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If the instrument stands on level ground, so that the observer's eye is always at the same height, and if the interval between two successive spikes is equal to one-tenth of their altitude above the eye-level of the observer, one only needs to multiply the time required for the cloud to pass over one interval by 10 to determine the time the ...
A ceilometer is a device that uses a laser or other light source to determine the height of a cloud ceiling or cloud base. [1] Ceilometers can also be used to measure the aerosol concentration within the atmosphere. [2] A ceilometer that uses laser light is a type of atmospheric lidar (light detection and ranging) instrument. [3] [4]
The observer looks through the eyepiece and sets the sight onto the spot projected on the cloud and reads the height from the attached scale. When the cloud is thin the beam of light may penetrate into the cloud. The observer should read the scale where the light first enters the cloud and not at the top.
Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide. [6] They can be taken manually, by a weather observer, by computer through the use of automated weather stations, or in a hybrid scheme using weather observers to augment the otherwise ...
Lidar systems can measure atmospheric temperature from the ground up to approximately 120 km using a variety of techniques, each adapted for a specific altitude range . [33] State-of-the-art lidar systems can combine several of these techniques in one system .
This will give the altitude of the cloud base in feet above ground level. Put in a simpler way, 400 feet for every 1°C dew point spread. For metric divide the spread in °C by 8 and multiply by 1000 and get the cloud base in meters. Add the results from step (2) to the field elevation to obtain the altitude of the cloud base above mean sea level.
ASOS sensors, located at Salinas, California. Surface weather observations have traditionally been taken at airports due to safety concerns during takeoffs and landings. The ICAO defines the International Standard Atmosphere (also known as ICAO Standard Atmosphere), which is the model of the standard variation of pressure, temperature, density, and viscosity with elevation/altitude in the ...
An automatic weather station (AWS) is an automated version of the traditional weather station, either to save human labor or to enable measurements from remote areas. [1] An AWS will typically consist of a weather-proof enclosure containing the data logger , rechargeable battery , telemetry (optional) and the meteorological sensors with an ...