Lesson 3 Flashcards
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.
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
At the Global Scale, what three primary forces that regulate mountain climates are:
- ) Latitude (distance from the equator)
- ) Elevation (height above sea level)
- ) Continentality (proximity of distance to large water bodies such as oceans)
Why are temperatures higher near the equator?
- 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
What is seasonality? Seasonality is greater or less at higher latitudes?
- How temperatures fluctuate during a year
- Greater
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.
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
At what angle, relative to the sun, is the earth tilted on its axis?
- 23.5 degrees
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.
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.
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.
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
What is Air Temperature?
- Air temperature is just a measure of how hot or cold the air is
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.
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
What is the Intertropical Conergence Zone?
- A zone near the equator where high temperatures create an area of low atmospheric pressure
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
Following the high to low pressure gradient, air flows along the surface of the earth from…
At the same time as this flow, what happens?
- Higher latitudes towards the equator
- At the same time as air moves across the surface of the earth towards the equator, warm air that rises near the equator moves towards the poles, forming circulation cells
What are Circulation Cells?
- Belts that encircle the earth in which prevailing winds occur
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
In the Hadley Cell, warm air that rises at the quatory 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
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
In what direction does the earth rotate?
East to west
In the northern hemisphere, winds appear to be deflected in which direction?
To the Right
In the southern hemisphere, winds appear to be deflected in which direction?
To the Left