Meteorology Weather State of variables temperature wind air

Meteorology

Weather = State of variables (temperature, wind, air pressure) of the atmosphere at a location for a short period of time

Wind sock b. ___________ Wind direction ____________ barometer a. ____________ Air pressure ______________ anemometer c. ____________ Wind speed _____________

Weather vane e. ____________ Wind direction _____________ Rain gauge d. __________ rainfall _________ thermometer f. ___________ temperature ____________

Sling psychrometer h. ____________________________________ Dewpoint & Relative humidity Weather balloon g. ____________ Weather variables ______________ Temperature, air pressure, cloud height, precipitation, humidity

Causes of Weather: Unequal heating of Earth’s surface Factors that Effect the Amount/Rate of Heating Angle 1. _______________ and Duration (amount) ________________ of insolation

Water 2. _____ Land vs. _______ • Specific heat: Land = low heats & cools fast Water= high heats and cools slow

3. _______ Color ______ vs. _______ Dark Light Dark absorbs. Light reflects Texture 4. _______ Rough _______ vs. ______ Smooth Rough absorbs. Smooth reflects

Composition of the Atmosphere l Atmosphere: Layers of gases surrounding Earth l Composition 78% l Nitrogen ____ 21% l Oxygen ____ l Argon- . 84% l Carbon Dioxide-. 03% l Other gases-. 01% l Also: Water vapor l __________ Dust particles l __________ p. 1 E. S. R. T

Early atmosphere § No Oxygen, only – Carbon dioxide, sulfur, water vapor and nitrogen from volcanoes – Sunlight split water vapor to form Oxygen – Oxygen then ↑ due to life forms Forming the atmosphere

Selected Properties of Earth’s Atmosphere (p. 14)

Structure of the atmosphere 1. Troposphere- lowest layer, all weather - Starts at Earth’s surface Temperature ↓ with altitude Water vapor↓ with altitude Pressure ↓ with altitude (air gets thinner)

Selected Properties of Earth’s Atmosphere (p. 14)

u Stratosphere- constant clean weather. Dry & strong winds – Ozone found here – Temperature ↑ with altitude caused by O 3 – Ozone absorbs harmful UV rays and releases it, in the form of heat – Jets fly in this layer

Selected Properties of Earth’s Atmosphere (p. 14)

u Mesosphere- temperature drops fast – Very little gases – Coldest layer – Meteors are burned up here

u Thermosphere- temperature rises again – Extremely thin, but intense insolation – Divided into two layers u. Exosphere- satellites u. Ionosphere- home to auroras

Selected Properties of Earth’s Atmosphere (p. 14)

39 865 -10 38

1018. 0 1018. 4 982. 2 975. 6 984. 8 1000. 1 1018. 2 989. 1 988. 8 1011. 1 206 281 080 168 888 800 987 768 000 165

053 Air pressure (mb) (1005. 3) Station model Below 500 add 10 Above 500 add a 9 542 954. 2 and add a decimal before last number 1010. 1

l l l l l Temperature: 36°F Precipitation. 45 in Dewpoint: 37°F overcast Winds NW Wind speed 25 knots Air pressure 987. 4 mb Pressure has been decreasing Visibility 1 mile Present weather : drizzle

A. 74 122 72 -31. 50 2 Temp Dewpoint Visibility Pressure Present weather Pressure trend Precipitation Wind direction Wind speed Cloud cover

Mapping a Temperature Field Isotherms- Lines connecting points of equal temperature Draw isotherms using an interval of 10°F, starting with 30°F

d e c b

l Isobars- Lines that connect points of equal air pressure

► Air Pressure 1. What is the cause of air pressure- The force of gravity pushing down on the air ____________________. B. Instrument used to measure air pressure Barometer - Units for measuring air pressure Millibars/ Inches of Mercury

Millibars (mb) Inches of Mercury 1030. 0 1014. 0 996. 0 30. 41 29. 95 29. 41 1000. 0 29. 53 969. 0 28. 62

1. Wind is caused by - differences in air pressure 2. What instrument measures wind speedanemometer ____________ 3. Winds are always named for the direction of origin (where they come from) ______________ breeze b. Breeze blowing onshore from sea= Sea ______ H pressure to areas 4. Winds blow from areas of _______ of ______ L pressure

Rotation 5. Due to Earth’s _________ we experience the _______ effect. Coriolis a. Northern Hemisphere winds are deflected to the _____ RIGHT b. Southern Hemisphere winds are deflected to the ______ LEFT 6. A measurement of the change in air pressure over a distance is called a _________ pressure gradient faster 7. The closer the isobars the ______ the winds

Low Pressure Warm Less dense Rising Clouds Counterclockwise Toward/ Into Convergent Cyclone High Pressure Cold More dense sinking No clouds clockwise Away/ out of divergent anticyclone

n Weather follows a pattern from West East (NE) in the U. S.

l l Zones of Convergence. Winds Divergent 0º, 60º N & S (wet) 30º N&S, 90º N&S (dry)

Cool down slower Warm up slower Remember Specific Heat !!!! Water has a higher specific heat (_______________) Land lower specific heat Warm up faster and cool down faster

Sea Breeze Low High Warm Cold

Land Breeze High Low Cold Warm

Moisture in the Atmosphere 1. The primary source of moisture for the atmosphere is the ______. oceans Other sources include: __________________ Lakes, rivers, soil, plants - 2. Moisture in the atmosphere exists in all three states/phases. (____________) Solid, liquid and gas Humidity Amount of water vapor in the air 3. _____-

