Transcript Ground Rules, exams, etc. (no “make up” exams) Text: read

Meridional Circulation Patterns
Atmospheric Cells, Jet Streams,
Adiabatic Cooling and Warming,
Horse Latitudes
Coriolis Force
Ocean currents move heat to higher latitudes on east coasts,
and cold polar water towards the equator on west coasts.
Latitudinal Belts of Average Annual Precipitation
Geographic Distribution of Average Annual Precipitation
Rainshadow Effect
Earth’s Annual Elliptical Orbit around the Sun
Angle of Inclination of Axis is currently about 23.5°
(wobbles between 22° and 24.5° every 41,000 years)
Milankovitch Cycles
Perihelion — at present, earth is closest to sun during winter in the
northern hemisphere (11,000 years ago it was closest to the sun during
summer in the northern hemisphere) (22,000 year cycle). Orbit itself
shifts <——>
Angle of inclination varies cyclically
from 22° to 24.5° with a periodicity of
about 41,000 years (currently about 23.5°)
Earth’s orbit changes from relatively circular
to more elliptical and back again over a 95,000 year cycle.
Daylength (Photoperiod) changes seasonally, but differently
at different latitudes — no change in daylength at equator
Annual
March of
Average
Monthly
Precipitation
(seasonal
Patterns of
Precipitation)
Climographs
Plot average
Monthly
Temperature
Against
Average
Monthly
Precipitation
Two plots of temperature against moisture. (a) Climographs for an area in Montana
where the Hungarian partridge was introduced successfully and a Missouri locality
where its introduction failed, compared to the average climatic conditions of its
European geographic range. Apparently Missouri summers are too hot and/or too wet
for these birds. (b) Plots of temperature versus relative humidity in 1927 and 1932 in
Israel superimposed on optimal (inner rectangle) and favorable (outer rectangle)
conditions for the Mediterranean fruit fly.
Geographic Distribution of Climates
Trifluoromethyl Sulfur Pentafluoride: SF5 CF3
During the past few decades, a new greenhouse gas
molecule has begun to appear in Earth’s atmosphere.
Air trapped in glaciers before 1960 does not contain
SF5 CF3. It must be man-made, but we don’t know where
it is coming from.
Each molecule traps as much heat as 18,000 CO2
molecules. SF5 CF3 is increasing at rate of 6% per year.
Moreover, this molecule is extremely stable with a half
life of 1,000 years.
The Interface between Climate and Vegetation
Plant Life Forms and Biomes
Tundra
Taiga (northern coniferous forest, spruce forest)
Temperate Deciduous Rain forest
Tropical Rain forest
Tropical Deciduous forest
Tropical Scrub forest
Temperate grassland and savanna
Chaparral
Desert (warm, cold)
Mountains (complex zonation)
Distribution of Major Vegetation Types
Geographic Distribution of Climates
Idealized Thermal Profile
Daily March of Temperature
Microhabitats
Leaves droop(wilt) which reduces solar heat load
Leaves in shade present their full surface to collect
as much incoming solar radiation as possible.
Similarly, desert lizards position themselves
perpendicular to the sun’s rays in early morning,
when environmental temperatures are low, but during the
high temperatures of midday, these same lizards reduce
their heat load by climbing up off the ground into cooler air,
facing directly into the sun, thereby reducing heat gained.
Temperature profiles in a growing cornfield at midday.
Microhabitat Selection
Plants buffer temperatures and humidites for
animals (also wind). An aphid lives in a 2mm
thick microhabitat with 100% humidity.
Soils act similarly: temperature and moisture
content are more stable deeper down.
Wind operates to increase thermal exchange
(“wind chill” effect) and also has a desiccating
effect.
Wind Velocities
Primary Productivity versus Average Annual Precipitation
Net Primary Productivity and World Net Primary Production
for Major Ecosystems
__________________________________________________________________
Net Primary Productivity
per Unit Area (dry g/m2/yr)
World Net
–––––––––––––––––––––––––
Primary
Area
Normal Production
6
2
(10 km )
Range Mean (109 dry tons/yr)
__________________________________________________________________
Lake and stream
2
100–1500
500
1.0
Swamp and marsh
2
800–4000 2000
4.0
Tropical forest
20
1000–5000 2000
40.0
Temperate forest
18
600–2500 1300
23.4
Boreal forest
12
400–2000
800
9.6
Woodland and shrubland
7
200–1200
600
4.2
Savanna
15
200–2000
700
10.5
Temperate grassland
9
150–1500
500
4.5
Tundra and alpine
8
10–400
140
1.1
Desert scrub
18
10–250
70
1.3
Extreme desert, rock, ice
24
0–10
3
0.07
Agricultural land
14
100–4000
650
9.1
Total land
149
730
109.0
Open ocean
332
2–400
125
41.5
Continental shelf
27
200–600
350
9.5
Attached algae, estuaries
2
500–4000 2000
4.0
Total ocean
361
155
55.0
Total for earth
510
320
164.0
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