Cryosphere glossary
earth hummock
a hummock having a core of silty and clayey mineral soil which may show evidence of cryoturbation.
earth radiation
the total infrared radiation emitted from the earth's surface; to be carefully distinguished from effective terrestrial radiation, atmospheric radiation, and insolation.
edge wasting
process by which warm water erodes iceberg above the waterline
effective terrestrial radiation
the difference between the outgoing infrared (longwave) terrestrial radiation of the earth's surface and the downward infrared counter-radiation from the atmosphere.
electrical conductivity
the inverse of electrical resistivity.
electrical properties of frozen ground
the dielectric constant (or relative permitivity), electrical conductivity and electrical resistivity are the major electrical properties governing the flow of electric current through frozen ground.
electricity resistivity
the property of a material that determines the electrical current flowing through a centimetre cube of the material when an electrical potential is applied to opposite faces of the cube.
electromagnetic wave
an oscillation of the electric or magnetic field associated with the propagation of energy; characterized by their wavelengths and amplitude; propagate at the speed of light.
emissivity
the amount of electromagnetic energy (primarily at wavelengths longer than 1.0 micrometer) that an object emits; for example, the earth emits longwave radiation primarily in the infrared part of the electromagnetic spectrum, but also in longer microwave wavelengths; the emissivity of an object varies as the fourth power of its absolute temperature.
end moraine
an arch-shaped ridge of moraine found near the end of a glacier.
englacial moraine
dust and/or rock inside a glacier. This debris can become lodged in glacial ice after falling through crevasses.
epigenetic ice
ground ice developed in epigenetic permafrost, or in previously formed syngenetic permafrost.
epigenetic ice wedge
an ice wedge developed in epigenetic permafrost, or in previously formed syngenetic permafrost.
epigenetic permafrost
permafrost that formed through lowering of the permafrost base in previously deposited sediment or other earth material.
equator
the line of latitude 0°, which is equidistant from the poles, and which separates the Northern Hemisphere from the Southern Hemisphere.
equi-temperature metamorphism
snow metamorphism that occurs under relatively consistent temperature conditions.
equilibrium line
boundary between the accumulation area and ablation area where the mass balance is zero.
equilibrium metamorphism
snow metamorphism that occurs when there are large differences in convex and concave portions of a crystal.
equilibrium permafrost
permafrost that is in thermal equilibrium with the existing mean annual surface or sea-bottom temperature and with the geothermal heat flux.
equilibrium zone
zone of a glacier in which the amount of precipitation that falls is equal to the amount that melts the following summer.