Intro to Meteorology: Our AtmospherePresentation Transcript
(Not on Notes Page…)Meteorology – the study of atmospheric phenomena(weather and climate).•“Meteor” is derived from ancient Greek meaning “high inthe air.”•Clouds, raindrops, dust, fog, and rainbows are atmospheric“meteors.”
Weather – the current state of theatmosphere.What is the weather in our area?Climate – the long term average stateQ: What is the climate in Hawaii? Alaska?
Earth’s AtmosphereThis is an image of the sunrise from space over the South China Sea.An astronaut would see something like this; clearly defined bands ofcolor through the atmosphere as the sun rises. The brightness of thecolors in the atmosphere in this photograph is due to the amount ofdust in the atmosphere.
Development of the Atmosphere Early Atmosphere• During the 1st billion years of Earth’s formation, there was a lot of volcanic activity (Outgassing). •Released water vapor (H2O), chlorine (Cl), carbon dioxide (CO2), hydrogen (H), and nitrogen (N). •The Past Atmosphere: Billions of years ago the Earth’s atmosphere contained two deadly gases: Ammonia (NH3) and Methane (CH4). •NO OXYGEN YET!
•After several million years, the planet cooled,water vapor condensed and absorbed most of thecarbon dioxide.•Storm clouds formed that produced heavy rainswhich formed the first oceans.•It is believed that some of Earth’s water mayhave originated from numerous collisions withsmall collisions with small meteors anddisintegrating comets* when the Earth wasyoung.*carbon dioxide, methane and water with dust and various mineral aggregates
How did the atmosphere becomesafe for us?1) Oxygen was formed from thedissociation of water molecules andby photosynthesis of primitivebacteria called cyanobacteria. Thisblue-green bacteria appeared 3.5billion years ago and triggered therelease oxygen as a waste product onearth.
Where did the oxygen come from cont…2) By a slow increase in concentration as rays from thesun split water vapor (H20) into hydrogen and oxygen.•Hydrogen (H) drifted off to space, while Oxygen (O) remainedin the atmosphere.3) Plants also contributed to the formation of oxygen(photosynthesis: the process of using energy in sunlight toconvert water and carbon dioxide into carbohydrates (sugars)and oxygen.
This image shows the average temperature profile through theEarths atmosphere.
To Santa: MORE TOY ELEPHANTS!
Layers of the Atmosphere:The atmosphere surrounds Earth andprotects us by blocking outdangerous rays from the sun. Theatmosphere is a mixture of gases thatbecomes thinner until it graduallyreaches space. It is composed ofNitrogen (78%), Oxygen (21%),and other gases (1%). Also, itcontains dust and salt, which isimportant for the formation ofclouds.
The atmosphere is dividedinto five layers. It is thickestnear the surface and thins outwith height until it eventuallymerges with space.
1. The Troposphere•The lowest layer of the Earths atmosphere.•Temperature decreases as height increases (3.6degrees/1000 ft).•Most dense (due to compaction of molecules).•Around the equator, the height is about 16 km.•air is slightly unstable.•ALL WEATHER occurs in the Earthstroposphere!!!•0 – 11 miles up.
This is an image of the clouds in the Earths troposphere.
2. The Stratosphere•Altitude of 50 km. (11 miles to 30 miles).•On Earth, ozone causes the increasingtemperature in the stratosphere. Ozone isconcentrated around an altitude of 25kilometers. The ozone molecules absorbdangerous kinds of sunlight, which heatsthe air around them.Many jet aircrafts fly in the stratospherebecause it is very stable.
If ozone is decreased, it can cause: Skin cancer Eye cataracts Sun burning Suppression of the human immune system. Adverse impact on crops and animals due to the increase of UV radiation A reduction of ocean phytoplankton.
Polar stratospheric clouds, also known as
3. The Mesosphere•Temperature decreases with altitude. (30 – 55 miles)•The atmosphere reaches its coldest temperature ofaround -100°C in the mesosphere.•Air pressure decreases.•Does not have a lot of oxygen (at this level ourbrain would be oxygen-starved called hypoxia.•This is also the layer in which a lot of meteors burnup while entering the Earths atmosphere.
4. The Thermosphere• 55 – 80 miles up.The “warm layer.” This is due to the Omolecules absorbing solar rays, heating the air.• When the sun is active, the thermosphere canheat up to 2,000°C or higher!• includes the region of the atmosphere calledthe ionosphere. The ionosphere is a region ofthe atmosphere that is filled with chargedparticles (ions).• Important for radio communication.
The space shuttle orbits in thethermosphere of the earth.
5. The Exosphere•Very high up, the Earths atmospherebecomes very thin. The region whereatoms and molecules escape into space isreferred to as the exosphere.•The exosphere is upper part of thethermosphere.•Extends about 550 km above thesurface. (80 miles and up!)•Satellites orbit in the exosphere.
This is a picture which shows the Earth, its atmosphere (theclouds are likely in the troposphere and stratosphere), the limb ofthe Earth (the dark blue curve/edge which is the mesosphere andthermosphere), and the dark blue to black region of space (whereour exosphere extends out to...).
•It is made up of positively chargedprotons and negatively chargedelectrons. The Earth is a large magnet.
•Van Allen radiation belts: the charged particles that areconcentrated into belts, or layers of high radiation.•When there is a solar flare, it is bombarded with electricallycharges particles. Aurora borealis or northern lights.
Comet Hale-Bopp in the 29 March 1997
Solar Fundamentals (Energy transfer) 3 ways:Why Learn? Uneven heating of the Earth causes weather!1) Radiation – transfer of energy through space by visible light, electromagnetic waves, and ultraviolet waves. Earth absorbs and reflects this energy. Sunlight is a form of radiation that is radiated through space to our planet without the aid of fluids or solids.
Radiation 20 sec
2) Convection – transfer of energy due to heat flow.• Hot air rises, cold air sinks (density)!• Affects weather.*Hot substances are less dense than cold substances.*Cool substances are more dense than hot substances.EX. Mantle convection, wind, and wind drafts.
Convection in the oceans…
Convection 53 sec
3) Conduction - is the process by which heat energy is transmitted through contact with neighboring molecules (substances – solids, liquids, and gas).• Some solids, such as metals, are good conductors of heat while others, such as wood, are poor conductors. Air and water are relatively poor conductors.• Since air is a poor conductor, most energy transfer by conduction occurs right at the earths surface. At night, the ground cools and the cold ground conducts heat away from the adjacent air. •Heat ALWAYS travels from warmer areas to cooler areas. •Examples?
Conduction 54 sec
How does this relate to our weather? Let’s tie it all together: radiation, convection, and conduction.•During the day, solar radiation heats the ground, which heats the airnext to it by conduction, which can form convection currents.
1. Construct a concept map that describes the processes of the water cycle:Water cycle• Evaporation• Condensation• Precipitation• Water changes from liquid to gas• Water changes from gas to liquid• Water falls as rain, snow, sleet, or hail2. Construct a concept map using these terms :Conduction, radiation, convection, energy transferTransfers energy by electromagnetic waves, occurs when molecules collide, occurs through the flow of a heated substance
11.2 State of the Atmosphere.1) What is the difference between heat and temperature?2) What is the difference between Fahrenheit, Kelvin, and Celsius? What temperature does water boil for each unit? What temperature does water freeze for each type of unit?3) Define dew point and condensation.4) What is lifted condensation level?5) What happens to the density of air as you decrease in elevation? Why?6) Describe the Temperature- Density - Pressure Relationship.7) Describe why wind “blows.”8) What is humidity? Relative humidity? How does this