CLOUDS-ll
CLOUDS-ll
Tropospheric clouds have the potential to influence global climate change. They may deflect incoming solar rays, resulting in a cooling impact where and when these clouds form, or they may trap longer-wave radiation that reflects back up from the Earth's surface, resulting in a warming effect. The major variables that impact the local heating or cooling of the Earth and the atmosphere are the height, shape, and thickness of clouds. Clouds that develop above the troposphere are too few and too thin to have any impact on global warming. The major source of uncertainty in climate sensitivity is clouds.
Nephology
The study of clouds is known as nephology, and it is part of the cloud physics branch of meteorology. The Latin and common techniques for naming clouds at their respective homosphere levels exist.
Etymology
The name "cloud" comes from the Old English terms clud or clod, which refer to a hill or a pile of stone. Because of the resemblance in appearance between a pile of rocks and a cumulus heap cloud, the phrase began to be employed as a metaphor for rain clouds around the beginning of the 13th century. Over time, the metaphoric meaning of the word superseded the literal meaning of the word, which was used in Old English.
Aristotle
Cloud studies in the past were not conducted in isolation, but rather in conjunction with other meteorological factors and even other natural disciplines. Aristotle, a Greek philosopher, published Meteorologica around 340 BC, a book that contained the total knowledge of natural science at the time, including weather and climate. For the first time, precipitation and the clouds from which precipitation fell were called meteors, which originates from the Greek word meteoros, meaning 'high in the sky'. From that word came the modern term meteorology, the study of clouds and weather. Meteorologica was based on intuition and simple observation, but not on what is now considered the scientific method.Nonetheless, it was the first known book to attempt a systematic treatment of a wide variety of meteorological subjects, particularly the hydrological cycle.
Adiabatic cooling
When one or more of three lifting factors – convection, cyclonic/frontal, or orographic – enables a parcel of air containing invisible water vapour to ascend and cool to its dew point, the temperature at which the air becomes saturated, adiabatic cooling occurs. The adiabatic cooling mechanism is the major driving force behind this process. Water vapour condenses to create cloud droplets as the air cools to its dew point and gets saturated. This condensation happens when cloud condensation nuclei, such as salt or dust particles, are tiny enough to be carried aloft by regular air circulation.
One agent is the convective upward motion of air caused by daytime solar heating at surface level. Airmass instability allows for the formation of cumuliform clouds that can produce showers if the air is sufficiently moist. On moderately rare occasions, convective lift can be powerful enough to penetrate the tropopause and push the cloud top into the stratosphere.
Frontal and cyclonic lift occur when stable air is forced aloft at weather fronts and around centers of low pressure by a process called convergence. Warm fronts associated with extratropical cyclones tend to generate mostly cirriform and stratiform clouds over a wide area unless the approaching warm air mass is unstable, in which case cumulus congestus or cumulonimbus clouds are usually embedded in the main precipitating cloud layer. Cold fronts are usually faster moving and generate a narrower line of clouds, which are mostly stratocumuliform, cumuliform, or cumulonimbiform depending on the stability of the warm air mass just ahead of the front.
A third source of lift is wind circulation, forcing air over a physical barrier such as a mountain (orographic lift). If the air is generally stable, nothing more than lenticular cap clouds form. However, if the air becomes sufficiently moist and unstable, orographic showers or thunderstorms may appear
Non adiabatic cooling
In addition to adiabatic cooling, which needs a lifting agent, there are three major nonadiabatic methods for lowering the temperature of the air to its dew point. Surface condensation and fog generation can arise via conductive, radiational, and evaporative cooling, which do not require a lifting mechanism.
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