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 Hydrology
variables
The TEMS directory
contains ten core variables related to terrestrial fresh water, these
are:
Surface water
discharge
The volume of water flowing through a river channel cross-section per
unit of time.
variable
sheet
Surface water
storage fluxes
The change in volume and extension of inland water bodies.
variable
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Groundwater
storage fluxes
The groundwater topographic flow that changes over time in the volume
of groundwater that is held in a certain aquifer.
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Precipitation
All deposits on the earth of hail, mist, rain, sleet, snow, dew, fog,
frost, and dust.
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Evapotranspiration
The loss of water to the atmosphere from a given area during a specified
time by evaporation from the soil surface and by transpiration from plants.
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Relative
(air) humidity
It is the ratio, in percent, of the actual amount of water vapour in a
body of air in relation to the maximum amount that the body can hold at
a given temperature. Relative humidity varies with temperature and atmospheric
pressure for a given amount of water vapour. There is no more evaporation
at 100 percent relative humidity.
variable
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Soil moisture
The water content of a defined soil sample.
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Snow water
equivalent
The water content obtained from melting a defined sample of snow.
variable
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Biogeochemical
transport from land to ocean
The amount of carbon (C), nitrogen (N), phosphorus (P), sulphur (S) and
other elements that are transported from land to ocean as dissolved or
suspended particles in streams and rivers.
variable
sheet
Sediment Load
at large river mouths
Freshwater sediment load is the sum of the framework bedload, the matrix
bedload and the suspended solids of an aquatic system. Framework bedload
refers to the larger particles that are moved only during large flow events.
The matrix bedload refers to that part of the bed material that is small
enough to be frequently entrained by low to moderate flows but is large
enough to settle out of the water column in lower velocities. The suspended
load is held in the water column as suspended material for extended periods
of time.
variable
sheet
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