Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

A recording anemometer.

Thermodynamic change of state of a system in which there is transfer of heat across the boundaries of the system. Compare to adiabatic process.

A scale of yellows, greens, and blues for recording the color of sea water, as seen against the white background of a Secchi disk.

A numbering system using a base number of 16 and including the ten decimal digits (0 to 9) along with six alpha digits (A to F). Thus. a digit is available to represent each of the possible values of a 4-bit binary digit.

An anemometer utilizing the principle that the pitch of the aeolian tones generated by air moving past an obstacle is a function of the speed of the air. Largely a curiosity and has been put to no practical application in modem meteorology.

A type of pressure-tube anemometer, named after the inventor.

A liquid-in-metal thermometer in which mercury is enclosed in a steel envelope. The change in internal pressure caused by the temperature variation is measured by a Bourdon tube which is connected to the mercury by a capillary tube. This instrument is hig ...

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.

The unit of speed in the nautical system; one nautical mile per hour. It is equal to 1.1508 statute miles per hour or 0.5144 meters per second.

An instrument which records the duration of sunshine and gives a quantitative measure of the amount of sunshine by the action of the sun's rays upon blueprint paper. A type of sunshine recorder.

A radar which is used to obtain the azimuth elevation, and slant range of an airborne target.

An instrument for collecting liquid water from the atmosphere.

A balloon having a detachable tail which is released when the balloon has undergone a predetermined expansion. It thus serves to measure approximately the density of the atmosphere at the point of release.

A cylinder installed in a body of water or an evaporation pan to hold a sensor, such as a float to measure water level or a hook gage. The stillwell is constructed so that there is free movement of water in and out of it, and it therefore provides a repre ...

A large plastic constant-level balloon for duration flying at very high altitudes.

The probability distribution of random errors, typically a normal distribution with a zero mean.

Instrument used to measure the amount of water evaporated from the soil surface during a given time interval.

A recording pressure-tube anemometer in which the wind scale of the float manometer has been made linear by the use of springs, i.e. Dines anemometer.

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