Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.

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.

Same as atmometer.

The transmission of data collected at a remote location over communications channels to a central station.

A type of electrical thermometer in which the thermal element is a substance whose electrical resistance varies with the temperature. Such thermometers can be made with very short time constants and are capable of highly accurate measurements.

The length of fluid flow (gas or liquid) past a sensor required for the sensor to respond to 63.2% of a step change in speed. Expressed in feet or meters. For anemometers, this value is calculated from time constant times wind tunnel speed.

The array of indicating marks and figure in relation to which the position of an index is observed, i.e. a scale plate on a recorder.

A wind blowing in a direction opposite to the heading of a moving object, thus opposing the object's intended progress; the opposite of a tailwind.

Precipitation composed of white or translucent ice crystals, chiefly in complex branched hexagonal forms.

A rotation anemometer in which the axis of rotation is horizontal. The instrument has either flat vanes (as in the air meter) or helicoidal vanes (as in the propeller anemometer). The relation between wind speed and angular rotation is almost linear.

A balloon-borne instrument for the simultaneous measurement and transmission of meteorological data. It includes transducers for the measurement of pressure, temperature, and humidity; a modulator for the conversion of the output of the transducers to a q ...

Of or pertaining to the air, atmosphere, or aviation. Also, same as antenna.

The ratio of the actual amount of water evaporated into the atmosphere to the evaporative power. Also called relative evaporation.

A measure of the amount of "spin" (or rotation) in the atmosphere.

The temperature at which the liquid and solid forms of a substance may exist in equilibrium at a given pressure (usually one standard atmosphere). The true freezing point of water is known as the ice point.

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

Same as evaporative power.

Instrument which measures and records the amount of evaporation over time.

Same as water year.

Abbreviation for precipitation-evaporation ratio.