16.WATER IN ATMOSPHERE..
Water is present in variable amounts in the atmosphere, from 0 % to 4 %. … In the atmosphere, water exists as a gas (water vapor from evaporation), as a liquid (droplets of rain and liquid water that coats solid particles), and as a solid (snow and ice). The movement of water in the atmosphere can be explained through the following processes.
▪️ evaporation: it is a process by which water is transferred from liquid to Vapour from gaseous state due to an increase in temperature and decrease in pressure.Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide with each other. Water boils at 212°F, begins to evaporate at32°F. The temperature increases the rate of evaporation also increases. Water vapour are carried by hot Air into the upper layer of the atmosphere.
▪️condensation:
Description
Condensation is the change of water from its gaseous form (water vapor) into liquid water. Condensation generally occurs in the atmosphere when warm air rises, cools and looses its capacity to hold water vapor. As a result, excess water vapor condenses to form cloud droplets. As these water vapour rise upwards the temperature reduces.reduction in temperature transfer the water vapour into water. Process of transformation is called condensation. it is caused on account of loss of heat by the water vapour.
▪️ sublimstion:if the drop in temperature of air is so large that the water vapour is directly converted into ice it is called sublimation.The reverse process of sublimation is deposition or desublimation, in which a substance passes directly from a gas to a solid phase.[3] Sublimation has also been used as a generic term to describe a solid-to-gas transition (sublimation) followed by a gas-to-solid transition (deposition). Both condensation and sublimation lead to precipitation.
🔸️Other outcomes of condensation of sublimation.
▪️dew:
Description
Dew is a natural form of water, formed as water vapor condenses. Dew, like the glistening drops on this grassy field in Anaconda, Montana, forms as water near the surface of the ground is cooled to its dew point, the temperature at which water vapor condenses. it refers to the droplet of water on the surface of cold object there is a sudden reduction in the temperature of form here this sudden reduction and temperature causes condensation of water vapour present in warm air
▪️Frost:
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor to ice as the water vapor reaches the freezing point. Frost refers to the Ice crystal on the surface of cold object. These crystals emerge when moist air comes in contact with very cold object which is below freezing point. Frost occurs when sublimation takes place.
▪️fog:
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth’s surface. Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. When the cold surface of earth comes in contact with the layer of warmer fog appears.
🔸️Types of precipitation: precipitation occurs on account of condensation and sublimation of water vapour brought upwards by Convection currents. various form of precipitation are as follows…
1snowfall:a fall of snow specifically : the amount of snow that falls in a single storm or in a given period.
2.Hail:
Hail is a type of precipitation, or water in the atmosphere. Hail is formed when drops of water freeze together in the cold upper regions of thunderstorm clouds. water droplets freeze into Ice and fall on the earth surface..
3.sleet:
Sleet is rain or melted snow that freezes into ice pellets before hitting the ground. Sleet only happens under very specific weather conditions. slet occurs when the surface temperate of the Earth is lower than the temperate and the upper layer of atmosphere.
4.rainfall:
Rainfall is measured using rain gauges. Rainfall amounts can be estimated by weather radar. Rain is also known or suspected on other planets.
Precipitation can be classified into three types on account of its origin:
<1> conventional rainfall: this type of rainfall occurs when warm moist air undergoes condensation after rising. These type of rainfall mostly occurs during daytime and particularly in the late afternoon because the convection current are are strongest during the afternoon on account of high heat raise from the Sun.
<2>. Orographic or relief rainfall:
Orographic or relief rainfall is caused when masses of air are forced up the side of elevated land formations, such as large mountains (often referred to as an upslope effect). The lift of the air up the side of the mountain results in adiabatic cooling, and ultimately condensation and precipitation. This type of rainfall occurs when passing warm moist air is forced To rise due to presence of mountain. The windward side of mountain receives a large amount of rainfall, whereas on the leeward side there is lesser rain as the air has already shed its moisture on the windward side.
<3>. Cyclonic or frontal rainfall.
Cyclonic Rainfall is convectional rainfall on a large scale. … type while that in a temperate cyclone is because of frontal activity. This type of rainfall occurs when warm and cold air air masses come in in contact with each other when the cold air mass come in contact with the warm air mass the water vapour present in warm air experiences condensation and there is rainfall. Rainfall is called frontal rainfall. Cold wind settle at the bottom and push warm wind upwards. As worm wind move upwards the undergo condensation and thus rainfall occurs.these types of rainfall occurs at the temperate low pressure belt. In this region cold polar easterlies meet warm westerlies.
