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Weather
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Weather is …. The condition of the variables in the atmosphere at a given time and place. Variables – temp, air pressure, wind, cloud cover, precipitation, etc.
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Measuring Temperature
3 different scales to measure temp. Celsius Fahrenheit Kelvin ESRT pg 295 (13)
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Temp is …. Measured using a thermometer (liquid filled glass tube)
Modeled on maps or charts by using isolines (isotherms)
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The atmosphere is heated in many ways:
Insolation from the Sun Conduction Condensation Coriolis effect
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Heat energy is transferred in our atmosphere by the process of convection.
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A closer look at CONVECTION:
Transfer of heat energy through substances which can flow. A closer look at CONVECTION: water A convection cycle air Molten rock 5. Rising heated water moves outward to replace sinking cooler water. 4. Cooler more dense water sinks. 2. Lower density warmer water rises upward. 3. Water moves in to replace rising warm water Heat source 1. Heating causes a decrease in density
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Air Pressure Air Pressure- Pressure due to weight of the overlying atmosphere pushing down on a given area. Pressure & Density are directly related Density = Pressure
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Measuring Air Pressure
Barometers Mercury barometer Standard reference but difficult to transport (inches of mercury) Aneroid barometer Non-liquid barometer that is smaller (millibars)
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ESRT pg 295 (13) mb = ________ inches mb = ________ inches 30.53 inches = ________ mb 29.81 inches = ________ mb 29.92 30.18 1034.0 1009.5
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What Effects Air Pressure?
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As the temp of air increases the density & pressure _____________
As the altitude increases the density & pressure _______________ decreases decreases
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The greater the amount of water vapor, the lower the air pressure & density…. but WHY?
Water has less mass than other elements, which it replaces in the atmosphere.
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Practice Questions According to the Earth Science Reference Tables, an air pressure of inches of mercury is equal to mb mb mb mb
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A balloon carrying weather instruments is released at the Earth’s surface & rises through the troposphere. As the balloon rises, what will the instruments generally indicate? 1. An increase in both air temp. & air pressure 2. A decrease in air temp. & an increase in air pressure 3. An increase in air temp. & a decrease in air pressure 4. A decrease in both air temp and air pressure
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A temperature of 80°F would be approximately equal to how many degrees on the Celsius scale?
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Layers of our Atmosphere
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Where was he? Jumped from 128,000 feet, or 24 miles!
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Mapping Temperature and Air Pressure
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Why Use Weather Maps? Weather maps help us picture what is going on in the atmosphere. Data is collected in multiple locations, and is displayed in a format that can be understood easily by people. The information is placed on weather maps.
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Isolines Connect points of equal value on a map. Ex.: Temperature, Pressure, Elevation.
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Types of Isolines Isotherms – connect points of equal temperature.
Isobars – connect points of equal air pressure.
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Rules For Drawing Isolines
Isolines begin and end at the edges of the map OR form closed circles. Isolines connect points of equal value. The isoline interval is the difference between two neighboring isolines. Isolines NEVER cross because the point of intersection would have two values, and this cannot happen.
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Gradient Gradient – Shows how much something changes over a distance.
