Presentation on theme: "Aviation Weather Dynamically Speaking"— Presentation transcript:
1Aviation Weather Dynamically Speaking +Materials: Beachball Globe, Cloud Charts+Collect Previous HW+ Came from Gleim and Kershner+It’s a very dynamic environment+Meteorology 101+Course Philosophy – Concepts, not minutia+“Weather Kills” – p 18 & 20 of Nall ReportWritten for the Notre Dame Pilot InitiativeBy the Pilots of the University of Notre Dame“Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”
2Dedication John H. Fischer, Cadet Captain, CAP Grandmother Prisoners of War / Missing In Action
3QuoteJust remember, if you crash because of weather, your funeral will be held on a sunny day. –Layton A. BennettWeather kills pilots, a lot of them. These 75 minutes will be some of the most important of the course.
5Lesson Plan Will learn Will be able to recite Atmosphere & Global CirculationWeather & ClimateClouds & StabilityWeather ForecastingWill be able to reciteAir Mass TypesLapse RatesStages of Thunderstorm DevelopmentTypes of Fog & CloudsWill be able to distinguishPictures of different cloud types
6The Atmosphere & Global Circulation “Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”
7Atmospheric Composition Earth's atmosphere has a unique composition of gases when compared to that of the other planets in the solar system.
8At greater altitudes, the same volume of air contains fewer molecules of the gases that make it up. This means that the density of air decreases with increasing altitude.
9At 7 miles, or FL350, the air is only ¼ dense of what it was At 7 miles, or FL350, the air is only ¼ dense of what it was. Hence, increased operating efficiency, less weather, and pressurizationThe earth's atmosphere thins rapidly with increasing altitude and is much closer to the earth than most people realize.
10Thermal Model of the Atmosphere Show how it curvesLinear to the tropopause about 2 degrees C per 1000 feetremains at –60 until outside the Ozone layerFor next slideWhat makes the atmosphere change? What is the cause?Wind caused by uneven heating
11Sunlight AngleOn a global, yearly basis, the equatorial region of the earth receives more direct incoming solar radiation than the higher latitudes. As a result, average temperatures are higher in the equatorial region and decrease with latitude toward both poles. This sets the stage for worldwide patterns of prevailing winds, high and low areas of atmospheric pressure, and climatic patterns.When you think of atmospheric changes, think heat.Uneven heating creates wind and pressure areas.Use Globe to show angle of sunlight
12Global Wind PatternsHot air rises over the equator due to the fact that it is less dense.This is called the intertropical convergence zoneThis rising air cools as it rises resulting in precipitation in the region of the ITCZ.The air then travels north and south at high altitude.Use globe to describe in 3-d what is happeningAir Goes North and south to fill vacuum created by air filling in for rising air
13Global Circulation With Globe, Coriolis Seasons – Have kid stand on table as sunChris Columbus - tradesWith Fan, demonstrate orthographic liftingCoriolis with Globe
14Global Wind PatternsHot air rises over the equator due to the fact that it is less dense.The cooled air descends to reach the surface at about 24 ON and 24 OS of the equator.This forms a high pressure areaThe great deserts of the world are located in this high pressure areaSahara, Saudi Arabia, Hawaii, MexicoGo back to previous slide to show the effect.
15Coriolis EffectDemonstrate throwing a ball off of a merry go around.
16An object in motion in the northern hemisphere appears to turn to the right. An object in motion in the southern hemisphere appears to turn to the left.
17Global Circ PixExplain WesterliesPart of the generalized global circulation pattern of the earth's atmosphere. The scale of upward movement of air above the intertropical convergence zone is exaggerated for clarity. The troposphere over the equator is thicker than elsewhere, reaching a height of about 12 mi.
18Air sinks over a high-pressure center that moves away from the center on the surface, veering to the right in the Northern Hemisphere to create a clockwise circulation pattern.Air moves toward a low-pressure center on the surface, rising over the center. As air moves toward the low-pressure center on the surface, it veers to the left in the Northern Hemisphere to create a counterclockwise circulation pattern.Pressure AreasEnd Atmosphere & Circulation Section
19Weather and Climate“Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”
20DefinitionConsider pix from NDWeather is a description of the changeable aspects of the atmosphere, the temperature, rainfall, pressure, and so forth, at a particular time. These changes usually affect your daily life one way or another, but some of them seem more inconvenient than others.
