Table of Contents
Introduction
Clouds are made up of ice crystals or water droplets, typically light and small that they are easily suspended in air (Logan et al., 2014). There are different types of clouds with distinct names based on their height in the sky and their shape. Clouds are associated with various hazards which can pose significant risks to the aviation industry, and thus aviators should obtain appropriate weather forecast before and during the flight (Chartwell, 2016). This research seeks to describe the process of cloud formation, discuss different types of clouds, identify various types of hazards associated with clouds and illustrate the impacts of these hazards to the aviation industry.
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Process of cloud formation
Clouds constitute of the ice crystals or water droplets that are so light and small that they are easily suspended in air (Chartwell, 2016). Ice and water droplets in the form of clouds easily move into the sky in the form of water vapor. Water vapor moves into the atmosphere mostly by the process of evaporation. Liquids from the lakes, oceans, rivers and other water bodies evaporate into the air forming water vapor (Logan et al., 2014). Water vapor entails water in the gaseous form that is in the atmosphere is under low pressure and gets cooler with time. Air in the atmosphere cannot hold much water especially because it is cool and the pressure has reduced. The vapor converts into ice or small water droplets and thus clouds are formed (Chartwell, 2016). Water vapor condenses faster into ice and water droplets when there are other particles around. For instance, the presence of dust particles and pollen makes water condense more quickly and thus the cloud is formed easier and quicker. A particle such as dust and pollen are referred to as condensation nuclei (Chartwell, 2016). As such, clouds can be formed of a mixture of ice, water droplets, and pollen or dust particle.
Some cloud may be formed when warm air close to the ground rises after being heated by the sunshine and warm ground that has been heated by the scorching sun (Logan et al., 2014). The heated air is lighter and less dense and then the air found around it, and thus it easily rises. Temperature and pressure decrease as the air rises. The raised air condenses to water vapor. Water vapor condenses to ice and water droplets as it moves upward. Examples of clouds formed in such as process include cumulonimbus, stratocumulus, and cumulus (Chartwell, 2016). Other clouds may be formed when brisk wind flow towards higher terrain or mountain ranges and thus forced higher in the atmosphere. The side of the upper terrain or the mountain that the winds blow towards is referred to as windward side (Logan et al., 2014). There is always one side of the mountain where the wind blows away and is known as the leeward side. It is not a must that there is a mountain around for air to cool. Air can cool to form clouds any time it encounters a slope forcing it to rise and cool (Chartwell, 2016). Cumulus clouds can also be set up in the mountain as warm air rises after being heated.
Types of the clouds
Clouds are given distinct names based on their height in the sky and their shape (Cornish et al., 2014). Some clouds are formed very high in the sky while other are found near the ground. Cloud may be classified into three broad categories depending on the position they occupy in the sky. The broad categories include high, mid and low clouds.
High clouds include cirrus, cirrostratus, and cirrocumulus (Cornish et al., 2014). Cirrus is the types of cloud that is almost detached forming narrow bands of white patches or delicate filaments. It appears silky sheen and hair-like fibrous substances. It is made up of ice crystals that are transparent depending on the degree in which particles are separated. The Sunshine does not diminish when the cloud has covered the sky (Götz, 2012). Cirrostratus is transparent, white fibrous veil-like cloud that also appears smooth. Cirrostratus is extensive and covers almost all the sky with a white veil and allows the moon or the sun to be visible but not as clear as Cirrus would allow. Cirrocumulus is the thin sheet of white layered cloud that does not form the shade. It is made up of very small elements and is almost regularly arranged (Cornish et al., 2014). Cirrocumulus characterizes the degraded state of cirrostratus and cirrus and demonstrates features of ice crystal clouds.
Mid clouds include nimbostratus, altostratus, and altocumulus (Cornish et al., 2014). Altostratus is bluish or gray sheets or layers of striated clouds that appear fibrous in nature. Altostratus cloud partially or totally covers the sky and is so thin that the sun can be visible. Altostratus cloud does not shadow of objects or produce halo phenomenon. Occasionally, the cloud can reach ground level leading to the formation of very light precipitation (Götz, 2012). Altocumulus is a gray or white patch sheet consisting of layered cloud with forming laminae or plates which appear like rolls or rounded masses. It may be diverse or partly fibrous, and the sun or the moon would appear when the cloud forms thin or patchy surface. Altocumulus is the most frequently appearing type of mid clouds and may be included at distinct levels at the same period (Cornish et al., 2014). Nimbostratus constitutes perpetual rain cloud that is the product of thickening altostratus. The cloud has dark gray color, and its layer diffuses by falling snow or rain.
