Slide 1
Enduring UnderstandingEnergy transfer between the Earths surface and the atmosphere creates the weather.The atmosphere remains in balance until acted on by an outside force.
2WeatherWeather is the current state and short term variations in the state of the atmosphereTakes place over minutes, hours, days, weeks, months
3Causes of WeatherClimate is the long term variations for a particular areaAveraged over 30 years or more of weather data
4Redistribution of WealthWithout the atmosphere this energy imbalance would continue and the tropics would be very hot and the poles very cold year roundThe oceans store the majority of heat at Earths surface
5Redistribution of WealthTemperature differences in the air result in differences in density which the cause upward and downward movementThe convection currents of the atmosphere redistribute the heat energy as air over the warmer regions rises, cools, then descends over cooler regions.
6Redistribution of WealthThis movement causes weather
7Air MassesAn air mass is a large body of air that takes on the characteristics of the body over which it forms. They can form over either land or water and are classified according to their source regions
8Air MassesContinental Tropical (cT) air masses contain warm, dry air that forms over warm areas of landMaritime Tropical (mT) air masses contain warm, humid air that forms over warm areas of the oceanContinental Polar (cP) air masses contain cold, dry air that forms over cold areas of landMaritime Polar (mP) air masses contain cold, humid air that forms over cold areas of the oceanArctic (A) air masses are basically the same as cP, but much colder and are associated with extreme cold 9North American Source RegionsAll five main air mass types can be found in North America because of our close proximity to the source regions associated with each type of air mass
10North American Source RegionsContinental Tropical (cT) air forms over the desert of the southwest United States and Mexico
11North American Source RegionsMaritime Tropical (mT) air forms over the southern Atlantic, Gulf of Mexico, and southern Pacific oceans
12North American Source RegionsContinental Polar (cP) air forms over the interior of Canada and Alaska
13North American Source RegionsMaritime Polar (mP) air forms in the northern Pacific and Atlantic oceans
14North American Source RegionsArctic (A) air develops over the extreme northern regions of the continent
15Stability and Air Mass MovementAir masses do not stay in one place indefinitely. They move and transfer their heat from one area to another establishing a balance of heat throughout the planet
16Stability and Air Mass MovementAir mass modification occurs when the moving air mass changes to become more like the surface over which it travelsHeat and moisture are exchanged with the surface as the air mass travels over it
17Stability and Air Mass MovementEventually the air mass will become modified to the point it is indistinguishable from the new surface over which it is traveling and simply becomes part of the air over the new source region
18Coriolis effectThe Coriolis Effect on Earth causes moving particles (air molecules ) to deflect to the right in the northern hemisphere and to the left in the southern hemisphere
19Global Wind PatternsTrade Winds occur at where the warm, rising air from the equator begins to cool and sink. They occur below 30 degrees latitude and blow in an east to west direction
20Global Wind PatternsPrevailing Westerlies flow between 30 and 60 degrees latitude and blow from west to east. This pattern is responsible for much of the weather in North America
21Global Wind PatternsWinds are named for the direction they blow from
22Global Wind PatternsPolar Easterlies blow from east to west between 60 deg and the poles and are characterized by very cold air
23Global Wind Patterns
24Jet StreamsOften the weather report will state that the jet stream is affecting todays forecast in some way. Earth weather is strongly influenced by atmospheric conditions and events between the wind zones
25Jet StreamsJet Streams are narrow bands of fast, high-altitude, westerly winds and flow at speeds of 185 km/hrTheir position varies and drives large-scale weather systems
26FrontsSince air masses of different characteristics are constantly in motion some of them are bound to eventually collide
27FrontsFront is the narrow region separating two air masses of different densitiesDensity differences are caused by differences in temperature, pressure, and humidity
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29FrontsThere are four main types of fronts and the interaction of colliding air masses often causes dramatic changes in weather
30FrontsCold Fronts occur where cold, dense air displaces warm air and we see clouds, showers, and thunderstorms
31Fronts-Cold FrontGenerally, with the passage of a cold front, the temperature and humidity decrease, the pressure rises.
http://www.classzone.com/books/earth_science/terc/content/visualizations/es2002/es2002page01.cfm?chapter_no=visualization
32Cold Front-crossing NYS - October 2008 (metars and satellite)
33FrontsWarm Fronts are where advancing warm air displaces cold air and we see extensive cloudiness and precipitation
34Fronts-WarmGenerally, with the passage of a warm front, the temperature and humidity increase, the pressure decreases.
http://www.classzone.com/books/earth_science/terc/content/visualizations/es2002/es2002page01.cfm?chapter_no=visualization
35FrontsStationary Fronts are where the two air masses meet but neither advances. Little cloudiness and precipitation is seen
36FrontsOccluded Fronts occur where a cold air mass overtakes a warm front and wedges it upward. It then collides with another cold front and causes precipitation on both sides
37Fronts-OccludedOccluded front is formed when a cold front overtakes a warm front.
