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Glossary /­ FAQs /­ LexiconPrecipitation measuring technology

Gunn-Kinzer Diagram

The Gunn-Kinzer diagram illustrates the relationship between fall velocity, particle size and precipitation types such as rain, drizzle, sleet, snow, hail and mixed precipitation. The method is based on the functionality of the laser precipitation monitor for determining the types of precipitation.

Dew Point

Indicates the temperature, where the saturation limit is reached – under cooling down of the air – and where dewing starts.

Drizzle

Water drops with a diameter of < 0.5 mm, falling down from the atmosphere.

Droplet

A nozzle where the liquid precipitation is passed through, and dripped off in a defined drop size. This procedure achieves a high resolution for the precipitation measurement (e.g. 0.005 mm)

Evaporation

The loss of a certain water quantity, caused by a change of its aggregate state into gaseousness, under temperature influence.

Evaporation Calculation

Mathematical calculation of the evaporation with different parameters:
acc. to HaudeDayʻs value of evaporation from temperature and rel. humidity
acc. to WendlingHourly value of evaporation from temperature, rel. humidity, wind speed and radiation

acc. to Penman-MonteithDay's value of the reference evaporation from temperature, rel. humidity, wind speed and radiation

acc. to RichterDay's value of evaporation above water from wind speed, water surface temperature, rel. air humidity and air temperature

Guidelines

VDI 3786, Part 7: Meteorological measurements, precipitation
DIN 4049, Part 101: Hydrology, terms for precipitation and snow

Hail

Balls of ice with a diameter of approx. > 5 mm, falling down from the atmosphere.

Precipitation

Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the surface.

Precipitation, solid-liquid

Precipitation events in the transition zone between the solid and liquid phases, such as supercooled precipitation, sleet, freezing rain and black ice. To analyze solid-liquid precipitation, we recommend the patented Thies CLIMA technology THERMACERN(R)

Precipitation Intensity

The fallen precipitation quantity within a certain time period (e.g. mm/­min)

Precipitation Meter

Generally for a precipitation collecting instrument, the collected quantity of which is measured by means of a measuring receptacle.

Precipitation Quantity

The totality of the fallen liquid or solid precipitation. Indicated in mm, i.e. 1mm of precipitation = 1 litre per square meter.

Precipitation Recorder

Generally for a precipitation measuring instrument with mechanical ­recording of the collected precipitation quantity.

Precipitation Transmitter

Generally for a precipitation measuring instrument with electrical output. Here, an impulse is delivered for a defined precipitation quantity as output value.

Rain

Water drops with a diameter of > 0.5 mm, falling down from the atmosphere

Snow

Down-falling snow crystals, single or sticking together.

Snow Cross

Inset for precipitation meters. Avoids losses of snow in the precipitation funnel due to wind vorticities.

Tipping Bucket

The collected liquid precipitation is led into a tipping bucket which tips over at a certain weight. The tipping over corresponds to a defined precipitation quantity (e.g. ≥ 0.1 mm)