what is climate?

climate is a long term environmental condition or weather pattern. 

what is weather?

it is the environmental condition prevailing today and in the short term. 

how is the climatic pattern determined?

determined by distribution of heat (measured by temperature) and moisture on a yearly basis at a particular location on the globe 

what are temperature and moisture patterns associated with?

latitude

by what are temperature and moisture patterns altered?

1. prevailing winds
2. mountain ranges
3. presence or absence of local bodies of water (oceans & lakes)

• Differential heat orginating as electromagnetic radiation from the sun (a function of latitude)
• mositure availability (partially a function of latitude)
• prevailing winds (modified by the Coriolis force); and
• Local features of landscape (bodies of water, mountains, etc)

every point on the globe receives the same number of hours of electromagnetic radiation (ER) per year. 

but not the same amount of energy. 

In addition, variation in day length is:

• minimized tropical latitudes
• maximized in polar latitudes

the sun is directly overhead only in tropical latitudes

those latitudes where the sun is directly overhead at noon at least once a year.

occurs within 23.5 degrees N (tropic of cancer) and 23.5 degrees S (Tropic of Capricorn)

• The sun is directly overhead at the Tropic of Capricorn.
• this date is also the shortest day on the year in the Northern Hemisphere and the longest day of the year in the Southern Hemisphere. 

• temperature in the "temperate" and polar zones
• rainfall in the tropics.
• that is, wet vs. dry seasons in the tropics (Terms like "summer" for the wet season are problematic)

1. warm air has a much greater capacity to mold moisture as compared to cool air.
2. warm air is less dense than cool air and therefore rises.

1. proximity to the ocean or other large bodies of water
2. the prevailing winds
3. mountain ranges

1). Determined by convection cells 

2). the Coriolis force

3). Convection Cells plus Coriolis Force combine to produce the prevailing winds.

4). the prevailing winds, in turn, determine ocean currents, which affect local terrestrial climates

1. Air masses in the Northern Hemisphere are deflected to the right as they move along the surface of the Earth.
2. Air masses in the Southern Hemisphere are deflected to the left. 

1. At or near 30 degrees latitude
2. on the leeward side (as opposed to windward side) of the prevailing winds. 

• ocean currents are the movement of surface waters in the oceans
• they are the result of being pushed by the prevailing winds. 
• ocean currents follow the prevailing winds, but are also shaped by the positions of the continents.
• the Gulf Stream, for example, is produced by the presence of the Central American land bridge, and influences climates as far away as the British Isles

• moister / less

1. Light. In a mature forest less than 1% of incident light may reach the forest floor. 
2. relative humidity is often 80-100% near the ground but only 60% in the canopy.
3. Temperature variations near the ground: 1.4 - 3.2oC but 7.2 - 12.4o C at 18 meters from the ground.
4. wind speed is much greater at higher portions of forest canopy, much less near ground. 

• location
• aspect

• top of hill, warmer, drier, sunnier
• bottom of hill, cooler, mositer, fewer hours of direct sunlight. 

1. light
2. temperature, and
3. moisture availability.