Lesson 3: Climate Flashcards
Global-scale drivers of mountain climates:
What is Weather?
- Weather is the hour to hour and day to day variability in atmospheric conditions.
- This includes temperature, precipitation, humidity, air pressure and wind at any specific location and these conditions can change rapidly.
Global-scale drivers of mountain climates:
What is Climate?
- Climate is the long-term average of weather and its extremes
- Climate is usually generally predictable, as weather is much more variable
Global-scale drivers of mountain climates:
At the Global Scale, what three primary forces regulate mountain climates?
- ) Latitude (distance from the equator)
- ) Elevation (height above sea level)
- ) Continentality (proximity of distance to large water bodies such as oceans)
Global-scale drivers of mountain climates:
Why are temperatures higher near the equator?
- Solar radiation
- The sun’s rays hit the Earth directly concentrating solar radiation. In contrast, at higher latitudes, the sun’s rays hit the earth at an angle (because of its sphere shape) causing the same solar radiation to be spread over a larger area
Global-scale drivers of mountain climates:
What is seasonality? Seasonality is greater or less at higher latitudes?
- How temperatures fluctuate during a year
- Greater
Video:
True or False: The Earth is closer to the Sun during the summer and further away from the sun during the winter…
- False - this is a common misconception. The northern hemisphere is actually closer to the sun during the winter, and further away in the summer.
Global-scale drivers of mountain climates:
What three factors cause seasonality to be greater in higher latitudes?
- ) The tilt of the earth on its axis
- ) The revolution of the earth around the sun
- ) The greater variation in solar radiation
Global-scale drivers of mountain climates:
At what angle, relative to the sun, is the earth tilted on its axis?
- 23.5 degrees
Video:
During summer in the Northern Hemisphere, solar radiation strikes the Earth most directly near the…?
- Tropic of Cancer around the latitude of 23.5 degrees North.
Video:
During summer in the Southern Hemisphere, solar radiation strikes the Earth most directly near the…?
- Tropic of Capricorn around the latitude of 23.5 degrees South.
Global-scale drivers of mountain climates:
What is the main point to remember about temperatures across the earth?
- There is a very predictable temperature imbalance over the surface of our planet created by uneven solar radiation across the latitudes.
- Whichever hemisphere, N or S, is tilted toward the Sun received solar radiation most directly, resulting in higher temperatures.
Global-scale drivers of mountain climates:
What is Atmospheric Circulation?
- Large scale movement of air on the surface of the earth, created by uneven solar radiation across latitudes, that controls global patterns of wind and precipitation
Video:
What is Air Temperature?
- Air temperature is just a measure of how hot or cold the air is
Global-scale drivers of mountain climates:
What is Air Density?
- The compactness of molecules in the air
- Hot air is less dense than cool air because the molecules are moving faster and filling up more space. This causes hot air to float upward, just like hot air balloons.
Global-scale drivers of mountain climates:
What is Atmospheric Pressure?
- The downward force of air in the atmosphere caused by gravity pulling molecules of air towards the air
- Lower air density leads to lower atmospheric pressure, because the more spread out air molecules are, the less force they exert
Global-scale drivers of mountain climates:
What are Pressure Gradients?
- Differences in atmospheric pressure between areas
- Air tends to move along pressure gradients from areas of high pressure to low pressure, forming wind and driving global circulation patterns
Global-scale drivers of mountain climates:
What is the Intertropical Conergence Zone?
- A zone near the equator where high temperatures create an area of low atmospheric pressure
Global-scale drivers of mountain climates:
Lower temps N and S of the equator create areas of high pressure. Following the high-to-low pressure gradient, air flows along the surface of the Earth from higher latitudes toward the equator. At the same time as air moves across the surface of the Earth toward the equator…?
At the same time as air moves across the surface of the Earth toward the equator, warm air that rises near the equator moves toward the poled, forming circulation cells.
Global-scale drivers of mountain climates:
What are Circulation Cells?
- Belts that encircle the earth in which prevailing winds occur
Global-scale drivers of mountain climates:
How many Circulation Cells are there?
- If the earth did not rotate, there would only be two, 1 in each hemisphere. However, since it does rotate, there are three in each hemisphere
Video:
In the Hadley Cell, warm air that rises at the equator and moves poleward sinks towards the ground around…
- 30 degrees latitude, creating high pressure zones. These high pressure zones around 30 degrees cause air to diverge and flow back towards the equator completing the Hadley Cell
Global-scale drivers of mountain climates:
What is the Coriolis Effect?
- The earth deflects winds so they do not flow directly north and south. This is because of the rotation of the earth
Video:
In what direction does the earth rotate?
East to West
Global-scale drivers of mountain climates:
In the northern hemisphere, winds appear to be deflected in which direction?
To the Right