Ecology-CH2/3 Climate and Terrestrial Biomes

LO: How do weather and climate differ?

• Weather=the current short-term conditions in a specific place, at a specific time.

  • Influenced by climate

  • Combo of temp, humidity, precip, wind cloudiness, any other atmospheric conditions

• Climate= long term average of weather

  • variation measured over decades

  • includes daily, seasonal, yearly, and decadal cycles

  • local, regional, global

• Long term climate change results from

  • changes in intensity and distrib. of solar radiation

  • Changes in overall energy balance of the planet

  • Currently due to increase [co2] and other greenhouse gases due to human activity

When solar energy hits Earth…

• It can be absorbed/reflected

  • Absorbed by earth/atmosphere

  • Reflected by clouds/the surface

• Lost due to evaporation (latent heat flux) or convection and conduction in the atmosphere (sensible heat)

• Energy absorbed by the earth is emitted as IR radiation

  • some heads out to space

  • some is reflected back by atmospheric gg gases like water vapor, co2, CH4, N20

How does solar radiation vary geographically?

• Average annual surface net radiation decreases as you move away from equator

Equator

• Suns rays strike earth perpindicularly

• max energy per unit area

Poles

• Rays are spread over a larger area

• take a longer path through the atmosphere

• LESS energy per unit area

How does solar radiation varying geographically affect climate?

Outcome 1

• Latitudinal variation in temp

  • driving force for most climate dynamics

Outcome 2

• Variation in precipitation

The geographic variation in solar radiation affects more than just temp but also..

• Cloud formation and rainfall

1. Solar radiation heats earths surface

2. Causes air circulation

   a) earth’s surface heats air above it

   b) warm air less dense, rises

   c)as it gets higher, atmospheric pressure decreases, rising air expands and cools

Hadley cells: atmospheric circulation cells

Tropical regions recieve the most solar radiation- affects precipitation

1. Uplift of air results in a low atmospheric pressure zone

2. when warm air masses reach the upper atmosphere, cools, and drop rain

3. Dry air flows towards poles

4. At 30 degrees N and S, air descends, forms a high-pressure zone

   • Creates major deserts at these latitudes