1 geology 1001/1101 sec 003 chris paola class 12: climate and glaciation
TRANSCRIPT
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Geology 1001/1101
Sec 003 Chris PaolaClass 12: climate and glaciation
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Chapter 10
THE CLIMATE SYSTEM
AND GLACIATION
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Key ideas about climate & glaciation
• Much of Minnesota’s landscape has been sculpted by glaciers
• Glacial cycles are controlled by variation in Earth’s orbit on time scales of 10,000 – 100,000 yr
• Climate weather; climate is long-term average of weather
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Climate: planetary controls
• Distance from Sun
• Albedo (reflectivity or “whiteness”)
• Atmosphere (greenhouse effect)
• Orbital properties
• Plate configuration (mainly due to effect on ocean circulation)
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Climate: geographic controls
• Distance from equator
• Average air flow & pressure
• Distance to the ocean
• Prevailing wind relative to mountains & ocean
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Hot
Cold
NOT distance to Sun!
3,900 miles
92,900,000 miles
7all sunlight that hits Earth’s surface
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10% of sunlight spread across 6.5% of sunlit surface
at equator, Earth’s surface is almost perpendicular to sunlight, so energy is concentrated in small area
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10% of sunlight spread across 6.5% of sunlit surface
~ 150% of average intensity
at equator, Earth’s surface is almost perpendicular to sunlight, so energy is concentrated in small area
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10% of sunlight spread across 6.5% of sunlit surface
10% of sunlight spread across 20.5% of sunlit surface
~ 150% of average intensity
at poles, Earth’s surface slopes away from sunlight, so energy is spread across a greater area
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10% of sunlight spread across 6.5% of sunlit surface
10% of sunlight spread across 20.5% of sunlit surface
~ 150% of average intensity
< 50% of average intensity
at poles, Earth’s surface slopes away from sunlight, so energy is spread across a greater area
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Hot
Cold
due to the angle of the Earth’s surface
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Global air flow determines large-scale rainfall patterns
Mars: one cell perhemisphere
14Earth: 3 cells perhemisphere
wet
dry
dry
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Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Energy and power
• Energy (work) – Joules– BTUs: 1 BTU = 1055 J– Kilowatt-hour: 1 KWH = 3600000 J– Calorie (food): 1 Cal = 4187 J
• Power: energy per time (energy rate)– 1 Joule/sec = 1 Watt– 1 HP = 746 Watt
• US energy consumption (power), per capita: 11.4 kW (11,400 Watt)
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
99%
of
air
mas
s
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Importance of the ocean in climate
• Heat storage (heat capacity of water >> that of air)
• Heat and moisture transport
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Ocean currents
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Importance of the ocean in climate
• Heat storage (heat capacity of water >> that of air)
• Heat and moisture transport
now onto the cryosphere…
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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A side note: Ice and sea level
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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El NiñoWarm, rising air here lo pressure helps maintain the wind pattern
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El Niño movie
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Part II: glaciation
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Movies
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Minnesota in the ice age
Thanks to MN State U
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota in the ice age
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Minnesota glacial features
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Minnesota glacial features
Satellite image
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Minnesota glacial features
Thanks to geologyclass.org
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Minnesota glacial features
Moraine map, S Minnesota
Big Stone Moraine, Traverse Cty
End moraine, Freeborn Cty
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Minnesota glacial features
Superior Lobe till, central MN, thanks to Karen Kleinspehn
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Minnesota glacial features
Drumlin
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Minnesota* glacial features
Drumlins
*OK, Saskatchewan
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Minnesota* glacial features
Drumlin field near Green Bay
*OK, Wisconsin
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Minnesota glacial features
Drumlin?
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Minnesota* glacial features
Esker, Oakwood Lake
*OK, S. Dakota
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Minnesota glacial features
Esker
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Minnesota glacial features
Esker, Finlayson MN
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Minnesota* glacial features
Esker
*OK, Wisconsin
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Speaking of glaciers and volcanoes…
Word of the day: jokulhlaup
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Jokulhlaup
Former bridge
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Our own version…
Montana/Idaho glacial lakes
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Channeled scablands
Eastern WA
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Evidence for a similar flood in the English channel
(S. Gupta, Imperial College London)
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Longer history and causes of glaciation
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
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favors glaciation
100 kyr
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Lower solar intensity in NH
41 kyr
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NH summer when Earth farthest from Sun
NH winter when Earth farthest from Sun: favors glaciation
23 kyr
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company