Which of the following can be used to determine the height of the sky cover?

The determination of sky cover height is an important aspect of weather observation, and multiple tools and methods can effectively provide this information. A ceilometer is a device specifically designed to measure the height of cloud bases. It emits a light signal upward and then measures the time it takes for the light to reflect off the cloud and return, allowing for an accurate reading of cloud height.

A ceiling balloon is a tool where a balloon is released and ascends until it reaches the cloud layer. By measuring how high the balloon rises before it encounters cloud cover, one can determine the height of the clouds. This method can also be useful for providing visual observations during daylight.

Observer experience plays a crucial role in weather observation as well. Trained observers can estimate cloud heights based on visual cues and their understanding of meteorological conditions. With practice, they can approximate the heights of clouds and assess sky conditions effectively.

Given that all three methods – the ceilometer, ceiling balloon, and observer experience – contribute valid and reliable means of determining sky cover height, the selection of all the above as the answer encapsulates the comprehensive approach to this observational task. Each method has its strengths and can be applied in different scenarios to ensure accurate weather assessments.