Calculating Gradient: Gradient = Change in field value Distance
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Wind 10 windiest cities Avg annual wind speed in mph RANDOM FACTS:
Horizontal movement of air parallel to earth’s surface 10 windiest cities Avg annual wind speed in mph 1. Blue Hill, Ma 15.4 2. Dodge City, Kansas 14.0 3. Amarillo, Texas 13.5 4. Rochester, Mn 13.1 5. Casper, Wyoming 12.9 6. Cheyenne, Wy 7. Great Falls, Montana 12.7 8. Goodland, Kansas 12.6 9. Boston, Ma 12.5 10. Lubbock, Texas 12.4 RANDOM FACTS: Fastest wind struck Oklahoma City on May 3, 1999. (SPEED was 318 mph) Two of the windiest cities are found in Massachusetts
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ANEMOMETER – Instrument used to measure wind speed
-Measured in miles per hour & knots
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Caused by DIFFERENCES in air pressures for a specific distance
AIR PRESSURE GRADIENT CLOSER THE ISOBARS = GREATER Pressure Gradient & FASTER Wind Speed
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WIND MOVES FROM: Areas of HIGH pressure to areas of LOW pressure Coriolis effect (Earth’s rotation) causes winds to move.. -RIGHT Northern Hemisphere -LEFT Southern Hemisphere
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MYTH OF THE TOILET One can find both counterclockwise and
clockwise flowing drains in both hemispheres. Some people would like you to believe that the Coriolis force affects the flow of water down the drain in sinks, bathtubs, or toilet bowls. Don’t believe them! The Coriolis force DOES NOT affect such small bodies of water
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Planetary winds in the Troposphere
Unequal heating of Earth causes huge CONVECTION CELLS around Earth
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ESRT pg. 14 Sinking Drier Air Rising Moist Air Sinking Drier Air
HIGH LOW Sinking Drier Air HIGH ESRT pg. 14 Rising Moist Air LOW HIGH Sinking Drier Air LOW HIGH Rising Moist Air Sinking Drier Air
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Closer Look
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Bands of easterly moving air at the top of the troposphere called JET STREAMS
-Blow 200 miles an hour or more
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Local Breezes SEA BREEZE LAND BREEZE
Air blows from the sea onto the land during the day LAND BREEZE Air blows from the land out to sea at night
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Surface Ocean Currents
Caused by wind blowing over the oceans & transferring energy to the water DIRECTION of CURRENTS is affected by: 1) PLANETARY WIND BELTS 2) ROTATION of EARTH 3) BLOCKING BY LANDMASSES
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High Pressure System AKA - anticyclones Highest Pressure in CENTER
Winds blow OUT Winds move CLOCKWISE High and Dry!
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Low Pressure System AKA - Cyclones Lowest Pressure in CENTER
Winds blow TOWARDS the center WINDS move COUNTERCLOCKWISE LOUSY DAY!!
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Two weather stations are located near each
other. The air pressure at each station is changing so that the difference between the pressures is increasing. The wind speed between these 2 locations will probably (1) decrease (2) increase (3) remain the same
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On which side of the low-pressure center will the wind speed be greatest?
(1) North (2) South (3) East (4) west
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Which location is experiencing a southwest planetary wind?
B C F
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Which location is near the center of a low-pressure belt where daily rains, are common?
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**Gaseous water in the atmosphere is called WATER VAPOR**
Atmospheric Moisture Amount of moisture in the air is constantly changing 3 STATES of MATTER: 1) LIQUID 2) SOLID 3) GAS **Gaseous water in the atmosphere is called WATER VAPOR**
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PLANTS release water vapor
Water vapor enters the atmosphere by: EVAPORATION LIQUID changes to GAS TRANSPIRATION PLANTS release water vapor
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Change of phase from SOLID to GAS
SUBLIMATION Change of phase from SOLID to GAS (NO LIQUID PHASE)
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Factors INCREASING Evaporation:
1) MORE ENERGY available 2) INCREASE in SURFACE AREA of the water 3) GREATER WIND SPEED Factors DECREASING Evaporation: 1) INCREASE in SATURATION of the air
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Humidity ABSOLUTE HUMIDITY – AMOUNT of water vapor present in the air
MOISTURE CAPACITY – TOTAL amount of water vapor the air can hold RELATIVE HUMIDITY – Ratio between the amount of moisture in the air with the amount the air can actually hold at that temperature
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Relative Humidity & Temperature
HOT AIR HOLDS MORE MOISTURE THAN COLD AIR
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EXAMPLES: 1) Temperature _______________but amount of water vapor remains the SAME, then the Relative Humidity will _______________. INCREASES DECREASES DECREASES 2) Temperature _________________ but amount of water vapor remains the SAME, then the Relative Humidity will __________________. INCREASES 3) Temperature remains the SAME, but MORE water vapor is added, then the Relative Humidity will __________________. INCREASES
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Determining Relative Humidity
-Instrument used to measure called a PSYCHROMETER Smaller the difference between the dry & wet bulb temperature the more humid the air
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Dew Point Temperature at which the air becomes SATURATED with water vapor & the RELATIVE HUMIDITY is 100% Air drops TO the dew point condensation will occur (CLOUDS FORM)
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Determining Dew point on Chart
Dew point = 1oC Assume a dry-bulb temperature of 10oC & a wet-bulb temperature of 6oC. The difference between these two readings is 4oC. Pg. 12
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Relative Humidity = 54%
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The graph indicates that as the air temperature increases, the relative humidity Decreases, only Increases, only Increases & decreases Remains the same
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Condensation most likely occurred at approximately
(1) 6 am (2) 9 am (3) 7 pm (4) 10 pm
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The dry-bulb temperature is 20oC. The wet-bulb temperature is 17oC
The dry-bulb temperature is 20oC. The wet-bulb temperature is 17oC. What is the dew point? (1) 12oC (2) 13oC (3) 14oC (4) 15oC
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When was the air at ground level SATURATED with water vapor?
