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.

A standard unit of atmospheric pressure, defined as the pressure exerted by a 760 mm column of mercury at standard gravity (980.665 cm/sec2 ) at O

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

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 ...

In a system of moist air, the dimensionless ratio of the mass of water vapor to the mass of dry air. For many purposes, the mixing ratio may be approximated by the specific humidity.

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.

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

Same as atmometer.

An early and once universal name for the mercury barometer.

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.

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

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

Liquid water at temperatures colder than freezing.

Same as ombrometer.

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 line drawn through geographical points having the same pluvial index.

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.

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

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