The temperature at which an object gives out as much radiation as it receives from its surroundings.

February 2nd. In American folklore, a day that is popularly supposed to provide the key to the weather for the remainder of the winter. Specifically, if the ground-hog upon emerging from its hole casts a shadow, it will return underground, thereby forebod ...

An instrument which automatically records the voltage applied to it, as a function of time.

An instrument which automatically determines the size distribution of raindrops.

A device that combines several separate communications signals into one and outputs them on a single line.

The difference between the air temperature and the dew-point. Also called dew-point deficit, dew-point depression.

Based upon damage patterns, classifies twisters into six categories of wind speed (F0 thru F5), ranging from 40 to 318 mph estimated wind speed.

A rainbow seen in the spray of the ocean. It is optically the same phenomenon as the ordinary rainbow.

The temperature at which all three phases of a substance can exist in equilibrium. This temperature occurs at only one pressure. The triple-point of water is 273.16 K and is the basis of the Kelvin scale.

A small pointer extending downward from the top of the cistern of a Fortin barometer. The level of the mercury in the cistern is adjusted so that it just comes in contact with the end of the pointer, thus setting the zero of the barometric scale.

Operation mode of a communication circuit in which each end can simultaneously transmit and receive.

The component of the radiosonde which includes the modulating blocking oscillator and the radiofrequency carrier oscillator.

A wind scale adapted by the U.S. Forest Service for use in the forested areas of the northern Rocky Mountains (NRM). It is an adaptation of the Beaufort wind scale. The difference between these two scales lies in the specification of the visual effects of ...

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

A calorimetric radiation instrument of historic interest used for the measurement of outgoing heat radiation from the earth during an interval of time. The time integration is performed by allowing the radiation to fall on an uninsulated vessel containing ...

A box-like structure designed to protect certain meteorological instruments from exposure to direct sunlight, precipitation, and condensation, while at the same time providing adequate ventilation. Instrument shelters are painted white, have louvered side ...

The smallest change in the environment that causes detectable change in the indication of an instrument. Compare to sensitivity.

The sum of solar and terrestrial radiation.

Frequency Shift Keying. A form of frequency modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

The maximum rate at which precipitation can pass through the surface into the soil, for a given soil in a given condition.