Cloud height detection

A scatter profile is measured as described in Measurement of the attenuated backscatter profile.

Cloud height detection is carried out as described in Cloud height calculation. Up to four cloud heights can be detected.

If clouds are not detected, the SkyVue PRO will give one of these reports:

• No significant backscatter.

• Full obscuration determined but no cloud base detected. This is reported if the criteria for detecting cloud base is not met but the integrated scattering coefficient reaches the limit of vertical visibility below a set height limit. The default value is 2000 m (6560 ft) but can be changed by the user. The height at which this occurs is given as vertical visibility.

• Some obscuration detected but determined to be transparent is reported if scattering is detected but no cloud is detected and the calculated vertical visibility exceeds a set height limit.

If no cloud is detected but significant scattering is detected below 50 m (160 ft), then vertical visibility is set to 0.