The phenomenon of Shelf Clouds has recently made the headlines as a massive formation was spotted in Haridwar, Uttarakhand. This article will delve into the nature of Shelf Clouds, their formation, and provide an overview of various types of clouds.
Understanding Shelf Clouds
Also referred to as Arcus Clouds, Shelf Clouds are often linked with potent storm systems. They are sometimes mistaken for wall clouds, funnel clouds, or rotation due to their appearance beneath cumulonimbus clouds – the dense, towering vertical cloud that triggers heavy rainfall. Shelf Clouds precede thunderstorms characterized by intense rain, high winds, and occasionally hail or tornadoes.
In terms of how they form, when a cold downdraft from a cumulonimbus cloud touches the ground, this cold air could quickly spread along the ground, causing the existing warm moist air to be pushed upward. As this cold air descends, it forces the warm air upward, leading to condensation and cloud formation. This process gives rise to the distinct horizontal shape typical of shelf clouds.
Classification of Clouds
Clouds can be categorized into high clouds, middle clouds, low clouds, and clouds that show significant vertical development.
High Clouds include Cirrus, Cirrocumulus, and Cirrostratus Clouds. Cirrus Clouds are high-altitude, wispy, feathery, white clouds composed of ice crystals and usually denote fair weather. Cirrocumulus Clouds appear as small, white, fluffy cloud patches often with a wavy or honeycomb-like pattern. Cirrostratus Clouds form a thin layer covering the sky and can cause halos around the sun or moon.
Middle Clouds consist of Altocumulus and Altostratus Clouds. Altocumulus Clouds appear as white or gray patches or layers often with a wavy or lumpy appearance. Altostratus Clouds form a uniform gray or bluish-gray layer across the sky, thicker than cirrostratus clouds, and often lead to light precipitation.
Low Clouds include Cumulus, Stratus, Stratocumulus, and Nimbostratus Clouds. Cumulus Clouds are fluffy, white clouds typically formed by rising warm air currents and are a common sight on sunny days. Stratus Clouds create a dull, overcast ambiance as they cover the sky in a grayish layer. Stratocumulus Clouds have a patchy appearance, often appearing as rounded masses covering a significant portion of the sky. Nimbostratus Clouds are dark, thick clouds bringing continuous precipitation.
Cumulonimbus Clouds illustrate significant vertical development. These large, towering clouds are linked with thunderstorms, and produce heavy rain, lightning, and strong winds.
Relevance of Clouds in Climate Change Studies
The study of clouds and their characteristics is crucial for understanding climate change. While the common perception is that high clouds reflect solar radiation, thereby cooling the Earth’s surface and low clouds absorb infrared radiation from the Earth’s surface, thus causing warming effects, this isn’t the case. In fact, low, thick clouds predominantly reflect solar radiation, leading to a cooling effect whereas high, thin clouds mainly transmit incoming solar radiation but also trap some outgoing infrared radiation from Earth and radiate it back, causing a warming effect of the Earth’s surface. Therefore, knowledge of cloud dynamics is instrumental in predicting weather patterns and understanding the global climate system.
