See calorie.

Same as instrument shelter.

Rate of wind movement in distance per unit time.

A large plastic constant-level balloon for duration flying (in excess of 24 hours) at altitudes above 40,000 feet, used for the determination of wind fields and the measurement of upper atmospheric parameters.

In meteorology, an area of low pressure; a low or trough.

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

An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium i ...

Electromagnetic radiation lying within the wavelength interval to which the human eye is sensitive, the spectral interval from approximately 0.4 to 0.7 microns (4000 to 7000 angstroms). Bounded on the short-wavelength end by ultraviolet radiation and on t ...

The actual lifting force of an inflated balloon, usually expressed in grams.

As used by the U.S. Army Corps of Engineers, the departure (in

Tables prepared from the psychrometric formula and used to obtain vapor pressure, relative humidity, and dew point from values of wet-bulb and dry-bulb temperatures.

A method of winds aloft observation essentially the same as a pilot balloon observation except the height data is derived from the radiosonde observation rather than from assumed ascension rates.

A sudden brief increase in the speed of the wind, followed by a lull or slackening. Compare to peak gust.

The greatest distance at which it is just possible to see and recognize with the unaided eye (1) in the daytime, a prominent dark object against the sky at the horizon, and (2) at night, a known, preferably unfocused, moderately intense light source.

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...

The algebraic difference between the upper and lower limits of the measuring range of an instrument, i.e. a thermometer with a range of -35 to 50

Same as water year.

A unit that represents one degree of deviation from a reference point in the mean daily outdoor temperature (usually 65

A cup anemometer with its shaft mechanically coupled to a magneto.

In the direction from which the wind is blowing.