(1) 6 pm MONDAY (2) 6 am Tuesday (3) 3 pm TUESDAY (4) 12 noon Tuesday
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The relative humidity was lowest at
(1) 12 midnight (2) 6 am (3) 12 noon (4) 3 pm
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Station Model Open your ESRT to pg 13
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Precipitation (inches)
Cloud Cover Temperature (°F) Barometric Pressure Visibility (miles) Barometric Trend Present Weather 5 = / 65 .1 Dew Point (°F) Wind Speed Precipitation (inches) Wind Direction
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Decoding Barometric Pressure
If the number given is higher than 500 put a 9 in front and add a decimal in between the last 2 numbers. Example: 642 ___________ 972 ___________ 980 ___________ 964.2 997.2 998.0
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If the number given is lower than 500 put a 10 in front and add a decimal in between the last 2 numbers. Example: 320 ___________ 240 ___________ 040 ___________ 1032.0 1024.0 1004.0
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Encoding Barometric Pressure
Example: mb a. Drop the decimal point = 10137 b. Report the last 3 digits = 137 Practice: _____________ ____________ 160 840
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Understanding Barometric Trend
SYMBOLS + pressure was HIGHER than 3 hours ago pressure was LOWER than 3 hours ago / pressure is rising \ pressure is falling - pressure is steady Number decimal point is missing Example: 32 = 3.2
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Practice Question Pressure = 230 Trend = + 34 / ____________________
1023.0 Higher 3.4 mB – 3.4 = Still Rising
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35 199 8 +31 / 10 .03 a. Wind Direction ____________ Northwest
/ a. Wind Direction ____________ Northwest 15 knots b. Wind Speed ____________ 35°F c. Temperature ________________ 10°F d. Dew point Temperature _________ mb e. Barometric Pressure ____________ f. Barometric Trend ______________ 3.1 & Rising g. Cloud Cover _________________ 0%
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AIR MASS –Large body of air in the troposphere with similar characteristics of PRESSURE, MOISTURE, & TEMPERATURE
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Forms when a large mass of air remains STATIONARY for a period of time acquiring similar characteristics.
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Temperature: High Latitude _____________ Low Latitude ______________ Humidity: Land _____________ Water _____________ Low Temp High Temp Dry Air Wet Air
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m = maritime (water, wet) c = continental (land, dry)
T = Tropical P = Polar (low latitudes & hot) (high latitudes & cold)
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Tornado Alley
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Cold air is pushing forward into warmer air.
Cold Front Cold air is pushing forward into warmer air.
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Cold Front Strong storms can occur, such as thunderstorms.
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Warm air is pushing forward into colder air.
Warm Front Warm air is pushing forward into colder air.
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Warm Front Steady rain can occur leading up to the warm front.
High elevation clouds are seen ahead of the warm front.
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Why is precipitation associated with fronts?
