Modern Atmosphere and Air Pollution

Sunrise from space over the South China Sea. An astronaut would see something like this; clearly defined bands of color through the atmosphere as the sun rises. High-peaking cumulus clouds, topping out in anvil-head cirrus can be seen as black shadows against the sunlit horizon. The brightness of the colors in the atmosphere in this photograph is due to the amount of dust in the atmosphere. More dust is found in near the equator. There are various sources for such upper level dust. Many dust storms in Africa and ash clouds from major volcanic eruptions are two reasons. Courtesy LPI/NASA

Earth viewed from the Moon

Why is the Sky Blue?

The atmosphere protects Earth Surface Cosmic rays are very high-energy particles, mainly originating outside the Solar System. They may produce showers of secondary particles that penetrate and impact the Earth's atmosphere and sometimes even reach the surface. Composed primarily of high-energy protons and atomic nuclei, they are of mysterious origin.

Pressure vs. Altitude

Air density vs. Altitude

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30

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1.2 kg/m7.99 km

hhH

H

Atmospheric Criterion

Homosphere 0-80 kmThe gases are mixed nearly uniformly.

HeterosphereThe gases are not evenly mixed.

Stable Components of the Atmosphere

Atmospheric Temperature Criterion • Troposphere – the region of principal weather

activity, 90% of the atmosphere. The upper limit defined by temperature of -57C.

• The upper layer is called tropopause, 18 km at the equator and 12 km at middle latitude; 8 km at the poles.

The temperature profile of the troposphere

• Normal lapse rate , decrease of 6.4C per km and it is only an average; Standard Atomosphere

• The actual lapse rate is called Environmental lapse rate

Stratosphere • Extends from 18 to 50 km from the Earth’s

surface. • Temperatures increase with altitude up to 0C at

50 km • The stratosphere is layered in temperature

because ozone (O3) here absorbs high energy UVB and UVC energy waves from the Sun and is broken down into atomic oxygen (O) and diatomic oxygen (O2).

Stratosphere

Mesosphere • Between 50 to 80 km • The upper limit the

mesopause is the coldest portion of the atmosphere -90C

• This is due to decreasing solar heating

Thermosphere • Temperatures are rise sharply in the

mesosphere• Thermospheric temperatures increase with

altitude due to absorption of highly energetic solar radiation.

• Radiation causes the atmosphere particles in this layer to become electrically charged (the Ionosphere

Atmospheric Function Criterion • The Ionosphere absorbs

cosmic rays, gamma rays, X-rays and shorter ultra violet wavelengths, changing atoms to positively charged ions

• Extends from 85 to 600 km

Ionosphere and broadcast

:// . 2 . / / /http www windows universe org earth Atmosphere ionosp.here html

Profile of the Atmosphere

Aurora Borealis These two photos show the aurora borealis (Northern Lights) over Alaska in March 2001. The green color of this aurora tells us something about it. The green glow comes from oxygen atoms in Earth's upper atmosphere. Images courtesy of Jan Curtis.

Ozonosphere • The portion of the stratosphere that contains t

an increase level of Ozone.• Ozone is a highly reactive oxygen and absovs

UV 100-300 nm and reradiates this energy in infrared radiation.

• Today it is in situation of continues change• ClO+O3 --->Cl+2O2

• Cl+O3 --->Cl0+O2

Chemical evidence of ozone damage by humans

Vertical profile of the temperature

Space Diving

The big jump in HistoryFelix Baumgartner

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Speed of the Jump