21Flying into Elkhart, Rwy 35 Notice the blade twist
22Air Masses Polar air mass Tropical Air Mass Continental Air Mass An air mass that moves from a cold regionTropical Air MassAn air mass that moves from a warm regionContinental Air MassMoves in from a land massMaritime Air MassMoves in from over an oceanHow have we defined these air masses then?
23Air Mass Types Temperature/Moisture Hot Cold Wet Tropical Maritime Polar MaritimeDryTropical ContinentalPolar ContinentalColdest temperatures = polar continentalMost Humid days = tropical maritime
24Current Weather Notice Hurricane & how it got pushed out of the way What goes here?Get Current Chart at weather.com
25Clouds and Stability“Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”
27How a Cloud Forms Temperature and Dewpoint Converge Water Condenses on Particles (Dirt, Dust, Smoke)Fog is a cloud very near to the surfaceGuess Bridge?Owl
28PrecipitationPrecipitation is water in the liquid or solid form that returns to the surface of the earth. The precipitation you see here is liquid, and each raindrop is made from billions of the tiny droplets that make up the clouds. The tiny droplets of clouds become precipitation by merging to form larger droplets or by the growth of ice crystals that melt while falling.Note Verga – precipitation that does not hit the groundNew Mexico Desert – Why is verga so common there?
29Condensation Nucleus (0.2 microns) Average Cloud Droplet (20 microns)Large Cloud Droplet (100 microns)Drizzle Droplet (300 microns)Average Rain Drop (2000 microns)Flying through a cloud is like flying through air, same consistencyClose the Vents when you fly through a cloudThis figure compares the size of the condensation nuclei to the size of typical condensation droplets. Note that 1 micron is 1/1,000 mm.
30Stability Air may be: Unstable (vertically) Cumulus clouds Stratus clouds
32Lapse RateAvg Lapse Rate = 2 deg C (3.5 deg F) / 1K !!! (Environment)In Thermal, it is 3 deg C (4.4 deg F) / 1KB/C of heat & expansionWho knows what 15 C = ? F (59 F)Got that math, now we start hauling through 60 picturesThe average lapse rate (rate of cooling) is 2° C per 1,000 feet or 3.5° F per 1,000 feetIn order to calculate the base of thermal driven cumulus clouds, divide the temperature / dewpoint spread by the lapse rate (4.4 ° F per 1,000 feet )
38Types of Fog Radiation (ground) fog Advection fog Requires windWarm air over cold land or waterUpslope (orographic) fogSteam fogLake or ocean source of waterCold air over warm waterPrecipitation fog (rain fog)Show slides of different types of Fog
39Radiation Fog From the Air Radiation found on calm nights, often under an inversion,Farmer’s Field – Driving on a clear road w/fog on sides
40Advection FogThree times now we’ve seen this picture. Isn’t it beautiful? Not if you’re going into SFO!Warm air over cold land or water
41Upslope FogOrographic Fog = Why mountains are often in clouds, air gets squeezed and moisture condensesWhich way is wind blowing?
43Steam Fog That’s a lake in the background Most types of fog form in stable atmospheric conditions. The exception is steam fog, shown in this picture of Maligne Lake, Alberta, Canada, just after sunrise in late summer. The land cools off overnight while the water retains heat from the summer. As the cooled air slips over the lake, heat and moisture are added from below, resulting in a fog that twists and writhes-- hence the term "steam fog".
44OrchardOrchards try to eliminate the inversionAnyone from FL?Fans like this one are used to mix the warmer, upper layers of air with the cooling air in the orchard on nights when frost is likely to form.
45Ice possible in the tops StratocumulusIce possible in the tops
54Thunderstorms Thunderstorms require T-storms always have lightning Unstable airMoistureLifting mechanismT-storms always have lightningThunder is the sound of lightningT-storms are reported when thunder is heardOnly true for manned observation postsAutomatic Reporting (AWOS) detects lightning dischargeNote reporting criteria OWLLightning is not that dangerous to an airplane, turbulence isNo such thing as heat lightningProper way to avoid getting struck by lightning = arms to kneesBoy Scout Tip of the Day
55Updrafts from thermals Three stages in the life of a thunderstorm cell. (A) The cumulus stage begins as warm, moist air is lifted in an unstable atmosphere. All the air movement is upward in this stage.
56Updrafts and downdrafts, starts when rain touches the ground (B) The mature stage begins when precipitation reaches the ground. This stage has updrafts and downdrafts side by side, which create violent turbulence.
57Only downdrafts“There is no reason to fly through a thunderstorm in peacetime.” –Sign over squadron ops desk at Davis-Monthan AFB, AZ(C) The final stage begins when all the updrafts have been cut off, and only downdrafts exist. This cuts off the supply of moisture, and the rain decreases as the thunderstorm dissipates. The anvil-shaped top is a characteristic sign of this stage.
