The state of the weather with respect to its effect upon the kindling and spreading of forest fires.

A special form of the aspiration psychrometer. developed by Assmann, in which the thermometric elements are well shielded from radiation. Psychrometric measurements may be taken with the instrument in the presence of direct solar radiation.

An instrument which measures evaporation by measuring the loss of water from a burette reservoir through a ceramic disc.

The value of the quantity measured, as indicated or otherwise provided by a measuring instrument.

Frozen or partly frozen rain.

A seasonal wind of persistent direction, characterized by a pronounced change in direction between seasons.

A measure, proposed by Angstrom, of the precipitation effectiveness of a region.

An instrument, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

Same as water year.

By international agreement, a period during which greatly increased observation of world-wide geophysical phenomena is undertaken through the co-operative effort of participating nations. July 1957-December 1958 was the first such year. However, precedent ...

The volume of liquid water evaporated per unit area in unit time. usually measured as the depth of liquid water lost per unit time from the whole area.

The inherent imprecision of a given process of measurement, the unpredictable component of repeated independent measurements of the same object under sensibly uniform conditions.

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

Solar radiation of selected wavelengths.

A number of quantity defining a limit that errors will not exceed when a device is used under specified operating conditions. Accuracy rating can be expressed in a number of forms, i.e. in terms of the measured variable (+/- 1 C), percent of span (+/-0.5% ...

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

A description or explanation of the manner in which the height of the ceiling is determined, i.e. aircraft ceiling, balloon ceiling. estimated ceiling, indefinite ceiling, measured ceiling, precipitation ceiling.

A balloon used to carry a radiosonde aloft, considerably larger than pilot balloons or ceiling balloons.

A technique for making winds aloft observations in which two theodolites located at either end of a baseline follow the ascent of a pilot balloon. Synchronous measurements of the elevation and azimuth angles of the balloon. taken at periodic intervals, pe ...