Lecture 1: Earth's climate introduction and atmosphere Flashcards
Greenland - my notes
Sep 2012- ice decreased dramatically (very fast), its a system of something- the earth is unwell
Greenland, will melt past a threshold all ice will melt
Population predictions vary 8bil-15bil- consequences for the climate
Measurements of greenland ice- towards later years- 2012- all greenland was melting
Mass of ice in greenland- 2000 gig tonnes of ice
CO2 concentration- my notes
C02 concentration- every 100,000 earth come out of an ice age
16th jan 2016- 402.86ppm - C02 concentration - each life time goes up 40- very rapid
Change in surface temp on earth- 2014 highest ever recorded- 2015 to break this record and 2016- something serious is happening
May be facing a mass extinction- famine- war
Recession- drop of co2 decrease in 2015
Climate and earth natural changes - my notes
Climate- interconnecting components
Earth split into - Ocean- Land- Ice- Chemistry- Atmosphere- Vegetation
Natural changes in plate tectonics- Pangea- Antartica was a rainforest
Natural Changes in earths orbit- diff temp- ice can melt- darker areas more warmth
Natural Changes in the suns’s strength- changing over the years
Anthropogenic causes- combustion of fossil fuels and land use change
Where does energy in the earth’s system come from?- my notes
-The sun - almost everything on earth comes from the sun
-Geothermal- volcanic (however, very tiny)
-Not the hottest object in the universe, pretty cool for a star
-Sunspot- not that hot- more sunspots more energy from the sun- areas surrounding sunspot is much hotter
-Galielo- noticed the first sun spots
-50yrs sun didn’t have sunspots- thames freezing over, western summers much colder, mild
-1950-2000= 250 sunspots (peak)- something is happening on the sun
The 11year sunspot cycle has a measurable but small impact on the solar energy output
Humans have a bigger impact on climate change than sun
The electromagnetic spectrum
infrared, visible, ultraviolet- body hotter= shorter wave length= more energy
Sun mostly emitted visible
The sun
Sun is approx. 150 million km from Earth
• 15 million°C at the core,
• 6000 K at the surface (photosphere/chromosphere)
The sun - sunspots and atmosphere
Sunspots are cooler regions (average area of a sunspot is five times the diameter of the Earth)
• The corona (the Sun’s “atmosphere”) is much hotter than the surface but due to its low density it radiates much less energy into space.
• Solar flares can emit large quantities of UV radiation and energised charged particles (magnetic storm)
EMISSION OF RADIATION: PLANCK’S LAW
Planck’s Law describes the amount of energy emitted at a given wavelength at a given temperature
EMISSION OF RADIATION: PLANCK’S LAW- more info
Every object
with a temperature T > 0 K
(0 K = -273.15 oC)
emits electromagnetic radiation.
- A “Black Body” is in the physical sciences a term for an idealised object that absorbs and emits electromagnetic radiation over all wavelengths.
- At room temperature such a body looks completely black to our eyes
- Planck’s Law describes the spectral distribution of emitted EM radiation of a black body at a given temperature.
- Both the Sun and the Earth are approximately like black bodies in terms of their radiative behaviour.
(the sun does not look black to us as it is not at room temperature!)
RADIATION LAWS: STEFAN-BOLTZMANN LAW
M =εσT4
M = total radiant exitance from the surface of a material (watts m-2) σ = Stefan-Boltzmann constant, (5.6697 x 10-8 W m-2 K-4) T = absolute temperature (K) of the emitting material ε = emissivity
RADIATION LAWS: WIEN’S DISPLACEMENT LAW
Wien’s Displacement Law determines the wavelength of the peak of the Planck distribution curve: m a x Tb • b=2897μmK ( constant number) • TinKelvin • Resulting λ in μm (= 10-6 m)