Low clouds include cumulus, stratus, cumulonimbus and stratocumulus (Cornish et al., 2014). Cumulus constitutes of detached dense cloud, developing vertically, has characteristic sharp outlines and is in the form of rising mounds. Cumulus from towers or domes with protruding upper parts and has flat and relatively dark bases (Götz, 2012). Mostly, it develops during the days of clear skies, appears during the early hours, and then disappears later in the evening. Stratus is typically gray cloud with uniform base and mostly thick enough to yield drizzle, snow grains and ice prisms. When the layer of stratus dissipates and breaks up the blue sky is clearly visible (Cornish et al., 2014). Cumulonimbus entails huge, dense, heavy cloud resembling a tower or a mountain commonly referred to as thunderstorm cloud. The upper part of cumulonimbus is fibrous smoothed or striated, nearly flattened forming the shape of an anvil. The base of the cloud is dark and constitute of small ragged clouds that sometimes merge with the base (Götz, 2012). They yield precipitation and are capable of producing produce tornadoes and hail. Stratocumulus is the gray cloud with white sheets or patches with many layers and is always dark in appearance. Mostly, the cloud does not merge and are occasionally non-fibrous (Cornish et al., 2014). The cloud forms small elements that are regularly arranged forming width that is slightly more than five degrees.
The hazards of clouds
Stratocumulus cloud is among the most common. It serves good indicator of the presence of moisture entire lower levels earth atmosphere (Duarte et al., 2016). Stratocumulus cloud may be deep and wide vertically, a clear indication that they are capable of hiding embedded thunderstorms. All thunderstorms may lead to the production of severe turbulence, low ceilings, low-level wind shear, visibility challenge, lightning and hails (Kirk, 2013). These hazards pose challenges to aviation industry because they are difficult to overcome. When all the above conditions arrive concurrently, they can be disastrous. Stratocumulus can also hide high terrain or mountainous ranges. Stratocumulus cloud occurs between 2,000 to 6,500 feet, above the ground level (Duarte et al., 2016). It has the characteristic ragged appearance on the upper surface and well-defined flat base. Hiding terrain and presence of embedded thunderstorms is the huge threat to the aviation industry especially on low flying aircraft. Besides, Stratocumulus tends to form in comparatively shallow layers, sometimes several hundred miles wide.
Cumulonimbus is one of the most hazardous clouds because it leads to the formation of heavy precipitation, tornadoes, and hail. Cumulonimbus clouds are usually large clouds that may be found beyond 20,000 feet above ground level. Extreme cases of presence of cumulonimbus can go up to 60,000 feet above ground level. As such, pilots operating general aircraft may find it impossible to fly around or above them. The presence of Cumulonimbus can thus be very hazardous to aircraft. When a tornado is being formed, air is drawn into their cloud bases violently creating enormously concentrated vortex connecting the cloud to the ground. It is estimated that the wind moves at a speed of more than 200 knots at relatively low pressure.
Debris and dust are gathered from the ground at low pressure generating a cloud that takes appear like a funnel extending to the base of the cumulonimbus cloud (Duarte et al., 2016). The cumulonimbus cloud directly connected to the severe thunderstorm may be extremely violent and thus a significant threat to surface structures and aviation. Frequently, cumulonimbus clouds occur in association with awful tornadoes and intense thunderstorms (The United States, 2013). The cloud appears rounded in shape with festoons from the base and irregular pockets which form the indication that the outcome will be violent turbulence. Aircraft entering the vortex is most likely going to sustain structural damage (Kirk, 2013). The Severe Thunderstorm also leads to the formation of hidden vortex that could be harmful to the aircraft.
