Metoerology Presentation

METEOROLOGY PRESENTATION
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(21 July 2011)
Meteorology Presentation
The formation of clouds usually occur after water has evaporated into vapor from large water bodies like lakes, oceans, ponds and even by evapotranspiration over earth’s land surface which then condenses in the atmosphere. Meteorologists have however named clouds depending on how high they are in the sky and how they appear. This essay describes in detail different types of clouds.
The first type of clouds is cumulus, which have been described as being low clouds with a type base of not more than 7,000 feet. They are usually described as being puffy or having cotton appearances, apart from appearing alone in either lines or clusters. They are mostly precursors of other cloud type like cumulonimbus, when other factors like instability, moisture and temperature gradient occur. They are usually part and parcel of cumuliform category which comprises of cumulus congests as well as cumulonimbus clouds among others. These cumulus clouds that are much intense are associated with severe weather phenomena like hail, tornadoes along with waterspouts.
Cumulus clouds are typically formed when warm air rises to a level of cool air, where there is condensation of moisture in the air. Ackerman and Knox, (2003) States that, “this happens through convection, where a parcel of air is warmer than the surrounding air. As it rises, the air cools at the dry adiabatic lapse rate (approximately 3°C per 1000 ft or 1°C per 100 m), while the dew point of the air falls by 0.5°C per 1000 ft. When the temperature of the air reaches the dew point, some water condenses out of the air to form the cloud,” (Ackerman & Knox, (2003). The cloud’s size relays much on profile of temperature as well as the inversion presence. Incase the cloud’s top reaches the altitude where temperature is bellow freezing point, there are possibilities of precipitation from cumulus clouds. However, it is the ground’s level temperature that determines if precipitation will be inform of rain or snow. When weather conditions are windy, such cloud will form lines which are usually parallel with the winds directions. Areas with mountains will also experience cumulus clouds having lines inclined at the wind’s angle as a result of lee waves above such clouds. Over the sea, these clouds have patterns or spaced lines. The winds between cloud lines are much stronger, gusty and veering; while beneath the cloud lines, the winds are somehow lighter and more backing.
The altitude at which clouds start forming depends on the moisture amount in air, like in humid regions, clouds have a lower base. In temperate areas, cumulus clouds’ base is mostly 8 000 feet, while in arid and mountainous areas, the cloud’s base can be higher than 20, 000 feet. Pilots have been for many years paying close attention to Columbus clouds as they indicate rising air drafts. The figure 1 bellow shows a photo of atypical cumulus clouds.


Figure 1 showing Columbus. Source: http://australiasevereweather.com/techniques/moreadv/class.htm
Another type is cumulonimbus; this is another towering vertical cloud that is considered as being very tall, dense and results to thunderstorms and other inclement weather. the name was derived from ‘cumulus’ meaning accumulated and ‘nimbus’ meaning rain. It is due to atmospheric instability. There are different forms through which cumulonimbus clouds, namely, alone, in a cluster or even along cold front in a squall line. In most cases, they have the ability of creating lightening through the cloud’s heart. They are usually formed from cumulus clouds particularly from cumulus congestus, which further develops into supercells that results to thunderstorms along with other special features that can be described as being severe.
This type of cloud has several layers, namely; the anvil and downdraft. the upper part that is a flat layer is called Anvil, while the rain area to the right is known as downdraft. This clouds in most cases originates from Columbus coop at a lower altitude, which makes them look like Columbus clouds, however, they usually grow vertically instead of growing horizontally. This explains the reason as to why cumulonimbus clouds have a mushroom shape. Its base can be many mil...