38Pressure SystemsThe vertical movement of air combined with the coriolis effect results in the formation of rotating low and high pressure systems
39High Pressure SystemHigh Pressure Systems are formed by dense, sinking air and move in a clockwise direction (in the northern hemisphere) High pressure is associated with fair weather
40Low Pressure SystemsLow Pressure Systems form by low density rising air moving in a counterclockwise directionLow pressure is associated with stormy weather
41Analyzing/Forecasting WeatherIn order to accurately analyze and forecast weather meteorologists must be able to reliably gather the necessary data about the atmosphere. The quality and amount of data available for a certain location greatly affect the outcome of the forecast
42The Instruments of MeteorologyThermometer measures temperature. They usually contain liquids such as mercury or alcohol that expand when heated
43The Instruments of MeteorologyBarometer measures air pressure. The common types are mercury and aneroid
44The Instruments of MeteorologyPsychrometer measures relative humidity. A wet and dry bulb thermometer is the most common type
45The Instruments of MeteorologyAnemometer measures wind velocity. The simplest type has cupped arms that rotate as the wind blows
46Technology in MeteorologyThe accuracy of weather forecasting has greatly improved over the last 40 years. Many technological advances from other sciences have been found to have practical applications in Meteorology
SunnyRainyCloudyMild47Technology in MeteorologyWeather Radar allows us to track real-time movement of precipitation inside the coverage area. Today most of the United States is covered by one or more weather radar sites
48Technology in Meteorology
49Technology in MeteorologyWeather Satellites take photographs and other images of the Earths surface at regular intervals.
50ImageryThese images are plotted and combined with radar data to determine where both clouds and precipitation are occurring
51Technology in MeteorologyInfrared Imagery is allows us to see temperature differences in the surface and moving air masses and allows us to predict a systems potential to produce severe weather
52Weather AnalysisOnce the weather observations are gathered meteorologists plot the data on a map using universally recognized symbols for the various pieces of information to be represented
53Weather AnalysisStation model is a record of the weather data for a particular site at a particular time and allows a large amount of data to be plotted in a small space
54Large Scale Weather Plotting Once the information for individual sites is plotted meteorologists can construct large scale (nationwide or worldwide) weather maps that represent the current state of the whole troposphere
55Large Scale Weather Plotting Isopleths are lines that connect equal or constant values and are similar to the contour lines used in geographyIsobars connect areas of equal air pressure
56Large Scale Weather PlottingIsotherms connect areas of equal temperature
57Short Term ForecastingWeather forecasting has improved much over the past few decades and continues to do so as we advance in our ability to obtain and process weather data
58Short Term ForecastingDigital Forecasts are the main method used by modern meteorologists. They rely on numerical data and are highly dependent on the density of data available. The more (accurate) data the more reliable the forecast
59Short Term ForecastingAnalog Forecasts compare current weather patterns to those that took place in the pastThe Farmers Almanac is an analog forecast
60Long Term Forecasting Regardless of the method used all forecasts become less reliable when they attempt to predict long term weather. Even high tech supercomputers cannot account for every factor that influences the weather and miscalculations are compounded with time
61Origin of the OceansSeveral geologic clues indicate that the oceans have existed almost since the beginning of geologic history
62Origin of the OceansThere are two general hypotheses about the origin of the Earths oceans
63Origin of the Oceans#1Comets and meteorites that impact the planet and release water
64Origin of the OceansMeteorites generally contain 5% water
65Origin of the Oceans#2Volcanism early in Earths history released significant amounts of water vapor among the other gasses to form the early atmosphere
66Origin of the OceansThe water vapor cooled and condensed to form the oceans
67Distribution of OceansThe oceans contain 97% of Earths water
68Distribution of OceansSea Level is the level of the oceans surfaces and has risen and fallen by hundreds of meters in response to expanding and receding glaciers
69The Major OceansThe oceans cover 71% of Earths surface. The landmasses are like islands completely surrounded by water.
70OceansThe five major oceans arePacificAtlanticIndianArcticSouthern (ANTARCTIC)
SeawaterThe water of the worlds ocean is undrinkable. Seawater is a solution of about 96.5% water and 3.5% dissolved salts
72Chemical Properties of SeawaterSalinity is the measure of the amount of dissolved salts in seawater
73Chemical Properties of SeawaterSalinity can vary between 3.2% and 3.7% depending on location, precipitation and temperature
74SeawaterAlthough sodium and chloride are the most abundant nearly all naturally occurring elements on Earth (including gold and silver) are found dissolved in seawater
75The Seafloor Continental margins are the submerged parts of the continents and are the shallowest parts of the oceans
76The Seafloor They include the continental shelf, and continental rise
77The Seafloor Continental Slope
78The Seafloor and Continental Rise
79The Seafloor Ocean basins lie beyond the continental margins and contain the abyssal plains
80The Seafloor Deep-sea trenches
81The Seafloor Mid-Ocean ridges
http://www.wwnorton.com/college/geo/oceansci/animations.asp
82The Seafloor and Hydrothermal vents
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