A Comparative Study of Cloud Observation between Instrumental Measurements and Visual Observations

Abstract:

The microphysical observations of clouds have been performed by human observers who record the amount,
height, and type of cloud. However, the observational methods of clouds by human observers have
their limitations due to its difficulties in the punctuality and weakness of assessment.
The Automatic Cloud Observation System(ACOS) has been developed by NIMR to obtain continuous information
of the amount and height of clouds. A set of ACOS is composed of two cameras
and the amounts and heights of clouds are retrieved from the sky images.
Four sets of the ACOS were installed during last 4 years at four locations in South Korea.
They are compared with cloud observation data from visual observations and instrumental measurements
using ceilometers, radiometers, and another camera-type instrument named “Sky View”.
Recent two-year observation data are analyzed, focused on the differences of cloud amounts
and heights between cloud observation methods.