Weather and the Atmosphere

Meteorology– Weather – Study of atmosphere at a given time and place, due to unequal heating of Earth’s surface Study of atmosphere and the weather

The Atmosphere

COMPOSITION OF TODAY’S ATMOSPHERE 78 % Nitrogen 21 % Oxygen 0.90 % Argon 0.03 % Carbon Dioxide Traces of other gases, including water vapor (gas form of water)

Composition of the Atmosphere ESRT Page1

How Did The Atmosphere Form?

The Earth’s First Atmosphere EARTH (roughly 4.5 Billion years ago) To space Hydrogen Helium

500 Million Years or So Later

OUTGASSING – release of methane, ammonia, Water Vapor, Carbon Dioxide and Nitrogen when the earth was cooling that made up Earth’s earlier atmosphere

Earth Cooled and Water Vapor Condensed to Form Oceans

Most of the carbon dioxide dissolved in the newly formed oceans and … then combined with other substances to form carboniferous sedimentary rocks (limestone and dolomite).

Nitrogen Chemically inert It remains in the atmosphere

Where did the oxygen come from?

CYANOBACTERIA – Found in Stromatolites

Cyanobacteria Simple bacteria doing photosyntheses and releasing oxygen into the atmosphere Over a billion years, the atmosphere began to change

Evidence Banded Iron Formation – oxygen rusted iron in the sea, dates back 3.5 billion years Red Beds – rusted beds on land, dates back 2.3 billion years

700 Million Years Later With most of iron on Earth’s surface rusted… …oxygen levels built up rapidly

A Few Million Years Later Some of the oxygen was converted into Ozone (O 3 ) a protective layer in stratosphere for life to develop on land

Now Earth Forms, H & He Atm. Outgassing- Carbon Dioxide, Water Vapor & Nitrogen Banded Iron formations Red Bands Evidence of increase in oxygen Cyanobacteria First appear – oxygen added to atm. Formation Of Ozone Layer 78 % Nitrogen 21 % Oxygen 0.90 Argon 0.03 Carbon Dioxide Trace gases

Formation of Oceans Large amounts of water vapor from early volcanoes eventually condensed Condensation fell as rain which eventually formed our oceans Comets may also have contributed to the water on the Earth

Layers of the Atmosphere ESRT Page14 Stratosphere – Ozone layer Troposphere – Where the weather happens

“pauses” Where layers of atmosphere are separated. Temperature will change at the pauses (increase to decrease OR decrease to increase)

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