Lecture 19: Atmosphere 1 Flashcards
What is the Atmosphere?
The Gaseous envelope that surrounds a celestial body
What is the Atmosphere comprised of?
A mixture of gases and suspended particles
How does the composition of the atmosphere change as you move upwards?
It thins as you move upward and merges with space at 500 km
What does the Atmosphere do on earth?
Supports and protects life, stores moisture and solar energy and moves earth materials
What kind of Atmosphere did earth have after Accretion and what was its composition?
A primordial atmosphere comprised of hydrogen, helium, methane, ammonia and water
What happened to the Primordial atmosphere of earth?
It was stripped away by solar winds
What formed earth’s secondary atmosphere?
Volcanic outgassing that released volatiles to the earths surface
What was the compositions of the Secondary Hadean atmosphere?
Little or no free oxygen, different proportions of H2O, CH4, H2, CO2, and Argon
How did the Secondary Hadean atmosphere affect earth?
The greenhouse gasses trapped heat and reacted with water to form acid
How was oxygen formed in Early Earth (Archean to Proterozoic)?
Initially O2 maye have formed by ultraviolet light breaking down O2
Later photosynthesis by cyanobacteria oxygenated the atmosphere
What did Iron band formation mark?
Photosynthesis by cyanobacteria oxygenating the atmosphere
What came along with oxygen in the early earth and how did it affect the earth?
WIth O2 came O3 and it absorbed harmful UV radiation making it possible for life to survive in shallow water and on land
How much of today’s atmosphere is oxygen
21%
How much oxygen was in the Hadean and what would it have done?
There was probably little to none and it would have reacted with stuff and been short lived
What is the waste product of Cyanobacteria?
Oxygen
What are the Primary factors measured when studying the atmosphere?
- Pressure
- Temperature
- Moisture (humidity)
What are Radiosondes?
Instruments that are used to measure altitude, pressure temperature, relative humidity, wind speed and wind direction
What do Barometers measure?
Pressure
What are the two types of Barometers?
- Mercury Barometers
* Aneroid Barometers
What is measurement of atmospheric pressure in?
atm where 1 atm is the standard pressure at sea level
How do Aneroid Barometers work?
There is a capsule that can push in or out in response to atmospheric pressure
How atmospheric density change as you move through the atmosphere?
Atmospheric density increases downward and pressure decreases upwards