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Measuring weather
Surface observations - radiation & clouds
Radiation features and various cloud properties are often observed by automated surface stations. Measured variables include:
Sky Condition is a general term for describing the amount of cloud and
how high from the ground they are overhead. For these measurements, laser beam
ceilometers are used to measure the altitude of clouds overhead by recording the
time it takes for a laser beam to hit the cloud and return to the ground. This
is really a remote sensing measurement that is made by the ASOS. Low cloud
measurements are recorded at intervals of 100 feet, while higher cloud
measurements are rounded to the nearest 500 or 1,000 feet. Clouds above 12,000
feet are not reported. By analyzing measurements recorded over 30 minute
intervals, computer algorithms estimate the percentage of the sky that is
covered by cloud. The ASOS reports clear, few, scattered, broken, or overcast
sky conditions along with cloud height information.
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in situ, surface observations, radiation & clouds
Links and resources
Surface observations - radiation & clouds
Radiation features and various cloud properties are often observed by automated surface stations. Measured variables include:
- sky condition - are there clouds?
- visibility - how far can we see?
- present weather - is it raining? windy?
- radiation intensities
Sky Condition is a general term for describing the amount of cloud and
how high from the ground they are overhead. For these measurements, laser beam
ceilometers are used to measure the altitude of clouds overhead by recording the
time it takes for a laser beam to hit the cloud and return to the ground. This
is really a remote sensing measurement that is made by the ASOS. Low cloud
measurements are recorded at intervals of 100 feet, while higher cloud
measurements are rounded to the nearest 500 or 1,000 feet. Clouds above 12,000
feet are not reported. By analyzing measurements recorded over 30 minute
intervals, computer algorithms estimate the percentage of the sky that is
covered by cloud. The ASOS reports clear, few, scattered, broken, or overcast
sky conditions along with cloud height information.
Next page
->
in situ, surface observations, radiation & cloudsLinks and resources
