Physical Environment of the Boreal-Arctic Region Part 2
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What are 2 implications of northern areas having long, cold winters and short summers in regards to productivity?
• no primary production in winter –> energy stores need to remain in the area • huge productivity burst in summer –> migrants can capitalize on summer productivity
Insolation=
total amount of solar radiation per unit of time and area
The tilt of the earth’s rotational axis and its spherical shape make the __ ___ ____ of sunlight uneven at diff latitudes
angle of incidence
The average annual temp of northern boreal forests is below __C, and there’s a range of up to __C in seasonal temp extremes. What results in less extreme variation?
5 100 where oceanic climates prevail (eg eastern canada) b/c the water moderates climate
Temperatures vary __(more/less) in the northern hemisphere where the moderating influence of ___ is less
more water more land mass in N hemisphere
___% of incoming sunlight is absorbed by the surface, and most of that is absorbed by ___
45 plants
The amount of solar radiation absorbed by the surface depends on what’s on the surface– ___ absorb the most
plants
amount of solar radiation absorbed by air follows a ___ proportion of the incoming radiation
fixed
light reflected by clouds is ___ in the temperate regions due to dense
higher clouds
Reflection by the surface s highest at ____, but more in ___ than in ___ because of ___
poles Antarctica Arctic snow
why is snow blindness more of a concern at higher latitudes?
because the sun is coming at you horizontally! due to tilt/ angle of incidence
Historic UV radiation was low in arctic– it is rising b/c of ___ How could this destabilize communities?
ozone depleting warming UV can damage DNA & retinas
How does ozone loss differ in Antarctic vs arctic?
Antarctic: almost complete removal of lower-stratospheric ozone currently results in an ozone hole every year Arctic: ozone loss is highly variable and has until now been much more limited
The ozone layer protects us from ___ ___ is important for photosynthesis, and ___ is damaging
UVb UVa (good) UVb (bad)
The climate pattern on earth ultimately depends on __ received from the ___ which warms the land and seas
energy sun
Redistribution of solar energy depends mainly on ____ ____ and ocean ____, which is driven by the ____ of the earth and the position of the continents. This in turn influences ___ patterns
prevailing winds currents rotation precipitation
Light energy coming in at high latitudes: • hits earth at an ___, so energy spreads over a large ___ • hit ____ at an angle, so more energy is ___ back to space
angle surface atmosphere reflected
at high latitudes, more energy is ___ than ___, resulting in a net ___. Near the equator, more energy is ____ than ___, resulting in a net ___
more emitted than gained cooling more gained than emitted warming
climate conditions are divided into 2 subtypes: 1. 2
• maritime: coastal areas where ocean moderates climate= less variation • continental: much lower precipitation and greater contrast b/w summer and winter
Why would somewhere on Norway’s coast have milder winters than a town in NWT? Note they’re at the same latitude
more ocean warming in Norway than in canada= moderates temps
summer temp in Norway vs NWT is very similar compared to their different winters. Why?
b/c ocean doesn’t have as much of an influence in moderating climates in the summer - summer temps influenced more by sunlight
Hadley cell is from __ deg to __ deg Ferrell cell is from ___ deg to ___ deg Polar cell is from ___ deg to ___ deg
Hadley: 0 to 30 Ferrell: 30 to 60 Polar: 60 to 90
What is the North Atlantic Oscillation (NAO)?
index defined as the anomalous difference b/w the polar low and the subtropical high - dominant mode of winter climate variability in N Atlantic - large seesaw in atmospheric mass b/w the subtropical high and polar low
t/f NAO varies from year to year and does not remain in one phase for longer than a couple of years
false varies from year to year tends to remain in one phase for up to several years, which has consequences