Weather: Exam 1
air pressure
to a significant degree, air pressure determines whether the day will be sunny and clear or cloudy and rainy
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water vapor is added to the atmosphere through evaporation from water surfaces - largely from warm ocean surfaces where the temperatures are highest
wind
wind speed and direction are related to differences in atmospheric pressure from place to place
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Solar energy is received unequally in space & time over the Earth's surface.
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a function of latitude
Major Elements/Building Blocks of Weather
air temperature humidity of the air type/amt. of cloudiness type/amt. of precipitation air pressure wind speed & direction
building blocks of weather
air temperature humidity of the air type/amt. of cloudiness type/amt. of precipitation air pressure wind speed & direction
humidity of air
air's ability to hold water vapor depends on the air temperature
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lower the air temperature, the lesser amount of water vapor the air can hold
meterology
study of the atmosphere & the processes that cause weather
clouds
there must first be water vapor in the air for clouds to form
Study slides 27-50
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Because isolines are lines of equal value, they do not divide, cross or intersect each other.
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Climate is NOT solely average weather - it deals with averages, extremes & variability of weather based on many years of day-to-day weather data.
cold fronts
Cold fronts occur where cold air advances into warm air and the warm air is forced upward.
air temp also influenced by
Earth surface material (land vs water) cloud cover ocean currents air mass movements altitude & aspect geographic position on the continent relative to the prevailing winds mountain barriers (or the lack of mountain barriers).
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High Pressure → Sinking Air → Air Warms → Air Can hold More Water Vapor → No Cloud Formation → Fair Skies
Heat energy exits the Earth system as the Earth's surface radiates heat back to space
However, certain gases in our atmosphere, called greenhouse gases, allow the lower atmosphere to absorb some of the energy radiated from the Earth's surface, trapping heat within the Earth system.
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If a location does not coincide with a isoline but is positioned between two different isolines, its value must be indicated as a range between the values of the bounded isolines.
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Isolines are drawn at fixed intervals; the value from one isoline to the adjacent isoline is always constant across an individual map.
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Isolines do not abruptly end; they always close on themselves, either on the map or beyond the map's boundary, in which case the isolines run to the edge of the map.
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Low Pressure → Rising Air → Air Cools → Air Can't Hold As Much Water Vapor → Clouds Form → Stormy Skies
earths energy from the sun
Sunlight travels through space & our atmosphere, heating up the land surface & the oceans. The warmed Earth then releases heat back into the atmosphere.
Climates will change if the factors that influence them change
To change climate on a global scale, either (1) the amount of heat that is let into the Earth's system changes, or (2) the amount of heat that is let out of the system changes.
weather goal
Ultimate goal of weather processes is to redistribute energy & attempt to balance it over the Earth's surface !
z time
Universal Coordinate Time (UTC) = Greenwich Mean Time (GMT) = Time at the Prime Meridian
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Values on one side of an isoline are higher than values on the opposite side of the line.
warm fronts
Warm fronts occur where warm air advances into a region of colder air and is lifted over the cold air.
The difference between weather and climate is a measure of time.
Weather is what the condition of the atmosphere is over a short time period, and climate is how the atmosphere "behaves" over relatively long periods of time (at least 30 years)
surface weather map
Weather maps are snap-shots of the atmosphere at a given time & all measurements shown on a given weather map were taken at the same time & that time is given as Greenwich Mean Time (0° long.) = Universal Coordinated Time (UTC) = Z-Time.
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Weather processes are Earth's quest toward energy equilibrium.
climate
an aggregate of day-to-day weather conditions over a long period of time (usually 30 years or more) at a locality an average pattern of weather for a particular region over a long period of time
elements
are interrelated; a change in one often brings about changes in the others.
isoline maps
are lines of equal value.
isoline maps
are lines on a map each of which connects points of equal value.
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as air containing water vapor rises, the air cools and eventually when the air gets cold enough, water vapor condenses (turns to liquid) or is deposited (turns to ice) - thus forming clouds
precepitation
by definition, all precipitation comes from clouds, and thus before precipitation occurs, there must first be water vapor in the air
cold fronts cont
clouds and precipitation occur over a narrow band, and may occur over minutes to hours. may be very heavy precipitation
warm fronts cont
clouds and precipitation occur over a wide band, and may occur over 1 to 2 days. usually light precipitation
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depends largely on the sun angle & length of daylight hours
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differences in air pressure set the air in motion winds blow from areas of higher pressure to areas of lower pressure
greenhouse gases
gases are necessary to warm the planet to a livable temperature, but increases in these gases due to human activities prevent less energy from easily escaping Earth to space, and the planet warms.
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greater the change in air pressure from place to place, the faster the winds will blow
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higher the temperature, the greater the amount of water vapor the air can potentially hold
air temp
largely a reflection of the amount/intensity of solar radiation reaching the Earth's surface
Major Controls of Weather & Climate
latitude - controls receipt of solar energy at a given location distribution of land & water elevation & large-scale topography ocean currents general atmospheric circulation & global distribution of lows & highs