Identify the type of cloud on the basis of the given characteristics: 1. High, thin, puffy white clouds of ice crystals that look like ripples 2. They appear between 20000 feet and 40000 feet above the Earth's surface 3. One of its types is called a 'mackerel sky' because the clouds resemble large fish scales, especially when they are coloured pink at sunset.

The characteristics described identify Cirrocumulus clouds. These are high-level clouds found at altitudes between 20,000 and 40,000 feet [3]. Composed primarily of ice crystals, they appear as small, white, puffy cloudlets arranged in ripples or waves [3]. A distinctive feature of cirrocumulus is the 'mackerel sky' pattern, so named because the undulating rows resemble the scales of a mackerel fish [3]. While altocumulus clouds can also form a mackerel sky, they are middle-level clouds (6,500–20,000 feet) and consist largely of water droplets rather than ice crystals [2]. Cirrocumulus clouds are distinguished from other high clouds like cirrus (which are wispy/feathery) and cirrostratus (which form a veil-like layer) by their grainy, 'heap-like' or puffy appearance [2]. At sunset, these high-altitude ice crystals often reflect vibrant pink or red hues [3].

Sources

1. [1] https://en.wikipedia.org/wiki/Mackerel_sky
2. [2] https://www.weather.gov/media/lmk/soo/cloudchart.pdf