimum (around the Red) vegetation reflectance, normalised to the summation. Representative of total biomass, supportive for computing LAI if not directly measured. Normalised Difference Vegetation Index (NDVI) 426 Temperature of the lake surface. Lake Surface Temperature 410 Map of ice sheet height over land. Ice sheet topography 613 The vertical depth of freshly fallen snow that has accumulated during a specific period. Depth of snowfall 627 Area enclosed by the projection of the glacier outline onto the surface of an ellipsoid approximating the surface of the Earth or onto a planar horizontal approximation to that ellipsoid. The glacier area excludes nunataks but includes debris-covered parts of the glacier. The glacier outline separates the glacier from unglacierized terrain and from contiguous glaciers. Glacier area 12013 Flow of water through the soil surface into a porous medium for a unit time. [Based on 'infiltration' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Infiltration rate 12261 Amount of suspended sediment (suspended by turbulence for considerable periods of time without contact with the bed) crossing a stream section per unit time. [Based on 'suspended sediment' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Suspended sediment discharge 12281 Area extent of the surface of a lake. Lake area 167 A velocity that is representative of the average stream velocity; often measured in a profile or across the stream or over the water surface. [Based on 'velocity index method' in Manual on Stream Gauging (WMO-No. 1044), Volume II. 2010] Stream index velocity 12282 Runway conditions 239 Vertical distance from the snow surface to a stated reference level. Snow depth 629 Total quantity of sediment passing through a reach, both in suspension and along the bed, excluding the sediment deposited on the bed within the reach. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Total sediment load 12273 Ratio of discharge of a well to drawdown at equilibrium. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Specific capacity (well) 12263 Soil heat Flux 245 Temperature of the apparent surface of land (bare soil or vegetation). Land surface temperature 389 The component of an unacidified water sample that is retained by a 0.45-nm membrane filter. [Manual on Water Quality Monitoring (WMO-No. 680). 1988] Suspended sediment 12268 Ratio of the volume of the interstices in a given sample of a porous medium to the gross volume of the sample, inclusive of voids. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Porosity 12258 Velocity of a stream at its surface at a given point. [Based on 'surface velocity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Stream surface velocity 12324 Elevation of the free water surface of a water body relative to a reference datum (synonym: stage, gage height). [Based on 'water level' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Water level 12252 Flow of a liquid through an unsaturated porous medium, such as that of water in soil under the effect of gravity for a unit time. [Based on 'percolation' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Percolation rate 12253 (1) Impounding of water in surface or underground reservoirs for future use. (2) Volume of water stored. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Storage 12266 Fraction of a land area where vegetation is present. Fraction of vegetated land 424 LAI (Leaf Area Index, LAI) is the total one-sided area of photosynthetic tissue per unit ground surface area. Leaf Area Index (LAI) 425 Elevation of water in an inland body of surface water of significant extent. [Based on 'water level' and 'lake' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Lake level 168 Breaking action-friction coefficient 231 2024-01-02T17:12:38.555Z Runoff volume from a drainage basin, divided by its area, in a specified time. [International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Depth of runoff 12276 Amount of water held in the soil after gravitational water has drained away expressed as a volume percentage. [Based on 'specific retention' and 'field capacity' in International Glossary of Hydrology (WMO-No. 385). 2012 edition.] Specific retention 12260