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The height of the cloud base can be measured using a ceilometer. This device reflects a beam of light off the cloud base and then calculates its distance using either triangulation or travel time. Alternatively, the cloud base can be estimated from surface measurements of air temperature and humidity by calculating the lifted condensation level.
The cloud height, more commonly known as cloud thickness or depth, is the distance between the cloud base and the cloud top. [1] It is traditionally expressed either in metres or as a pressure difference in hectopascal (hPa, equivalent to millibar ).
The LCL is a good approximation of the height of the cloud base which will be observed on days when air is lifted mechanically from the surface to the cloud base (e.g. due to convergence of airmasses).
It marks where the cloud base begins when air is heated from below to the convective temperature, without mechanical lift. [1] Once the CCL is determined, the surface temperature necessary to raise a mass of air to that height can be found by using the Dry Adiabatic Lapse Rate (DALR) to determine the potential temperature. In the early morning ...
An optical drum ceilometer uses triangulation to determine the height of a spot of light projected onto the base of the cloud. [5] It consists essentially of a rotating projector, a detector, and a recorder. [6] The projector emits an intense beam of light above into the sky at an angle that varies with the rotation.
The laser is pointed upward, and the time required for reflected light to return to the station allows for the calculation of the height of the cloud base. Because of the limited coverage area (the laser can only detect clouds directly overhead), the system computer calculates a time-averaged cloud cover and ceiling , which is reported to ...
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The height at which the cloud forms depends on the amount of moisture in the thermal that forms the cloud. Humid air will generally result in a lower cloud base. In temperate areas, the base of the cumulus clouds is usually below 550 metres (1,800 ft) above ground level, but it can range up to 2,400 metres (7,900 ft) in altitude. In arid and ...