An accumulation of granular ice tufts on the windward sides of exposed objects that is formed from supercooled fog or cloud and built out directly against the wind.

Read Only Memory. A memory that cannot be altered in normal use of a computer, Usually used to store information permanently, such as firmware programs.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.

The length of air flow past a wind vane required for the vane to respond to 50 percent of a step change in wind direction. Expressed in feet or meters and calculated from delay time times wind tunnel speed.

Rate of flow of water past a point in a stream, expressed as volume per unit time, i.e. cubic feet per second.

Companion to the wet-bulb thermometer in a psychrometer. Used to measure ambient air temperature.

An early and once universal name for the mercury barometer.

Electromagnetic radiation lying in the wavelength interval between 0.8 micron and I millimeter. At the lower limit of this interval, the infrared radiation spectrum is bounded by visible radiation, while on its upper limit it is bounded by microwave radia ...

Same as ombrometer.

A line drawn through geographical points having the same pluvial index.

A measure of the degree to which the weather or climate of a region is favorable to the process of evaporation. Usually considered to be the rate of evaporation. under existing atmospheric conditions, from a surface of water which is chemically pure and h ...

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

Same as atmometer.

Liquid water at temperatures colder than freezing.

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

A hygrometer which determines the amount of precipitable moisture in a given region of the atmosphere by measuring attenuation of radiant energy caused by the absorption bands of water vapor.

Downward scattered and reflected solar radiation, coming from the whole hemisphere with the exception of the solid angle of the sun's disc on a surface perpendicular to the axis of this cone.

A type of atmometer. It is a pan used in the measurement of the evaporation of water into the atmosphere. The NWS Class A pan is a cylindrical container 48 inches in diameter and 10 inches deep.

In general, solar radiation received at the earth's surface. Contracted from incoming solar radiation.

Rain gauge which registers precipitation that is too light to be registered by ordinary recording of the depth of water from precipitation. Same as ombrometer.