A mercury barometer which measures atmospheric pressure by weighing the mercury in the column or cistern.

Temperature of equilibrium between the liquid and vapor phases of a substance at a given pressure.

A magnetometer of the electromagnetic type which is used to measure the horizontal intensity of the earth's magnetic field.

The measurement and computation of wind speeds and directions at various levels above the surface of the earth. Methods include pilot balloon observations, rabals, rawin or rawinsonde observations, radar tracking, or acoustic sounding.

A systematic observational error due to the characteristics of the observer. The uncertainty in a reading made by an observer may be acertained by a statistical analysis of his or her readings.

A temperature telemeter.

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

Thermometer for measuring the temperature in the soil at different depths.

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

A cover which fits over a large inflated balloon to facilitate handling in high or gusty winds.

A fixed-length group of bits representing the large data element handled as a unit by a computer. Word length is determined by the capacity of the CPU registers.

Air in motion relative to the surface of the earth. Almost exclusively used to denote the horizontal component.

In general, any self-recording instrument carried aloft by any means to obtain meteorological data.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

modulated radiosonde-A radiosonde which transmits the indications of the meteorological sensing elements in the form of pulses spaced in time. The meteorological data are evaluated from the intervals between the pulses. Also called timeinterval radiosonde ...

An instrument for taking photographs of an image of the sun in monochromatic light.

That portion of the atmosphere which is above the lower troposphere. Generally applied to levels above 850 mb.

Eluding precise prediction, completely irregular.

A system of physical units based on the use of the centimeter, gram. and the second as elementary quantities of length. mass. and time.