CHAPTER 22.3 Weather and Climate

Objectives 1. Explain how fronts affect weather 2. Explain how climate is different than weather Key Terms: Air mass, front, climate, topography &bclid= &bctid= &bclid= &bctid=

Meteorologists track weather by collecting several types of data Air masses are large bodies of air throughout which temperature and humidity are similar Interactions between air masses have predictable effects on local weather Meteorologists can make predictions about weather based on the characteristics of the air masses

A front is a place where a cold air mass and a warm air mass come in contact Clouds, wind, and rain can sometimes occur at fronts On a weather map cold fronts are shown by blue lines with triangles while a warm front is a red line with semicircles

Front types include warm, cold, and stationary Warm fronts a mass of warm air moves toward and over a slower denser mass of cold air Nimbostratus clouds are common and can result in steady rain or snow for 1 or 2 days

At a cold front the forward edge of a cold air mass moves under a slower mass of warm air and pushes it up. Cumulonimbus clouds, high winds, thunderstorms and sometimes tornadoes can accompany this type of front

A stationary front occurs where two air masses meet but neither is displaced Weather near a stationary front are similar to that of a warm front

Lightning is a discharge of electrical energy Ice particles and water droplets move along the surface of the Earth and build up a charge The charge can be exchanged between clouds or between a cloud and an object on the Earths surface lightning/

Tornadoes are funnels of high speed wind Winds of a tornado can be as fast as 310 miles hr Typically tornadoes start out as water droplets known as a funnel cloud The air pressure inside the cloud is extremely low The high pressure on the ground rushes toward the center creating high winds These weather occurrences are extremely unpredictable

Hurricanes are large rotating tropical storm systems The name varies with where they form

These storms start out as tropical depressions, or areas of intense low pressure Hurricanes are powered by the release of water vapor into precipitation Although they are extremely slow moving they can cause a lot of damage Winds can reach 160 miles/hr in the eye wall. In they eye itself winds are calm Storm surge is the main cause of damage in low lying areas See demo…

Climate is what we expect, weather is what we get -Mark Twain Climate is the average weather of a region and is measured over many years Temperatures tend to be higher closer to the equator because of more concentrated solar energy The equator is almost always perpendicular to the sun

Earths tilt and rotation account for our seasons The tilt of 23.5 degrees past 90 degrees accounts for our seasons in the fact that one side of the Earth can be tilted toward the sun at any given time See page 794 for a diagram

The rise and fall of Earths surface is known as topography (ever hear of a topographic map?) Remember how a rain shadow forms? Review this! See a diagram on page 795 What other land features can effect climate?

List some ways that global climate can change over a long period of time.