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Adiabatic Heating and Cooling
Adiabatic Cooling When air rises, it expands, and the temperature of the air decreases. Adiabatic Heating When air sinks, it condenses, and the temperature of the air increases.
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Elevation Elevation increases, the air becomes less dense and expands.
Less-dense air cannot hold as much HEAT Elevation = Temperature
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Precipitation at High Elevation
The air reaches its dew point Condensation forms clouds Precipitation starts to fall
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Cold air is pushing forward into warmer air.
Cold Front Cold air is pushing forward into warmer air.
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Warm air is pushing forward into colder air.
Warm Front Warm air is pushing forward into colder air.
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Occluded Front Warm Air Warm Air
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Both cold & warm air are pushing forward
Stationary Front Both cold & warm air are pushing forward
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Practice Questions A mT airmass would most likely originate over which type of Earth surface? A) warm and moist B) cold and dry C) cold and moist D) warm and dry
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Which map correctly shows the wind directions of the high-pressure and low-pressure systems?
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The cold frontal interface is moving faster than the
warm frontal interface. What usually happens to the warm air that is between the two frontal surfaces? A) Warm air is forced under both frontal interfaces. B) Warm air is forced under the cold frontal interface but over the warm frontal interface. C) Warm air is forced under the cold frontal interface but under the warm frontal interface. D) Warm air is forced over both frontal interfaces.
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4. Compared to a maritime tropical airmass, a maritime polar airmass has
A) lower temperature and less water vapor B) higher temperature and less water vapor C) lower temperature and more water vapor D) higher temperature and more water vapor
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5. How does air circulate within a cyclone (low pressure area) in the Northern Hemisphere?
A) counterclockwise and away from the center of the cyclone B) clockwise and away from the center of the cyclone C) counterclockwise and toward the center of the cyclone D) clockwise and toward the center of the cyclone
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Station WANTAGH CEDAR CREEK Distance 5.3 miles Jan Temp 24 to 37 F Apr Temp 40 to 55 F Jul Temp 67 to 81 F Oct Temp 47 to 62 F Annual Precip 42.9 inches Climate: the overall view of a region’s weather conditions over a long period of time
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JFK
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The two main factors that determine climate are
Temperature Precipitation Annual Temp Range – difference between average temp of the hottest month & the coldest month
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Arid or Dry when… precipitation is less than the need Humid or Wet when… Precipitation is more than the need
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World Climate Map
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Latitude Temp varies with latitude because of the relationship between the angle of insolation & duration of sunlight
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Low Latitudes -Sun usually HIGHEST in sky average temp. is always high High Latitudes Sun usually LOWER in sky average temp. is low
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**Wet & Dry Belts are in the ESRT Pg 14 (296)**
Moisture **Wet & Dry Belts are in the ESRT Pg 14 (296)** Moisture varies because of planetary winds & pressure belts Low Pressure – ___________ High Pressure – Humid Climates Dry Climates
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Practice Questions A high air-pressure, dry-climate belt is located at which Earth latitude? A) 30°N B) 15°N C) 0° D) 60°N
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The planetary wind & moisture belts indicate that large amounts of rainfall occur at Earth’s equator because air at Earth’s surface is A) Converging & rising B) Converging & sinking C) Diverging & rising D) Diverging & sinking
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An area with a high potential for evapotranspiration has little actual evapotranspiration and precipitation. The climate of this area is best described as A) cold and arid B) hot and humid C) cold and humid D) hot and arid
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Which generally has the greatest effect in determining the climate of an area?
A) Degrees of longitude B) Extent of vegetation C) Distance from the equator D) Month of the year
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According to the ESRT, at which of these latitudes would average annual precipitation be greatest?
A) 90°S B) 90°N C) 30°N D) 0°
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Large Bodies of Water Lake, ocean, seas modify climate patterns
Water takes time to HEAT up & COOL down because it has a HIGHER SPECIFIC HEAT Specific Heat – The amount of energy it takes to raise 1 gram of water by 1 degree Celsius.
