A nephoscope in which the motion of the cloud is observed by its reflection in a mirror.

Same as aneroid barometer. Holostelic means wholly made of solids, while aneroid means devoid of liquid.

The size of the area comprising a watershed or river basin. Also called catchment area.

The total area drained by a river and its tributaries. Same as watershed.

Movernent of water through the soil surface into the soil, or the quantity of water entering the soil. Infiltration is equal to the total precipitation less the losses due to interception by vegetation. retention in depressions on the land surface, evapor ...

A wind (or component thereof) directed down the slope of an incline and caused by greater air density near the slope than at the same levels some distance horizontally from the slope. Also called drainage wind and sometimes called katabatic wind.

An instrument which measures the instantaneous rate at which rain is falling on a given surface. Also called a rate-of-rainfall gauge.

The portion of the precipitation on the land which ultimately reaches the streams. especially the water from rain or melted snow that flows over the surface.

A standard unit of atmospheric pressure, defined as the pressure exerted by a 760 mm column of mercury at standard gravity (980.665 cm/sec2 ) at O

A system of physical units based upon the use of the meter, the metric ton (106 grams), and the second as elementary quantities of length, mass, and time, respectively.

An aviation weather forecast for a specific flight.

An instrument used for measuring the specific gravity of a liquid.

See hook gauge.

An instrument which measures the rate of evapotranspiration. It consists of a vegetation soil tank so designed that all water added to the tank and all water left after evapotranspiration can be measured.

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

An instrument which measures the transmissivity of the atmosphere between two points for the determination of visual range.

Same as fogbow.

A momentary decrease in the speed of the wind.

An instrument used to measure the amount of dew formed on a given surface.

A transducer which converts electromagnetic radiation in the infrared, visible, and ultraviolet regions into electrical quantities such as voltage, current, or resistance. Also called photo cell.