what is climate? the long term average of weather, usually 30 years+
TRANSCRIPT
What is Climate?The long term average of weather, usually 30
years+
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What is Climate Dependent on?
1. Latitude
2. Global/local winds
3. Continental Position (closeness to ocean or large body of water)
4. Ocean Currents
5. Altitude/proximity to mountains
What influences these factors?
1. Movement of heat via currents within the atmosphere and ocean
2. Type and amount of vegetation-why?
3. Composition of atmosphere
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LatitudeThe amount of solar energy a location
receives is most important factor in its temperature.
The lower the latitude the greater amount of sunlight and the longer the days.
WHY?
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Global/Local WindsWinds flow from high to low pressureWinds influence climate by transfer of heat
energy. Example:
The ITCZ (intertropical convergence zone)
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The ITCZ shifts with seasons, north about 5° during northern hemisphere summer (because land heats up faster that water)
As this belt of wind is comprised of warm humid air, this will dictate rainy seasons along its current latitude
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Continental PositionMaritime Climate:
Summers are not too hot, winters not too cold (remember these are relative descriptors)
Wind frequently comes from the sea-WHY?
Continental Climate:
Greater range of temperatures-WHYAverage Temperatures Summer/Winter SolsticeLocation City July: high (°C/°F) January: low (°C/°F)West Coast San Francisco, CA 19/66 8/46Central United States Wichita, KS 33/92 -7/20East Coast Virginia Beach, VA 32/89 1/319
Ex:
Note: These three locations are all at the SAME latitude (37°N)
Ocean Currents
Temperature of water offshore will influence temperature of a coastal location, particularly if winds come off the sea-WHY?
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Ocean Currents
What do you notice about the color of water and exchange of heat?QuickTime™ and a
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How water circulates in the ocean
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Describe this in your notes in your own words. Differentiate the red and blue in terms of density. Make note of where you see the blue and red lines. Is there any correlation? Explain.
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Mountain Ranges
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Mountain Ranges
What you saw on the previous slide was the rainshadow effect.
As moist air rises over a mountain, it cools and drops precipitation. The drier air then descends down the other side of the range.
This process creates a high pressure region on the back side of the mountain where evaporation exceeds precipitation.
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Practice Questions
1. What is the ITCZ? How is it influenced by seasons and how does this affect weather along it’s current latitude?
2. Why would the ocean off California cool off the coastline while the water off southeastern US warm the region?
3. How would the climate at 45°N be similar or different that climate at 45 °S?
How does Climate change in the short term?
El Nino and La Nina-change climate around the world every 2-7 years.
Top is normal conditions.
Bottom is El Nino
Normal Conditions
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Cold nutrient rich water upwells to warmer water near the surface along coast of South America and this is transported across the Pacific by wind along the equator
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What does this look like to you?
El Nino
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El Nino and La Nina SynopsisEl Nino: 1. The trade winds reverse due to decresed pressure gradient and blow
warm water towards South America2. This results in lots of rain in Western South America, more rain in
Southern US and warmer temperatures in Western US
La Nina: 1. The trade winds blow normally (E to W) but the water is much colder than
usual.2. Colder, rainier/snowier than normal in western and middle US
Practice questions
1. If California has warmer usual water off its coastline due to El Nino, what will happen to the climate for the next 2-3 years? Will this change the weather on the continental side of the Sierra Nevada mountains? Explain reasoning.
2. What is El Nino and how does it happen?
3. How does the transfer of heat relate to our discussion of El Nino and La Nina?