What is Climate? The long term average of weather, usually 30 years+

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

Latitude The 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?

Global/Local Winds Winds flow from high to low pressure Winds influence climate by transfer of heat energy. Example: The ITCZ (intertropical convergence zone)

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

Continental Position Maritime 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-WHY Average Temperatures Summer/Winter Solstice Location CityJuly: high (°C/°F)January: low (°C/°F) West CoastSan Francisco, CA19/668/46 Central United StatesWichita, KS33/92-7/20 East CoastVirginia Beach, VA32/891/319 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?

Ocean Currents What do you notice about the color of water and exchange of heat?

How water circulates in the ocean

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.

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.

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 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

What does this look like to you?

El Nino

El Nino and La Nina Synopsis El Nino: 1.The trade winds reverse due to decresed pressure gradient and blow warm water towards South America 2.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?