The temperature which air must Dewpointcool in order to reach saturation Relative Humidity- The amount of water vapor in the air to the amount it can actually hold (%)

5. Saturation- When air holds as much water as it can Saturation occurs when 6. _________________ Air temperature = Dewpoint Temp ______________

Factors Affecting the Rate of Evaporation Temperature A. _______- As temperature increases the rate of evaporation increases As wind increases the rate of Wind B. ______evaporation increases As humidity increases the rate Humidity C. _______of evaporation decreases As surface area increases Surface Area D. _______- rate of evaporation increases

Rate of Evaporation Temperature Surface Area Wind Humidity Rate of Evaporation

l l When can you feel humidity more? increases b. As air temperature _______, the amount of water vapor the air can hold ______. increases

As dew point and air temperature become closer: water vapor condenses into droplets of liquid water Clouds will form Higher probability of rain

Warm air rises (less dense) ¡ Expands (less pressure pushing on it) ¡ Cools to the dewpoint ¡ Condenses ¡

§ Clouds Cloud Formations – Are tiny droplets of liquid water/ice crystals suspended in air § Conditions Needed For Cloud Formation Moisture in the air – __________________________ Cooling temperature Dust particles – _____________ Condensation nuclei (salt, pollution, dust) § ______________ § Dust Particles- “Condensation Nuclei” Aerosols in the atmosphere which provide a surface for water molecules to condense on

Find dewpoint temperature : n n 1) Dry bulb 11°C, Wet bulb 6°C 2) Dry bulb -4°C, relative humidity 32% Find Relative humidity n 3) Dry bulb 27°C, dewpoint 18°C Find wet bulb n 4) Dry bulb 16°C, dewpoint 9°C n 5) Dry bulb 30°C, relative humidity 72%

Air Masses and Fronts • A. Large body of air in the troposphere with moisture and similar characteristics of ___________ temperature 1. Air mass get these properties based on their ________ Source ________ Region

• Sits over water= wet, sits over land= dry • Sits over a region that is warm= Tropical Cold = Polar

Symbol Name of air mass Characteristics Dry & Cold c. P Continental Polar m. T Maritime Tropical Moist & Warm c. T Continental Tropical Dry & Warm Maritime Polar Moist & Cold m. P c. A Continental Arctic Very cold, very dry

l Boundary between 2 air masses Fronts _______________ l Weather is ______ near a front Unstable l Types of Fronts cold warm l ________ stationary l _______________ occluded l ________ Pg. 13 E. S. R. T.

u Cold Front- occurs when heavy cold air displaces Cold front anim lighter warm air, pushing it upward. Precipitation occurs ON a cold front

Warm Front- occurs when warm air replaces cold air by sliding over it. Precipitation occurs AHEAD of a warm front.

Lake Effect Snow: Cold dry wind blows across a warm lake and picks up moisture.

Katrina formation Hurricanes § § low Areas of intense _______ pressure Occur late summer or early fall Tropical (warm) _____ waters Form over ________ Gain energy from the condensation of millions of gallons of water vapor from solar evaporation land § Lose energy when they go over ______ Cold water or ________ Storm surge High winds § Produce _______, and ______

300 miles in diameter • Size (avg. ) ______________ usually a week/more • Length ___________ • How to prepare – LEAVE the area, use emergency routes – Get supplies (food, water, batteries) – Board up windows & doors (Wind speeds)

Before and After

Tornados n n n Occur spring and early summer A very cold, dry air mass meets Forms when a very warm, wet air mass Dangers High winds (flying debris) , low pressure (vacuum) 100 ft in diameter Size __________ only a few minutes, some over an hour Length ________________

n How to prepare n ___________________ Lowest level, strongest room & cover your head ________ n ___________________ Food, water, flashlights & batteries Open windows to let some pressure n ___________________ out or windows will break _______________ DO NOT RUN!!! Joplin Storms form when 2 different air masses meet

Flooding n n n 1. Higher ground 2. Life boat Supplies

n n n Lightning 1. Inside 2. Stop using electrical devices Stay away from water Get low to ground Stay in car

Which diagram best illustrates a map view of the motion of lower level winds in a Northern Hemisphere hurricane? 1. 2. 3. 4.

Which graph best shows the relationship between the category number of a hurricane and the expected damage from the storm? 1. 3. 2. 4.

The air mass that gave rise to Hurricane Gilbert would be identified as 1. m. T 2. c. T 3. m. P 4. c. P

What was the probable source of moisture for this hurricane? n n a. carbon dioxide from the atmosphere b. winds from the coastal deserts c. transpiration from tropical jungles d. evaporation from the ocean

When the eye of this hurricane reaches 43° N latitude, this hurricane will most likely be pushed by planetary winds toward the 1. Northwest 2. Northeast 3. Southwest 4. Southeast

Clouds form in the hurricane because the air is n n a. sinking, expanding, and cooling b. sinking, compressing, and warming c. rising, expanding, and cooling d. rising, compressing, and warming

The hurricane had maximum winds recorded at 110 miles per hour. Within a 24 -hour period, the hurricane moved 150 miles inland had maximum winds of only 65 miles per hour. State why the wind velocity of a hurricane decreased.