Cloud Classification Questions and Answers

Answer: A

Correct answer: the rising air spreads out on reaching a stable layer

The updraught rises until it reaches the tropopause, where the temperature stops falling with height and the air is no longer buoyant. Unable to rise further, it spreads horizontally, and the strong upper winds draw the ice cloud downwind into the characteristic anvil. The flatness of the top marks the tropopause directly, which is why an overshooting top above it is a sign of an exceptionally strong updraught.

Answer: B

The sequence runs through the low, middle and high étages in turn and ends at the ceiling that bounds them. Only cumulonimbus routinely spans the whole of this range in a single cloud. Its base sits with the stratus and its top with the cirrus above.

Answer: C

They are treated as a special cloud of human origin rather than as a genus of their own. Where one persists and spreads it may eventually be reported as cirrus, which is a genuine genus. The category also covers cloud formed above industrial cooling towers.

Answer: D

Correct answer: stratus in contact with the ground

Fog is not a separate genus: it is stratus whose base has reached the surface, and the classification treats it as such. The definition is a matter of position rather than composition - the same cloud is fog to someone on a hilltop and stratus to someone in the valley below.

Answer: A

Cumulonimbus is a genus, whereas the other three are varieties describing how a cloud is arranged or how much light it transmits. Varieties sit at the bottom of the hierarchy. Genus, species and variety together describe a cloud with some precision.

Answer: B

The first two are correct and describe the standard practice using oktas. The third omits the layer reporting that makes the observation useful for aviation and for forecasting alike. A single total would hide a broken low deck beneath a solid high one.

Answer: C

Clouds made only of liquid droplets are warm clouds.

In cloud physics a warm cloud lies wholly at temperatures above 0°C, so it contains only liquid water, and its rain forms by collision and coalescence of droplets. Clouds that reach below freezing are cold clouds, where ice crystals grow at the expense of supercooled droplets (the Bergeron-Findeisen process).

An ice cloud, such as cirrus, is made of ice crystals; a mixed phase cloud holds both supercooled water and ice; and 'cold cloud' is the general name for clouds with ice processes. None of these is made solely of liquid water.