Cryosphere glossary
sail
the part of a ridge above sea level; like a sail on a sailboat, it catches wind and moves the ice.
saline permafrost
permafrost in which part or all of the total water content is unfrozen because of freezing-point depression due to a high dissolved-solids content of the pore water.
salinity
(1) a general property of aqueous solutions caused by the alkali, alkaline earth, and metal salts of strong acids (Cl, SO4 and NO3) that are not hydrolyzed (2) in soil science, the ratio of the weight of salt in a soil sample to the total weight of the sample.
sand wedge
a wedge-shaped body of sand produced by filling of a thermal contraction crack with sand either blown in from above or washed down the walls of the crack.
sand-wedge polygon
a polygon outlined by sand wedges underlying its boundaries.
sastrugi
wind-driven snow shapes that resemble sand dunes; may form on top of sea ice or land-based snow cover; can vary in size and complexity but often forms parallel to prevailing wind direction.
Image
Sastrugi at South Pole Station, Antarctica.
Fred Walton, NOAA Corps Collection
saturation
the condition in which the partial pressure of any fluid constituent (water in the atmospheric air) is equal to its maximum possible partial pressure under the existing environmental conditions, such that any increase in the amount of that constituent will initiate within it a change to a more condensed state; evaporation ceases under such conditions.
saturation vapor pressure (water)
the maximum amount of water vapor necessary to keep moist air in equilibrium with a surface of pure water; this is the maximum water vapor the air can hold for any given combination of temperature and pressure.
scale
(1) a series of marks at regular intervals for the purpose of measuring (scale of an instrument, for example, a thermometer) (2) system of units for measuring ( 3) proportion between the size of something and the map, diagram, etc. which represents it (4) order of magnitude of a phenomenon or of a meteorological parameter.
sea ice
any form of ice found at sea which has originated from the freezing of sea water.
sea ice development stage
A phrase used to classify sea ice for operational purposes using the age of the ice as a proxy for its thickness. Specific terms such as new ice, nilas, young ice, and multiyear ice are used for each stage of sea ice development.
sea ice extent
see ice extent.
sea ice maximum extent
the day of the year when the sea ice covers the largest area of the Arctic or Antarctic.
sea ice minimum extent
the day of the year when the sea ice covers the smallest area of the Arctic or Antarctic
sea smoke
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 steam fog.
sea surface temperature
temperature of the water film at the sea surface.
sea-level pressure
the atmospheric pressure at mean sea level, either directly measured or, most commonly, empirically determined from the observed station pressure.
seasonal freezing index
the cumulative number of degree-days below 0 degrees Celsius, calculated as the arithmetic sum of all the negative and positive mean daily air temperatures (degrees Celsius) for a specific station during the time period between the highest point in the fall and the lowest point the next spring on the cumulative degree-day time curve.
seasonal frost
the occurrence of ground temperatures below 0 degrees Celsius for only part of the year; see also active layer.
seasonal ice zone
an area of ocean that extends from the permanent ice zone to the boundary where winter sea ice extent is at a maximum; here, sea ice is present only part of the year; this zone primarily consists of first-year ice.