The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.

An instrument used for the determination of the electrical conductivity of the atmosphere.

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

A coating of ice, generally clear and smooth. formed by the freezing of supercooled water on a surface.

An ice coating with a consistency intermediate between glaze and rime.

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

A hygrometer using goldbeater's skin as the sensitive element. Variations of the physical dimensions of the skin caused by its hygroscopic character indicate relative humidity. (Note: Goldbeater's skin is the prepared outside membrane of the large intesti ...

An instrument used for measuring geometric angles. See radio direction-finder.

Any horizontal wind velocity tangent to the contour line of a constant pressure surface (or to the isobar of a geopotential surface) at the point in question.

Same as geostrophic wind level.

A c.g.s. (centimeter-gram-second) unit of mass. Originally defined as the mass of 1 cubic centimeter of water at 4

See calorie.

See mote.

Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

The minimum temperature shown by a minimum thermometer exposed in an open situation with its bulb at the level of the tops of the grass blades of short turf.

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

A wind (or component thereof) directed down the slope of an incline and caused by greater air density near the slope than at the same levels some distance horizontally from the slope. Also called drainage wind and sometimes called katabatic wind.

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

A direct-vision nephoscope constructed in the following manner: A grid-work of bars is mounted horizontally on the end of a vertical column and made free to rotate about the vertical axis. The observer rotates the grid and adjusts his or her position unti ...