Issues for observation of clouds from aircraft

(Section 2.5.1)

Cloud observations from an airborne observer can provide different information to that from an observer at the Earth’s surface. An airborne observer can have more complete knowledge of the vertical distribution of the clouds, their amounts and altitudes, their structure and the appearance of their upper parts or surfaces, as well as their constituent particles.

The appearance of the clouds depends on their position relative to the aircraft, so it is necessary to state the conditions under which observations are made. Descriptions of appearance in this section correspond to the most frequent appearance of clouds when observed 500–1 000 m (1 650–3 300 ft) below their base or above their upper surface, or observed from within.