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* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Why Do We Have Weather? WHY DO WE HAVE THE WEATHER ? • Just think about it! • Why is there wind? Why does it blow from one direction one day and another the next? • Why is it rainy one day and dry the next? • How come it’s cold in the winter? • How can we have hail in the summer? • What causes snow and freezing rain? If we were to pick one term to help explain why we have weather, what do you think would be a good word? You might pick heat or sun….but another good choice would be _______ currents (hint: type of heat transfer: warm air rising,cools and falls back down) Convection is the transfer of ______, usually in _______ or liquids. After the atmosphere is warmed by radiation and conduction, heat is transferred throughout the atmosphere by convection. * warmed air has _____ space between molecules, it’s _____ dense & rises *Cooled air is more dense & tends to sink *In general, air near the equator ______ & air near the poles ______ The Coriolis effect-wind patterns because of earth’s rotation Take a look at this! Notice the band of clouds around the equator ? This is the ITCZ zone a.k.a ________________ _____________ __________ Why do you think there is this band of clouds near the equator? Did you figure it out? • Warm, moist air in the topics _____ • Cold air holds ____ moisture than warm air • As moist warm air _____, it condenses and forms ________! The Wind Highways • The Coriolis effect causes air & water to be deflected to the right or____________ north of the equator, and _____________south of the equator. • This creates global weather highways of wind. The Westerlies • Because of our latitude, most of our weather comes from the ____ • Looking at the weather map, what type of weather might we expect? ________ • What type of weather might we expect in a few days? _________ short review 1.Transfer of heat in liquids or gases is called _____. 2. _____ air is dense and tends to sink. 3. Band of clouds found around the equator______ 4. Cold air holds _____ moisture than warm air 5. The Coriolis effect causes the air and water to be deflected to the _____ of the equator Now What? • Ok, so we know that the weather moves around on these highways and that warm air rises and cold air sinks. • But why is it sunny one day, and rainy the next? Look at the weather map • Notice that there are ___’s(blue) and L’s (red) on the map • blue lines w/ spikes red lines w/ 1/2 circles High Pressure Areas • When cooler air sinks & is warmed, the air can hold ___ moisture. • This usually means _____ skies • Winds tend to move clockwise around high ______ ___ Low Pressure Areas • When warm air rises & is cooled, the air can not hold as much ______. • Often, these areas are associated w/ _________ (hint: rain snow sleet or hail) & stormy weather • Winds tend to move _______ _____around a low_______ _______. If you see a big blue ___on the weather map over your area, you can expect______ weather See a big red L in your area, there will probably be______ weather These highs and lows move more or less along the jet stream and brings changes in our weather Fronts & Air Masses • ____ _____is a large body of air whose __________ & ________ are fairly similar at a given altitude • _____ are boundaries separating different air masses • There are _____ different air masses that affect the United States The Air Masses • cP( continental polar) : ___, dry stable • cT( continental tropical) : hot, ____, stable air aloft, unstable at surface • mP( maritime polar) : cool, ____, unstable • mT( maritime tropical) : ____, ____, unstable Map shows air mass source regions and there paths Ok, now we see the difference in the air masses * look at the different fronts & their impact on weather • Can you see the four different types of fronts on the map? Warm Fronts * warm front is warm air displacing cool air diagram *Shallow leading edge warm air must “overrun” cold air *These are usually _____ moving Cold Fronts • _____ air advances into region of ____ air • Intensity of precipitation greater, but short lived • Clearing conditions after front passes • Usually approaches from W or NW Stationary Fronts • Surface positions of the front do not move • Often a region of clouds Occluded Fronts • Cold front overtakes warm front • Often found close to the low pressure center Ready for a little quiz? You’ll need a sheet of paper • Write your answers as we go • Here we go! 1. • Winds in a low pressure system move _____ around the low L 2. • Name type of front found close to point 3. • Which fronts would you expect to have greater precipitation, but be short lived as the front passes? 4. • Give the name of the air mass/front that would have the following characteristics: • cool, moist, unstable 5. That important weather word that refers to the transfer of heat (hint: rises and falls) 6. In general, air near the equator tend to_____. ( rise or fall ) 7. What causes air & water to be deflected to the right… north of the equator? 8. Which of the weather highways usually controls our weather 9. Warm air holds ( more or less ) moisture than cold air 10. • If there is a big H on the weather map where you live, would you expect fair or stormy weather? H 11. Band of clouds found around the equator______ 12. The Coriolis effect causes the air and water to be deflected to the _____ of the equator