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Lecture

GEOG 205 Review Session.docx


Department
Geography
Course Code
GEOG 205
Professor
Gail Chmura

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GEOG 205 Review Session
Ekman transport
o fits into evidence of the warming world
o there has been an increase in colder, nutrient rich waters
o offshore Ekman transport (just in the surface layers) moves water offshore, so the water
replacing that water is from upwelling generally
o nutrients are all settling in the bottom
o there is also onshore Ekman transport, pushing water towards the coast instead the
water is being pushed down as it piles up against the coast
o this process is becoming more prevalent due to increases in wind strength
o winds that are going along the shore are also becoming stronger, and these winds drive
Ekman transport
o the net effect is that the overall mass of the water is moving 90 degrees from the overall
winds
o across the N Atlantic there is offshore so it moves from east to west in a clockwise
motion
o across the S Pacific there is onshore so it moves from west to east in a counterclockwise
o the significance is that stronger winds are driving more of this
o intensifying pressure gradients
o happens at 90 degrees due to friction and the Coriolis effect
anomaly calculations
o you make a baseline so that it is easier to compare values/temperature on a plus or
negative sense
ITCZ = inter-tropical convection zone
o as it shifts it brings rain (specifically to Africa)
o in the past, it shifted & had dramatic consequences who live in modern day Sudan
o it shifted during the Hypsithermal
o the N hemisphere warmed up considerably
o there is a diagram in the reading for this class
o as you warm up the N hemisphere you have lower air pressure which sucks up the ITCZ
o this made Sudan into a desert
o significance is the rains
o what affects its position? you can think of it as being involved in El Nino
o this shows that there processes happening at the ITCZ are not the same as those
happening in the middle of the North American continent such as Minnesota
megafaunal extinction
o the loss of keystone species was one of the effects
o there was an overall recipe of disaster though
o we can blame humans for the extinction of wooly mammoths, but why did all of the
other species go extinct?
o this shows that there must have been something bigger than happened
o keystone species are ecological engineers
o recipe for disaster humans hunting, fires on vegetation, introduction of new species,
climate change, etc.
o the removal of key stone species would also be an ingredient in the recipe of disaster
but you can make an argument out of this
circumpolar current
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