A momentary decrease in the speed of the wind.

See captive balloon, ceiling balloon, constant-level balloon, free balloon, hurricane beacon, kytoon, Moby Dick balloon, pilot balloon, radiosonde balloon, rockoon, skyhook balloon, transosonde.

The height of the cloud base above the local terrain.

The amount of precipitation captured by a rain gauge.

Apparatus consisting of (a) standard radiosonde and radiosonde ground equipment to obtain upper-air data on pressure, temperature, and humidity, and (b) a self-tracking radio direction-finder to provide the elevation and azimuth angles of the radiosonde s ...

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.

Same as wave pole.

A surface weather observation, made at periodic times, of sky cover, state of the sky, cloud height, atmospheric pressure reduced to sea level, temperature, dew point, wind speed and direction. amount of precipitation, hydrometeors and lithometeors. and s ...

A vent used with pressure sensors to reduce the effect of wind on the pressure inlet. It is normally mounted remotely and connected to the sensor using airtight tubing.

An up slope wind due to local surface heating. Opposite of katabatic wind.

Same as ombrometer.

The effect upon the measurement of rainfall caused by the presence of the rain gauge.

The direction from which the wind is blowing, measured in points of the compass or in azimuth degrees.

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.

A measure of the relative power, or of the relative values of two flux densities, especially of sound intensities and radar power densities. The decibel is derived from the less frequently used unit, the bel, named in honor of Alexander Graham Bell.

A colorless and odorless gaseous element. The lightest and apparently the most abundant chemical element in the universe. However, it is found only in trace quantities in the observable portion of our atmosphere, only about 0.00005 percent by volume of dr ...

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.

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

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