Wicked Flashcards
On a large scale, throughout Earths history, where does extreme variability in temperature come from?
Solar forcing mechanisms
What is the Milkanovitch Theory
The Serbian scientist from the 1920s theorized that there were subtle changes in earths energy budget due to orbital changes around the sun
What does the ice-albedo feedback loop state?
Diminished incoming solar radiation at northern latitudes would increase snow and ice, which increases the earths albedo, which increases the snow and ice in northern latitudes
What are the three main reasons for the formation of the ice-albedo feedback loop?
- Changes in the earths tilt
- Changes in the earths orbit
- Changes in the precession of the earths orbit
Earths tilt is also called? What is the earth tilt today?
Obliquity
23.5 degrees
Over time, how much has the earths tilt varied in degrees
22-24.5
If we increase the earths tilt, what would occur with solar radiation?
Increasing the earths tilt increases the intensity of solar radiation in the Northern Hemisphere
How does maximum and minimum tilt affect the winter and summer temperatures in the northern hemisphere?
maximum tilt in the NH, summers are very hot
minimum tilt in the NH, winters are very cold
How would minimum tilt affect the ice albedo affect
Since minimum tilt makes winter colder in the northern hemisphere, less solar radiation will be emitted, which increases the snow and ice, which increases the earths albedo even more, and incresaes the snow and ice more
Variation between the maximum and minimum tilt is a period of ___ years?
41,000 years
Earths Orbit is also called
Eccentricity
The earths eccentricity varies over a ___ year period? What does it mean for the orbit to have more or less eccentricity?
100,000 year period
more eccentricity = more elliptical
less eccentricity = less elliptical
Would high eccentricity mean more or less round?
High eccentricity = more elliptical
Low eccentricity = more circular
15 ka BP, the orbit was much more ___?
Eccentric
When will the orbit be eccentric again
what will be changed in the orbit to make the eccentricity occur
85 ka years
Perihelion will be smaller
Aphelion will be longer
Currently the difference in solar constant at perihelion and aphelion is ___? How will this number change during maximum eccentricity?
7%
During maximum eccentricity, this percentage should be much larger
What is precession with respect to the earths rotational axis?
The top of the top begins to trace a small circe in respect to the central axis as the earths rotation axis is not fixed in space
Currently, the earths central axis points towards the ____?
North Star, Polaris
in 13,500 years, the tilt of the earths axis will be toward ___? How will this alter the seasons?
Vega - altering the timing and intensity of the seasons
What is the time period for precession?
27 ka years
Which day of the year is aphelion vs perihelion
Aphelion - July 21st
Perihelion - December 21st
How will Saskatoons tilt be different in 13,500 years?
Saskatoon will tilt toward the sun in january and away from the sun in July
Summers will be cooler and winter will be warmer (because in january, at the perihelion, we are closest to the sun)
Milankovitch thought that any of the three processes, or any combination of two or more could start a ___?
ice age
Unfortunately, nothing mathematically lines up with the ice age cycles we know occured
Since the Milankovitch theory does not perfectly align with the glacial/interglacial cycles of an ice age, what are the other climate forcers?
- Variation in solar output
- Changes in land configurations and surface characteristics
- Changes in atmospheric turbidity
A. Tropospheric aerosols
B. Stratospheric aerosols
