Lecture 3- Physical Environment II Flashcards
What is Milankovitch cycle?
Changes in glacial and interglacial periods are driven by the patterns of Earths circling of the sun
Name the three components of Milankovitch cycle
- Eccentricity
- Axial tilt
- Precession
Differentiate glacial and interglacial
Glacial= covered by glacials
Interglacial= between glacial periods, not much glaciers
What is eccentricity?
Shape of the Earths orbit around the sun
How does eccentricity influence glaciers?
Prime importance to glaciation because it alters the distance from the Earth to the sun
Eccentricity leads to _______ changes
Seasonal
What are the differences between a circular path and a oval path (eccentricity)
Circle= more even temperature in seasons
Oval= further from sun or closer to sun for part of the year, can drive seasonal changes
What role does axial tilt have on solar radiation?
Less axial tilt results in solar radiation more evenly distributed between winter and summer (causes less seasonality)
Why would decreasing axial tilt promote glaciation?
A warmer winter means warmer air which holds more moisture and more snowfall (as long as you have more snowfall than melting then you’ll get glaciation
What is precession?
Earths slow wobble as it spins on axis
How can precession lead to glaciation?
Can change how much sunlight is experienced across planet which could lead to colder temperatures which could lead to accumulation of snowfall
What could trigger an ice age?
- Milankovitch cycles (changes amount of sunlight)
- Amount of summer sun in the northern continents (if not enough sun, then snow doesnt melt)
Milankovitch cycles explain ______ term changes in the climate
Long
Climate change is more likely impacted by _______ then Milankovitch cycles.
Greenhouse gases
Give in order of warming potential some greenhouse gases
CO2, methane, nitrous oxide, sulfur hexafluoride, water vapour
True or false? Greenhouse gases are naturally occurring and form important parts of cycle
True
Why is water vapour a greenhouse gas?
Because warm air can hold more moisture, stay trapped in atmosphere, reflect radiation back down
What is warming potential?
Ability to absorb radiation overtime
What happens to incoming solar radiation?
- Bounces back into space
- Absorbed in atmosphere
- Absorbed at Earths surface
- Trapped within atmosphere (greenhouse gases)
- Earth can emit some solar radiation back as weaker infrared radiation
Describe northern climates
- Strong seasonal variation
- Short, moderately warm and moist summers
- Long, extremely cold and dry winters
- Highly variable at same latitude
What are the driving factors of changes in climate?
- Solar radiation (because axial tilt)
- Precipitation
What is the solar radiation like at high altitudes?
Hits Earth at an angle, therefore spread over a large surface and more scatter
Climate patterns depend on what?
Depend on warming energy from the sun
Why is solar radiation the most significant driver of northern climates?
- Because of axial tilt
- Travel longer distances, loss of some intensity
- Angle= spread out over larger area, weakens affect, not as effective as warming, diffuses a lot in atmosphere
