The diagram shows weather instruments A and B

The diagram shows weather instruments A and B. Which table correctly indicates the name of the weather instrument and the weather variable that it measures?

Weather?

LOW pressure air • Less dense • Weighs less • Tends to rise • Warm 1012 1008 1004 L • Wet • Lousy weather (rainy, snowy, etc…)

HIGH pressure air • More dense • Weighs more • Tends to sink • Cool 1004 1008 1012 H • Dry • Nice weather (sunny, blue sky, etc…)

In late October cool weather is relatively H pressure. Watch the L pressure storm develop: LOW PRESSURE means. . . Warmer More Humid

Is HIGH or LOW pressure normal? At the Equator? Low On a sunny day? High On a winter day? High On a rainy day? Low At the North Pole? High

Two reasons why air becomes HIGH or LOW pressure : 1. Unequal heating of Earth’s surface. 2. Change in humidity. --we will discuss water vapor later--

Why would the sun make the ground hot in one place and not as hot in another place? Color Texture Specific Heat…

At pressure centers… • Different surfaces absorb different amounts of energy (color, texture, specific heat, etc…)

At pressure centers… • Different surfaces absorb different amounts of energy (color, texture, specific heat, etc…) • Low density air is created above warm surface.

At pressure centers… • Different surfaces absorb different amounts of energy (color, texture, specific heat, etc…) • Low density air is created above warmer surface. • Density change causes air to move… t e g s g n i h t n The ! g n i t s intere

Which transfer of energy occurs mainly through the process of convection? (1) electromagnetic energy transferred from the Sun to the Moon (2) solar energy transferred through space to Earth’s surface (3) heated air in the lower atmosphere transferred upward by density differences (4) heat from radioactive decay transferred by molecular collisions to surrounding mantle rock

Air pressure decreases as air heats above a warm Earth surface. Warm, LOW Density Air Low density air Cold, HIGH Density Air

As HIGH pressure air sinks, it hits surface and diverges (spreads out). As LOW pressure air rises, more air converges (comes together) to fill empty space.

It’s a CONVECTION CURRENT

H L Air moving horizontally from higher to lower pressure is WIND.

H L Air moving horizontally from higher to lower pressure is WIND.

Air moves like water. . . Small gradient = Slow Big gradient = Fast The larger the AIR PRESSURE GRADIENT, the faster the wind moves from HIGH to LOW pressure!

The larger the pressure gradient, the faster the wind!

Which location most likely recorded the highest wind speed? (1)A (3)C (2)B (4)D

The map at left shows pressure measured in mb. The distance between the points is 500 Km. CALCULATE the pressure gradient. Gradient = Change in field value/ distance Gradient = 1004 mb – 976 mb/ 500 Km Gradient = 0. 056 / = 28 mb 500 Km mb/ Km