58LightningDevelop charge from the friction between rising and falling air currents.Like scuffing across the floor and touching a metal ballDifferent parts of a thunderstorm cloud develop centers of electric charge. Lightning is a giant electric spark that discharges the accumulated charges.
59Thunderstorms Types of thunderstorms Air mass Frontal Upslope (orographic)Air Mass can often be sporadic and sparse but can reach upwards of FL600Frontal are usually more organized often as squall lines ahead of cold fronts, usually more powerfulUpslope often are only a problem on the upwind side while the lee remains in cool dry air (Sierra Nevadas or Cascades)
60HailHail most commonly thrown up to many miles from the anvil head of a t-stormThese hailstones fell from a thunderstorm in Iowa, damaging automobiles, structures, and crops.
61Cumulonimbus Distance to a Storm Thunderstorm Nimbus means rain 5 sec per mile at the speed of soundThunderstorm
62Bad IdeaThunderstorm from an MD-80 at 30,000 feet
64Boundaries between air masses = fronts Types of FrontsColdWarmStationaryOccludedThese are the four types of fronts
65Weather Fronts Front A boundary between two different air masses Cold FrontWhen a cold air mass moves into a warmer area, displacing the warm air massProvides lift to adiabatically cool the warm air, resulting in towering cumulus and thunderclouds.Blue Triangles on ChartsCold Air pushes under Warm Air forcing it upwardsSquall lines are areas of thunderstorms about miles ahead of a cold front
66A cold air mass is similar to a huge, flattened bubble of cold air that moves across the land. The front is the boundary between two air masses, a narrow transition zone of mixing.A front is represented by a line on a weather map, which shows the location of the front at ground level.Cold Front PixSee Kershner Chapter 22 for outstanding cross-sections of frontsNotice how the front aloft is many miles behind where it is on the ground
67When a warm air mass moves into an area, displacing the cold air mass Warm FrontWhen a warm air mass moves into an area, displacing the cold air massA gently sloping front as the Warm air moves over top of the cooler air.Stationary FrontWhen the edge of a front ceases to advanceRed Semicircles denote WarmRed and Blue denotes Stationary
68Warm Front PixAn idealized warm front, showing a warm air mass overriding and pushing cold air in front of it. Notice that the overriding warm air produces a predictable sequence of clouds far in advance of the moving front.
69Occluded Front One that has been lifted completely off the ground Has a low pressure center and cyclonic activityPurple TrianglesOften caused by a fast moving cold front overrunning a warm front
73CyclonesLCycloneA low pressure area with winds moving into the low pressure area and being forced upward.Friction and the Coriolis effect cause the air to move to the right of the direction of movement.AnticycloneA high pressure centerLows are usually in Red, Highs usually in BlueA very small L means a tropical depression.A severe tropical depression is a tropical storm/hurricane marked with a squiggleH
74Hurricane JohnThis is a satellite photo of hurricane John, showing the eye and counterclockwise motion
75Storm TracksNote SE track, trough tracks, and Alberta ClippersCyclonic storms usually follow principal storm tracks across the continental United States in a generally easterly direction. This makes it possible to predict where the low-pressure storm might move next.
76Weather Forecasting “Weather forecasts are horoscopes with numbers. “ “Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”
77Computer ModelsNote different models on left side
78Weather PredictionsWeather predictions are based on information about air masses, fronts, and associated pressure systems in an area.This information is used to produce a model of behavior for weather using a computer.Many models are used and then summarized when the different models agree fairly closely to a model of the weather.The closer the forecast is the more accurate it will be.Computes have taken an artform and forced a science upon it. A science that does not fit wellI laugh at the 10 day forecastsWhy do you think the weather channel has the money barometer (it’s easier to forecast the stock market!) They seem to have trouble predicting the past!
80PredictedNotice no storm in OK, weakened storm in Ontario and dissipating cold front on the Atlantic CoastActual
81Forecast for today????????? Add today’s forecast
82SupercomputersSupercomputers make routine weather forecasts possible by solving mathematical equations that describe changes in a mathematical model of the atmosphere. This "fish-eye" view was necessary to show all of this Cray supercomputer at CERN, the European Center of Particle Physics.
83Example of Atmospheric Refraction Home of the Flyin’ Irish!Aviation Weather, last slideSkyspotter HW due on THU (print certificate, or something)Where’s the pot of gold?