Transcript Temperature and Ground Hog day

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• Ground Hog Day - if the ground hog sees his shadow there will
be 6 more weeks of winter.
• German superstition used animals to predict weather. Germany
used a hedgehog.
• Pennsylvania - German settlements - 1887 - first ground hog
named Phil. Today is the 5th generation in Pennsylvania 7:00 a.m. Penn. Time in Globber Hill -Ground Hog Club. A
very big tradition - people dress up and many tourists come to
see the festival. Ground Hogs usually hibernate. They are
woken up for the tradition. Phil is about 14 pounds.
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•Atmospheric Properties that
describe weather conditions
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• Temperature vs. Heat - Temperature measures how rapidly or
slowly molecules move around.
• Heat is the transfer of energy because of difference of
temperature between substances.
• Temperature Scales:
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• Meteorology – study of atmospheric phenomena
Greek meaning of Meteors – high in the air
Types of atmospheric meteors
Clouds, raindrops, snow flakes, fog, dust, rainbows
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• Lithometeors- smoke, haze, dust
• Electrometeors- thunder, lightning
• Weather – current state of atmosphere.
• Climate – long term variation – determine over 30 years span
or more.
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• Temperature is constant there. Why?
• Through constant motion of air and water relocation
• Air masses – large body of air that takes on the characteristics
of the area in which it formed (Source Region).
• Land Air masses – less moisture
• Water Air Masses – more moisture ( high evap.)
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According to source region
(CT) Continental Tropical –warm and dry
(MT) Martime Tropical – warm and humid
(CP) Continental polar – cold and dry
(MP) Maritime polar – cold and humid
( A) Arctic – Much colder – same as continental polar air masses
associated with very high pressure.
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• 5 main types of air masses in the U.S. – due to the continents
location to the source regions associated with each air mass.
• Maritime polar (California) –Forms over the North Atlantic and
North Pacific.
• This is why we have heavy rains in the winter.
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• Continental Polar- freezes the middle /Northern part of the U.S.
Forms over the interior of Canada and Alaska.
Maritime Tropical Air – forms in tropical and subtropical oceans (
Caribbean Sea and Gulf of Mexico)
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• Maritime Tropical Air- forms in the Western U.S.
Summer brings hot humid weather to the eastern 2/3 of the U.S.
and Canada.
• Continental Tropical Air – Desert Southwest and Mexico and
source region , Hot/Dry
• Arctic- Develops over latitudes of 60 N
Ice Regions of Siberia and Arctic Basin
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• As air masses move over the surface of the earth, they acquire
the characteristics of other source regions, In time loses it’s
identity.
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Weather systems- earth rotates around the sun ,
The rotations causes the Coriolis Effect.
S, Hemisphere: deflect to left
N Hemisphere : deflect to right
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• This cell creates a belt of high pressure.
• It causes weak surface winds.
• Called Horse Latitude
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• Inter Tropical Convergence Zone
Air converges and is formed upward.
Area of low pressure forms over a large area.
Low pressure migrates wit movement of the sun’s rays.
Weather is normally cloudy with showers. Great for the tropical
rain forest.
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• Between 30 * N and 30* S
• Air sinks, warms and moves back toward 30* and sinks again (
warm air rises, cold air sinks). Example of a Convection cell.
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• Located between 30* and 60*
• They move opposite of Trade winds.
The winds blow towards the poles in an easterly direction(
blows for west to east)
Responsible for the weather for the U.S.
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• Lies 60 * N and 60* S
• Characterized by cold air.
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• Narrow band of fast, high altitude westerly winds
• Speed are up to 185 km/hr
2 Jet Streams
Polar Jet – separates Easterlies from prevailing westerlies.
Subtropical Jet Stream-Where trade winds meet prevailing
westerlies.
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Cold dense air replaces warm air forcing it upward. ‘
Warm air condenses as cooling
Clouds, showers and thunderstorms associated
The Front moves fast so a steep front develop
The points on the symbol indicates the directional movement.
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• Warm air displaces the cold air
• Warm front is a gradual slope due to the air in front moving
slower.
• The warm front encounters less friction
Weather is extensive cloudiness and precipitation.
Points on the symbol point in the directional movement.
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• The meeting of two air masses and neither is moving in a
direction.
• Occurs due to modifications that have occurred there is little
imbalances.
• Weather patterns are similar to a warm front.
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• Cloud air mass moves so rapidly it overtakes a warm front
• Cold air mass wedge pushes the warm air upwards.
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• Rising air associated with low pressure
• Sinking air associated with high pressure
Weather is basically rotating High and low pressure produced by
rising and sinking air combined with the Coriolis effect
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• Air sinks
• The air reaches the surface and spreads out
• Air is deflected to the right or clockwise in the Northern
Hemisphere. It rotates to the counter clockwise in the Southern
Hemisphere.
• Associated with cold air masses, fair weather
• Found in subtropical oceans
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• Air rises and is replaced by air from outside the system so it
flows toward the center.
• Weather is cloudy and precipitation
• Found in the middle latitudes
• Wave cyclone begins along a stationary front
Imbalances occur and pushes the front south and another part
north.
Weather produced affects large areas.
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• Saturation - point at which air holds as much H 2O vapor as
possible. Condensation cannot happen until saturation is
reached.
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• H2O vapor changes to liquid (rain)
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• As air masses rise over, mountains tend to cool. Remember
clouds are suspended H2O vapor. As cloud rises, temperature
cool then condensation temperature reach LCL (lifted
condensation level) base level of clouds. Above LCL air
becomes saturated and cools more slowly. The rate that
saturated air cools is called the moist adiabatic lapse rate.
• Range - 4°C/1000m to 9°C/1000m
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(warm air)
(cold air)
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• temperature; air pressure; wind; relative humidity to make
accurate weather forecasts
• The two most important factors of weather forecasting are:
accuracy and density of data
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• Thermometers - measures temperature - heights of liquid
column indicates temperature from the expansion of the liquid.
There are two types: mercury and alcohol.
• Barometer - measures air pressure. There are two types:
• mercury barometer - air pressure changes with the height of
the mercury.
• aneroid barometer - metal container with a vacuum chamber
inside. This chamber contracts or expands with changes in air
pressure.
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• Radioscope - measures upper level data - temperature, pressure,
and humidity.
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• Doppler Radar - measures wave frequency that occurs in energy
such as sound and Light Data is plotted - indicates wind speed and
the movement of the front.
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• Weather satellites - takes a picture of earth at regular intervals
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• Infrared Imagery - used to measure surface temperature difference.
* Detects strong thunderstorms.
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Station Model - Record of weather data for a particular site
• Allow meteorologists to fit a large amount of date into a small
space
• Provides a uniform way of communicating:
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• Isopleths - lines connecting points of equal or constant values
• Isobars - lines of equal pressure
• Isotherms - line of equal temperature
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Barometric -
Pressure
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Isobars are close together - strong winds
Isobars are far apart - calm winds
Reliable forecast must rely on analyzed date from different levels of the atmosphere
Digital forecast - Forecasts that are ones that rely on numerical data. Highly
Dependent on the density of data - main method used
Analog forecast - comparing current weather patterns to the past. Used for monthly and seasonal forecasts
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