CLIMATE

Weather vs Climate Weather: what is happening in the atmosphere at a particular place and time –Ex: Daily weather forecast for Minneapolis 24ºF, couple of flurries, clearing of clouds, cool Climate: average weather in an area, over a long period of time –Temperature, Humidity, Wind and Precipitation –Ex: warm summers, cold winters

What determines climate? 1. Latitude -amount of solar energy received

Equator: vertical rays Poles: oblique rays

2. Atmospheric Circulation Pattern -Cold air sinks and warms as it sinks -Warm air rises and cools as it rises -Warm air can hold more water vapor than cold air

Moisture is sucked from the surface at 30 degrees north and 30 degrees south because the air masses are increasing in temperature and are able to hold more water

3.Ocean Circulation Patterns Water holds a lot of heat “Conveyor belt”

4. Local geography –Mountains and mountain ranges

El Niño Named for “The Christ Child” because it comes around x-mas Disruption of the ocean-atmosphere system in the Tropical Pacific Abnormal warming of the surface waters –Consequence: global weather and climate change Strongest year:

From NOAA-November 5, 2009 El Nino is expected to continue strengthening and last through at least the Northern Hemisphere winter Expected El Nino impacts during November 2009-January 2010 include enhanced precipitation over the central tropical Pacific Ocean and a continuation of drier-than-average conditions over Indonesia. For the contiguous United States, potential impacts include above- average precipitation for Florida, central and eastern Texas, and California, with below-average precipitation for parts of the Pacific Northwest. Above-average temperatures and below-average snowfall is most likely for the Northern Rockies, Northern Plains, and Upper Midwest, while below-average temperatures are expected for the southeastern states.

An El Niño condition results when the trade winds pushing the water around get weaker. As a result, some of the warm water piled up in the west slumps back down to the east, and not as much cold water gets pulled up from below. Both these tend to make the water in the eastern Pacific warmer, which is one of the hallmarks of an El Niño.

But it doesn't stop there. The warmer ocean then affects the winds--it makes the winds weaker! So if the winds get weaker, then the ocean gets warmer, which makes the winds get weaker, which makes the ocean get warmer... this is called a positive feedback, and is what makes an El Niño grow.

La Niña Cold sea-surface temperatures in the eastern Pacific Conditions recur every few years and could persist for as long as two years Effects opposite of el Niño in most locations

Hurricanes Forms over really warm water (80° F +) Atmosphere cools off very quickly the higher you go Winds must be blowing in the same direction and at the same speed to force air up Typically form between 5 to 15 degrees latitude north and south of equator

Places on Earth where conditions are met for hurricane formation

08page01.cfm?chapter_no=visualization Animation of hurricane