ATMOSPHERIC EFFECT

PRESENTATION BY NASIR ABBAS GOLVI

We will discus about these topics.

Condensation And Precipitation. Air Masses. Storms. Atmospheric Pollution. Climate And Pollution.

Atmospheric EffectsThe lower atmosphere (troposphere) is dynamic,

resulting in frequent weather changesThe movements and interactions of large air

masses bring variations to our weatherLarge air masses can move thousands of miles

and influence a region for a considerable time period

CondensationWater droplets do not

form randomly, but form around microscopic foreign particles called hygroscopic nuclei present in the air

Hygroscopic nuclei may consist of dust, smoke, soot, salt, or other small airborne particles

If the proper type/size of airborne particles are not present, condensation may not occur or will be retarded

Precipitation

When condensation does occur, the tiny droplets are formed in updrafts and are easily suspended as a cloud

Precipitation requires larger drops to form

Two processes are thought to be responsible for the formation of drops large enough to fall Coalescence The Bergeron process

Coalescence – the formation of larger drops by the collision of

droplets

Coalescence

The Bergeron Process The Bergeron process

involves three essential components Ice crystals in the upper

portion of the cloud Supper cooled vapor in

the lower portion of the cloud

Mixing or agitation brings the ice crystals in contact with the supper cooled vapor

Types of Precipitation Precipitation

occurs in the form of rain,

snow,, hail, or fog

Hailstones If the convection cells in the

thunderstorms are powerful enough, hailstones can become quite large

Air MassesAir mass – a large body of air that

takes on physical characteristics that distinguish it from the surrounding air

The main physical characteristics the distinguish an air mass are temperature and moisture content

Storms Storm – an atmospheric disturbance that may

develop within a single air mass or may develop along the frontal boundary of air

masses There re different types of storms.

rainstorms, thunderstorms, ice storms, snowstorms, and tornadoes

Lightning and ThunderA lightning flash travels at the speed

of 300,000 km/s (speed of light)Thunder is a sound and only travels

at a speed of approximately 1/3 km/s

(1/5 mi/s)

Atmospheric PollutionPollution – any atypical contributions

to the environment resulting from the activities of humans

Air pollution is primarily the result of products of combustion and industrial processes that are released into the atmosphere

Releasing waste gases and particulates into the atmosphere has long been practiced

Air Pollution Sources The major source of air

pollution is due to the combustion of fossil fuels – coal, oil, and

gas Increased amounts of

CO2 in the atmosphere lead to increased

acidity Pollution and increased

acidity of the rain results in statues and

other structures undergoing

increased/accelerated corrosion

Pollution and Climate It is generally accepted by most scientists that the global climate is also being affected by atmospheric

pollution CO2 and other “greenhouse gases,”

particulate emissions, and the resulting global cloud cover all affect the Earth’s also

Scientists are trying to understand climate changes by using various models

Climate models give scientists the opportunity to compare theories and use historical data to study the interrelationships between the Earth’s atmosphere and other factors

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