Salt haze-
A haze created by the presence of finely divided particles of sea salt in the air, usually derived from the evaporation of sea spray.
Sand haze-
Reduced visibility in the atmospheric boundary layer caused by suspended particles of soil, mixed into the air during strong winds.
Saturation deficit-
The amount by which the water vapor in the air must be increased to achieve saturation without changing the environmental temperature and pressure.
Saturation mixing ratio-
A thermodynamic function of state; the value of the mixing ratio of saturated air at the given temperature and pressure.
Saturation vapor pressure-
The vapor pressure of a system, at a given temperature, for which the vapor of a substance is in equilibrium with a plane surface of that substances pure liquid or solid phase; that is, the vapor pressure of a system that has attained saturation but not supersaturation.
Scale height-
The height within which some parameter, such as pressure or density, decreases by a factor 1/e in an isothermal atmosphere.
Slantwise convective available potential energy-
(SCAPE), the total amount of potential energy available for conversion into kinetic energy in the slantwise upward displacement of a particular sample of air in an atmosphere that is unstable to slantwise convection.
Scattering-
In a broad sense, the process by which matter is excited to radiate by an external source of electromagnetic radiation, as distinguished from emission of radiation by matter, which occurs even in the absence of such a source.
Scattering coefficient-
A measure of the extinction due to scattering of monochromatic radiation as it traverses a medium containing scattering particles.
Scavenging by precipitation-
Removal of pollutants from the air by either rain or snow. Rainout (or snowout), which is the in cloud capture of particulates as condensation nuclei, is one form of scavenging.
Sea breeze-
A coastal local wind that blows from sea to land, caused by the temperature difference when the sea surface is colder than the adjacent land.
Sea breeze front-
The horizontal discontinuity in temperature and humidity that marks the leading edge of the intrusion of cooler, more moist marine air associated with a sea breeze.
Sea ice-
Specifically, ice formed by the freezing of seawater; as opposed, principally, to land ice.Generally, any ice floating in the sea.
Sea level pressure-
The atmospheric pressure at mean sea level, either directly measured or, most commonly, empirically determined from the observed station pressure.
Sea surface temperature-
The temperature of the ocean surface.
Seclusion-
A special (and rare) case of the process of occlusion, where the point at which the cold front first overtakes the warm front (or quasi stationary front) is at some distance from the apex of the wave cyclone.
Sedimentation-
The process of depositing material by water, wind, or glaciers.
Severe storm-
In general, any destructive storm, but usually applied to severe local storms in particular, that is, intense thunderstorms, hailstorms, and tornadoes.
Shallow convection parameterization-
The representation in a numerical model of the turbulent transports of heat and moisture by nonprecipitating cumulus clouds with cloud tops below 3000 m above the surface.
Shallow water wave-
An ocean wave with its length sufficiently large compared to the water depth (i.e., 25 or more times the depth)
Shelf cloud-
A low level, horizontal, wedge shaped arcus cloud associated with a convective storms gust front.
Short wave-
With regard to atmospheric circulation, a progressive wave in the horizontal pattern of air motion with dimensions of cyclonic scale, as distinguished from a long wave.
Slantwise convection-
A form of convection driven by a combination of gravitational and centrifugal forces.
Slantwise convective available potential energy-
The total amount of potential energy available for conversion into kinetic energy in the slantwise upward displacement of a particular sample of air in an atmosphere that is unstable to slantwise convection.
Smog-
A natural fog contaminated by industrial pollutants, a mixture of smoke and fog.
Snow generating level-
A layer in the middle or upper troposphere in widespread precipitation in which ice crystals form in small convective cells and fall to lower altitudes.
Solar radiation-
The total electromagnetic radiation emitted by the sun.
Sounding-
A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation.
Specific humidity-
In a system of moist air, the (dimensionless) ratio of the mass of water vapor to the total mass of the system.
Spectral radiance-
The radiance per unit wavelength or wavenumber interval.
Splitting convective storm-
The process by which a single convective cell splits into two supercells, one dominated by cyclonic rotation and the other by anticyclonic rotation, their paths then deviating substantially from each other and other nearby convective cells.
Squall-
A strong wind characterized by a sudden onset, a duration of the order of minutes, and then a rather sudden decrease in speed.
Squall line-
A line of active thunderstorms, either continuous or with breaks, including contiguous precipitation areas resulting from the existence of the thunderstorms.
Stability-
The characteristic of a system if sufficiently small disturbances have only small effects, either decreasing in amplitude or oscillating periodically; it is asymptotically stable if the effect of small disturbances vanishes for long time periods.
Stack effect-
An effect due to heat sources within a local exhaust enclosure (stack) producing convective air currents with vertical velocities proportional to the rate of heat transferred to the surrounding air and to the height of rise of the heated air.
Standing wave-
A wave that is stationary with respect to the medium in which it is embedded, for example, two equal gravity waves moving in opposite directions.
Static stability-
The ability of a fluid at rest to become turbulent or laminar due to the effects of buoyancy.
Stationary eddies-
In studies of the general circulation, the eddies are the departures of a field from the zonal mean of that field; the stationary eddies are the time averaged, or time invariant, component of the eddy field.
Swell-
Surface gravity waves on the ocean that are not growing or being sustained any longer by the wind.