Hazards to Aviation industry
Clouds possess various hazards and can be very destructive to aviation (Kirk, 2013). Squall lines constitute a narrow band and non-frontal of powerful thunderstorms that frequently develops ahead of the cold front in an unstable and moist air. It contains severe steady-state thunderstorms, and thus it has been singled as the most powerful weather threat to aircraft (Houze, 2014). Hail constitutes supercooled drops beyond the freezing point that have begun to freeze and formed one of the greatest threats to aircraft. Supercooling refers to the phenomenon where water remains liquid at the temperature that is below the standard freezing point (Duarte et al., 2016). The hailstones grow into a huge ice ball that is accompanied by severe thunderstorms building up to great heights. When hailstone falls below the melting point, it melts and falls as rain or hail. Hail with the thunderstorm is noticeable beneath towering cumulonimbus. It forms enormous hailstones whose diameter is slightly larger than half of an inch and capable of damaging an aircraft in a very short time (Houze, 2014).
Icing results when water vapor goes above freezing point making water to be supercooled. The temperature in the rising current cool to negative 15 degrees Celsius making the water vapor that remains to sublime forming ice. Ice accumulates rapidly and moves to greater heights with temperature as low as negative 20 degrees Celsius. The aviator should equip themselves with real-time weather information that outlines the global forecast of the expected changes (Kirk, 2013). Frozen supercooled water has the destructive effect to the aircraft and especially when accompanied by thunderstorm icing. Hazardous turbulence occurs in every thunderstorm. The strongest turbulence occurs within the cloud and with shear between downdrafts and updrafts and can be a huge threat to aviation (The United States, 2013). Maneuvering in turbulence increases stresses to the aircraft, and the pilot cannot endure unless the aircraft is maintained at constant attitude so as to ride the waves.
Correspondingly, Cumulus clouds are puffy white clouds that have been created by water droplets in the form of liquid near the surface (Duarte et al., 2016). They vary in size and height depending on the instability of the atmosphere, are separate and do not yield any rain. However, pilots may be deceived by their appearance, but they are capable of forming turbulence. They also limit visibility more than cirrus clouds would do and thus the pilot should be careful while navigating between them (Houze, 2014). Cirrus clouds may have supercooled water droplets that have the ability to cause icing. The pilot is advised to fly around them. At the same time, cirrus clouds limit visibility and thus may be a huge threat to pilots especially for pilots operating aircraft that utilize instrument flight rules airspace (Duarte et al., 2016). Precipitation static constitutes high-level steady noise created by radio receivers that are as a result of intense corona discharge from both at the edge of flying aircraft and sharp metallic points. It is common in the vicinity of thunderstorm each and every time the aircraft pass through cloud’s concentrated solid particle and falling precipitation (Houze, 2014). The charge of static electricity is accumulated in the nearby surface, and surrounding air is triggering noisy at low frequencies leading to disturbance.
Ceiling entails the height above the ground level that the lowest layer of cloud or water is reported (Houze, 2014). The ceiling is obscured if the clouds exist but not distinguishable due to obscuring phenomenon. The ceiling can hinder visibility, and thus it must be evaluated before the aircraft takes off. Visibility and ceiling determine whether the aircraft is capable of comfortably move in and is open to traffic (Duarte et al., 2016). The aviator should be able to see at least three miles, and the ceiling should be at least 1000 feet above the ground level. Hindrances to visibility are due to the presence of precipitation, clouds, dust, fog, snow, smoke and other debris present in the aviation route (Kirk, 2013). Visibility and ceiling can interfere with flight operation a subsequently lead to catastrophic consequences.
Conclusion
Clouds constitute of the ice crystal or water droplets that are so light and small that they are easily suspended in air. They are formed when water on the surface of the earth evaporates and cool as it rises into the atmosphere. The vapor converts into ice or small water droplets and thus clouds are formed Some cloud may be formed when warm air close to the ground rises after being heated by the sunshine and warm ground that has been heated by the scorching sun. There are different types of clouds which can be found formed very high (cirrus, cirrostratus, and cirrocumulus), mid (nimbostratus, altostratus, and altocumulus) and lower (cumulus, stratus, cumulonimbus and stratocumulus) regions. These clouds have some distinguished features to the extent that they appear distinctly different. Clouds may cause hazards mostly through embedded thunderstorms, ice, tornadoes, hail, low ceilings, wind shear and heavy precipitation. Such hazards have adverse consequences to aviation including interference with visibility, interference with radio receivers and destructive effects caused by frozen and supercooled water. Moreover, maneuvering in turbulence increases stresses to the aircraft and the pilot cannot endure unless the aircraft maintained at constant attitude so as to ride the waves. These hazards pose challenges to aviation industry because they are difficult to overcome. When all conditions arrive concurrently, they can be disastrous.
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