Weather and Climate s1

Weather and Climate

1. Weather- is the condition of the bottom layer of the earth’s atmosphere in one place over a short period of time

A description of weather usually mentions temperature, moisture or precipitation.

Atmosphere- a multilayered band of gases, water vapor, and dust above the earth.

Green house effect- is the trapping of the suns solar radiation inside the earth’s atmosphere.

2. Climate- is the term for the weather patterns that an area typically experiences over a long period of time.

Weather and climate are related but not synonymous.

Rotation and Revolution Rotation- is the earths movement on it’s axis -the earth is tilted at 23 ½ on it’s axis

Revolution- is one complete orbit around the sun. - one revolution occurs every 365 ¼ days - to account for the ¼ ;every four years we make the year 366 days (Leap Year), we add a day in February Seasons The earth’s tilt means that the sunlight strikes different parts of the planet more directly. This causes the season to change.

Solstices- when the sun appears directly overhead at the Tropics of Capricorn and Cancer -summer (June 21) when the Northern Hemisphere is tilted closer to the sun -winter (December 21) Southern Hemisphere is tiled closer to the sun

Equinoxes- the sun, at noon, appears directly overhead at the Equator. - spring (March 21) - fall (September 23) - on these dates the lengths of day and night is nearly equal everywhere on earth

Latitude and Climate

Geographers use latitude, or distance from the Equator to divide the world into zones.

 Tropical zones (low latitudes)-are measured from 23 ½ degrees north and south latitude  Temperate zones (middle latitudes)-are measured from 23 ½ - 66 ½ degrees north and south latitude  Polar zones (high latitudes)-are measured from 66 ½ degrees North and south latitude to the poles. Distributing the Sun’s Heat

Convection- the transfer of heat from one place to another - warm gases and liquids rise - cooler gases and liquids sink

Distributed 2 different ways- (wind and water) - warm from the equator to the poles - cold from the poles to the equator

1. Wind -Rising warm air creates areas of low pressure -Falling cool air causes areas of high pressure

Coriolis effect- is the deflection of the winds from the equator and the poles.

Doldrums- the area near the equator which has light winds Horse latitudes- 30 North and South latitude, calm

Trade winds- blow toward the equator, between the doldrums and horse latitudes

2. Water (Currents) -currents carry warm water from the equator to the poles -wind and Coriolis effect influence the circular patterns of currents in the oceans Precipitation

Humidity- is the amount of water vapor contained in the Atmosphere

Precipitation- is all forms of water that fall from the atmosphere onto the earth’s surface.

-forms as air temperature changes -warm air absorbs more moisture than cool air -when the air cools the vapor condenses into liquid -tiny droplets of water gather together to form clouds -precipitation occurs when more water collects in the clouds than they can hold

1. Convectional Precipitation -occurs when humid, hot air rises and cools, losing water. Most common near the Equator

2. Orographic Precipitation -when warm moist air is forced upward over high landforms, it cools, forms cloud and loses water (rain or snow)

3. Frontal Precipitation -two fronts (air masses) meet -warm air is forced up by heavier cool air, the warm air cools and frontal precipitation forms