Wind and weather NC Essential Standard 7.E.1.5: Explain the influence of convection, global winds and the jet stream on weather and climatic conditions.

= the condition of Earth’s atmosphere at a particular time and place. weather = the condition of Earth’s atmosphere at a particular time and place. WIND is an important part of weather.

wind = air that moves horizontally, or parallel to the ground. Air pressure can differ place to place at the same altitude. Uneven heating of the Earth’s surface causes such pressure differences and causes wind.

Wind moves from an area of HIGH PRESSURE to and area of LOW PRESSURE. 1) Sunlight heats an area of the ground  ground heats the air  warm air rises  area of low pressure forms.

Wind moves from an area of HIGH PRESSURE to and area of LOW PRESSURE. 2) Sunlight heats another area of the ground less strongly  Cooler, denser air sinks  Area of high pressure forms.

Wind moves from an area of HIGH PRESSURE to and area of LOW PRESSURE. 3) Air moves as wind across the surface, from higher toward lower pressure. Small pressure differences cause a little wind. LARGE pressure differences cause STRONG wind.

Varies; some die out quickly, & others are global. How far does it travel? Varies; some die out quickly, & others are global. Global winds travel 1000’s of kilometers in steady patterns and can last for weeks. Global winds are caused by uneven heating between the equator and the north and south poles.

Global winds Is the area of low pressure created in the equator or the poles? Is the area of high pressure created in the equator or the poles? Concentrated sunlight near the equator heats the surface to a high temperature…warm air rises and leaves an area of low pressure behind. Sunlight is more spread out at the poles (less heat energy) and so the air is cooler and denser. This air sinks and creates an area of high pressure.

CORIOLIS EFFECT = Describes how Earth’s rotation steers winds and surface ocean currents. -Causes freely moving objects to appear to move to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. -The objects are moving straight, but the Earth is rotating beneath them, so they seem to curve.

CORIOLIS EFFECT - Example If an airplane flies 500 miles due north, it will not arrive at the city that was due north of it when it began its journey. Over the time it takes the airplane to fly 500 miles, that city moved, along with the Earth it sits on. The airplane will therefore arrive at a city to the west of the original city (in the Northern Hemisphere), unless the pilot compensates for the change by also veering north.

Coriolis Effect Video 1

Coriolis EFFECT Activity 1) Get with your 3:00 appointment for this activity. 2) Predict in which direction a straight line will turn when drawn from top to bottom on a page spinning clockwise. 3) Predict in which direction a straight line will turn when drawn from top to bottom on a page spinning counter-clockwise. 4) Draw your predictions in the lab section of your notebook.

Coriolis EFFECT & wind Because the Coriolis effect causes global winds to curve, they cannot flow directly from the poles to the equator (high to low pressure). Instead, they travel along global wind belts that are separated by calm regions.

Calm region: doldrums Low-pressure zone near the equator Warm air rises to the top of troposphere, then spreads outward toward the poles. Rising, moist air produces clouds & heavy rain. Hottest months = heavy evaporation = tropical storms

Calm region: horse latitudes High-pressure zones located about 30° north and 30° south of the equator. Warm air traveling away from the equator cools and sinks. Typically clear and dry weather.