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Cooler Summers & Warmer Winters
MARINE CLIMATE Cooler Summers & Warmer Winters -Small annual temperature range CONTINENTAL CLIMATE Cooler winters & warmer summers -Large annual temperature range
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Causes WARMER Climates & MORE precipitation
Ocean Currents Currents flowing away from the equator carry WARM water to higher latitudes Causes WARMER Climates & MORE precipitation -
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COOLER climates with LESS precipitation
Currents flowing toward the equator carry COOL water to lower latitudes COOLER climates with LESS precipitation
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Prevailing Winds U.S. located in the prevailing southwesterly wind belt Weather moves from Southwest to Northeast CALIFORNIA has more of marine climate because prevailing winds blowing from the coast
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Weather changes caused by the seasonal shifts of Prevailing Winds
MONSOONS Weather changes caused by the seasonal shifts of Prevailing Winds -Mostly associated with southeast Asia causing wet summers & dry winters
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El Nino El Nino ANIMATION
-Periods of ocean WARMING along the Pacific coast of South America
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Which graph best represents the yearly temperature variation for location B?
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Which location probably has the highest average yearly temperature?
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Why are temperature variations usually not as great on Long Island as they are in central NYS?
Central NYS has a higher elevation Central NYS is more heavily wooded Long Island has a more southerly latitude Long Island is surrounded by a large body of water
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According to this diagram, between which 2 latitudes are the prevailing southwesterly winds located?
2) 30°N and 0° 30°N & 60°N 4) 30°S and 60°S 3) 30°S and 0°
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Elevation Elevation increases, the air becomes less dense and expands.
Less-dense air cannot hold as much HEAT Elevation = Temperature
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Precipitation at High Elevation
The air reaches its dew point Condensation forms clouds Precipitation starts to fall
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Mount Kilimanjaro
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Mountains There are two sides to a mountain range: Windward
The side that faces oncoming winds Rain or snow fall in this side
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Leeward The downside of the mountain Dry air, sometimes called the rain shadow Often times you will find a desert located here
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Vegetation Forests are cut down, deforestation, more ____________ occurs RUNOFF Without trees to absorb solar energy from sun: -SUN heats the land & atmosphere faster Summer cooler under the shade of a tree
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Cloud Cover DURING DAY LESS CLOUDS the more heat reaches the Earth from the sun AT NIGHT Yuma Arizona, is the top ten sunniest place in the world They have on average 242 clear days while we have only 96 clear days on average – there average temperature is 74.2 degrees F and ours is 54.3 degrees F 175 days of temps over 90 we only have about 15 Elevation 210 feet here we are about 24 feet above sea level LESS CLOUDS the more heat is released at night
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Practice Questions Which graph best shows the general effect that differences in elevation above sea level have on the average annual temperature?
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Location G has a cold, humid climate
Location G has a cold, humid climate. Which profile best represents the position of location G with respect to the mountains & the prevailing winds?
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The map below shows the location of four cities A, B, C, & D, in the western US where prevailing winds are from the southwest. Which city most likely receives the least amount of average yearly precipitation? A) A B) B C) C D) D
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What is the best explanation for the two statements below?
* Some mountains located near the Earth's Equator have snow-covered peaks. *Icecaps exist at the Earth's poles. A) Both mountain & polar regions have arid climates. B) An increase in snowfall & an increase in temperature have a similar effect on climate. C) Mountain & polar regions receive more energy from the Sun than other regions do. D) High elevation & high latitude have a similar effect on climate.
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In the diagram of a mountain below, location A & B have the same elevation.
Compared to the climate at location A the climate at B will be Warmer & drier C) Warmer & wetter Cooler & drier D) Cooler & wetter
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Phase Changes Of Matter
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Melting and Freezing
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Evaporation and Condensation
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DRAW Gas Vaporization Temperature Condensing Liquid Melting Freezing
Heat Energy Gas Vaporization Condensing Liquid Melting Freezing DRAW Solid
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Changing of State of Matter
When water is changing state of matter the temp remains the same
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