A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | all


a bright white glare on the underside of clouds, produced by the reflection of light from a snow-covered surface; snowblink is lighter than ice blink, and much lighter than land sky or water sky.


very intense showers of snow, often of short duration, that greatly restrict visibility and produce periods of rapid snow accumulation.


an accumulation or bank of snow formed when wind blows snow against an obstruction; often considerably thicker than the surrounding snowcover.

snowdrift glacier

a semipermanent mass of firn formed by drifted snow behind obstructions or in the ground; also called a catchment glacier or a drift glacier.


the depth of new snow that has accumulated since the previous day or since the previous observation.


a cluster of ice crystals that falls from a cloud.


melting of the snowcover, and also the period during which melting of the snow cover occurs at the end of the winter.


the total snow and ice on the ground, including both new snow and the previous snow and ice which have not melted.


strong wind with snow.

soil wedge

a wedge-shaped body of soil that is different in structure and texture from the surrounding soil.

solar radiation

the total electromagnetic radiation emitted by the sun.


slow downslope flow of saturated unfrozen earth materials.

solifluction apron

a fan-like deposit at the base of a slope, produced by solifluction.

solifluction features

geomorphological features of varying scale produced by the process of solifluction.

solifluction lobe

an isolated, tongue-shaped solifluction feature, up to 25 meters (27 yards) wide and 150 meters (164 yards) or more long; formed by more rapid solifluction on certain sections of a slope showing variations in gradient.

solifluction sheet

a broad deposit of nonsorted, water-saturated, locally derived materials that is moving or has moved downslope.

solifluction terrace

a low step, or bench, with a straight or lobate front, the latter reflecting local differences in the rate of solifluction movement.


the point in time when the vertical rays of the sun are striking either the Tropic of Cancer (23 degrees, 30 minutes N, the summer solstice in the northern hemisphere) or the Tropic of Capricorn (23 degrees, 30 minutes S, the winter solstice in the northern hemisphere); represents the longest or shortest day of the year; in the northern hemisphere, the summer solstice falls on or about 21 June, and the winter solstice on or about 22 December.

sorted circle

a patterned ground form that is equidimensional in several directions, with a dominantly circular outline, and a sorted appearance commonly due to a border of stones surrounding a central area of finer material.

sorted net

a type of patterned ground with cells that are equidimensional in several directions, neither dominantly circular nor polygonal, with a sorted appearance commonly due to borders of stones surrounding central areas of finer material.

sorted polygon

a patterned ground form that is equidimensional in several directions, with a dominantly polygonal outline, and a sorted appearance commonly due to a border of stones surrounding a central area of finer material.

sorted step

a patterned ground feature with a step-like form and a downslope border of stones embanking an area of relatively fine-grained bare ground upslope.

sorted stripe

patterned ground with a striped and sorted appearance, due to parallel strips of stones and intervening strips of finer material, oriented down the steepest available slope.

south pole

90° S latitude; one of the two points where the Earth's axis of rotation meets the Earth's surface (the other being the north pole, diametrically opposite).

specific heat capacity

the amount of heat required to raise the temperature of a unit mass of a substance by one degree.

specific humidity

the mass of water vapor per unit mass of air, including the water vapor (usually expressed as grams of water vapor per kilogram of air).

splay crevasse

a crevasse pattern that forms where ice slowly spreads out sideways; commonly found near a glacier terminus.

sporadic discontinuous permafrost

(1) (North American usage) permafrost underlying 10 - 50% of the exposed land surface (2) (Russian usage) permafrost underlying 5 - 30% of the exposed land surface.

spring equinox

either of the two points of intersection of the sun's apparent annual path and the plane of the earth's equator; in the northern hemisphere, the spring (vernal) equinox falls on or about 21 March, and the autumnal equinox on or about 22 September.

stable air mass

air mass having static stability in its lower layers; it is free from convection, has a low degree of turbulence and may have stratiform clouds or fog, or no clouds.


thick ridges that become grounded during the winter and become part of the fast ice zone; while the rest of the fast ice melts during the summer, a stamukhi remains throughout the summer attached to the ocean bottom.

standard deviation

Statistical measurement of the variation in a distribution: In science, standard deviation serves as measure of the spread of the data, or how likely a data point will fall close to the mean.

static cryosol

a mineral soil showing little or no evidence of cryoturbation, with permafrost within 1 meter (3.3 feet) below the surface.

station pressure

atmospheric pressure observed at a station.

steam fog

evaporation fog formed when water vapor is added to air which is much colder than the vapor's source; most commonly, when very cold air drifts across relatively warm water; also called sea smoke.

steering flow

in meteorology, a basic fluid flow which exerts a strong influence upon the direction of movement of disturbances embedded in it; in the atmosphere, it is usually an air flow in the middle or upper troposphere which govern directions of the disturbances at low levels.