4/3: CLIMATE & BIOMES

Weather

- atmospheric conditions over a short period time

• current conditions/individual events (today,tmrw,week)

• what you get

Climate

- avg annual patterns of temp & precipitation over long periods of time

• what you expect

Climatographs

- climate graph demonstrating avg temp & precipitation for a location over a course of a year

• x-axis: months (jan-dec)

• y-axis: bars; precipitation (rain/snow), line; temperature

• helps determine biome, temp range, warmest/coldest months, wettest/driest months

• large range = more seasonal climate, small range = stable climate

Davis Biome: Temperate Shrubland & Woodland

• hot, dry summers

• cool, moist winters

• dense vegetation

• vulnerable to summer fires

• found globally: south africa, australia, asia

Q: What determines Climate?

- incident solar radiation; amount of sunlight an area receives

• near the equator/low lat (0˚-30˚): direct sunlight; hotter climates, tropical

• temperate zones/mid lat (30˚-60˚): moderate climate, distinct seasons

• pole regions/high lat (60˚-90˚): low angle of incoming sunlight; colder climates

• Earth is tilted (~23.5˚); causing seasons

Q: What drives Latitudinal Patterns of Air Circulation?

- incident solar radiation (uneven heating from the Sun creates global wind patterns

1. Hadley Cell (0˚-30˚) equator

• air heats up & rises → cools & forms rain

• creating wet tropical rainforests at 0˚ & dry desserts around 30˚ n & s equator

2. Ferrel Cell (30˚-60˚) mid-latitudes

• air flows from 30˚→ 60˚

• middle circulation driven by other cells

• creating variable weather; storms & changing conditions

3. Polar Cell (60˚-90˚) high latitudes

• cold air sinks at poles

• creating cold, dry climates

Jet Streams (red lines) - fast moving winds found btwn cells

Q: What influences Precipitation?

- atmospheric circulation

- rising warm air → (evaporates & cools) forms clouds → heavy raina

• high precipitation near equator (0˚) due to strong sunlight (rainforests; amazon, congo)

• little to no precipitation around (30˚) due to sinking air warming (desserts; sahara, arabian, australian)

• moderate/dynamic precipitation (30˚-60˚) due to interactions of warm & cold air masses along the polar front (U.S., europe)

• low precipitation (60˚-90˚) due to cold air sinking & little moisture in air (north & south poles, alaska, antartica)

Q: What influences Vegetation?

- controls what plants can survive in a region through temp & precipitation

- influences type, density, & diversity of vegetation

• warm & wet → dense vegetation

• hot & dry → sparse vegetation

• moderate temp & rain → grasslands

• cold temp → limited vegetation

Biomes

- the world’s major communities, classified by predominant vegetation & characterized by adaptations of organisms to a particular climate.

• tundra

• boreal forest

• mountains

• temperate deciduous forest

• temperate evergreen forest

• temperate shrubland & woodland

• tropical seasonal forest & savannahs

• tropical rain forest

• temperate grassland

• dessert

Rain Shadow Effect

- moist air rises over a mountain, cools & precipitates on the windward side → then descends as warm and dry air on the leeward side, creating dry conditions

• double whammy - occurs when dry air picks up moisture once again & as it ascends it creates an opportunity for another rain shadow effect (wet, dry, wet, dry)

Seasonal Variation in Climate

- change in temp, sunlight, & precipitation over the year (seasons)

• caused by Earth’s tilt (23.5˚) & as it orbits the sun

• diff parts of Earth get diff angles of sunlight

Earth’s Radiation Budget

- the process of incoming & outgoing energy from the sun emitted or reflected by Earth into space

1. Incoming solar energy (100 units of sunlight)

- 31% reflected back to space

• 23% by clouds/atmosphere

• 8% by Earth’s surface

- 69% is absorbed

• 20% by atmosphere

• 49% by Earth’s surface

• absorbed energy warms planet

2. Re-emitted energy

• absorbed energy gets released as infrared (heat)

• surface emits 114 units of heat upward

3. Greenhouse effect

• greenhouse gases absorb & trap most of outgoing heat

• and send back down to Earth (back radiation) & out to space

4. Back radiation

• surface absorbs 95 units

• heating Earth by sunlight & heat trapped & re-radiated by atmosphere

5. Energy leaving Earth

• 69 units are lost to space

Polar Amplification

- Artic & Antarctic warm faster than global abg as planet heats up

• solar radiation reflects off sea ice, but as it mets deep ocean absorbs heat & increases temp