THE ATMOSPHERE Structure and Temperature ATMOSPHERE CHARACTERISTICS Most

THE ATMOSPHERE Structure and Temperature

ATMOSPHERE CHARACTERISTICS • Most important measurable properties • Air Temperature • Humidity • Type of Precipitation • Amount of Precipitation • Air Pressure • Speed of Wind • Direction of Wind

WEATHER VS CLIMATE • Weather • Conditions of the atmosphere at a given time and place • The day to day changes • Climate • Observations of weather that have been collected over many years

COMPOSITION OF THE ATMOSPHERE • Wasn’t always like it is now • 4. 6 billion years ago was made of gases from volcanic eruptions • Oxygen started gathering around 2. 5 billion years ago • Continuously exchanges

MAJOR COMPONENTS OF ATMOSPHERE • Varies from time to time and place to place • 99% Nitrogen and Oxygen • . 93% Argon • . 039% CO 2

VARIABLE COMPONENTS • 1. Water Vapor • Source of all clouds and precipitation • Absorbs heat given off by Earth • Absorbs solar energy

VARIABLE COMPONENTS • 2. Dust Particles • Large particles don’t stay in the air for long • Microscopic particles travel for miles • Sea salts from breaking waves • Fine soil blown into air • Smoke and soot from fires • Pollen and other microorganisms • Ash and dust from volcanic

VARIABLE COMPONENTS • 3. Ozone (O 3) • Concentrated in layer 10 -50 km above Earth’s surface • Near earth we have O 2, but when it rises it absorbs UV radiation and splits into O • Ozone formed when single O atoms collide with O 2 atoms • Ozone layer important to us • Blocks UV rays

HUMAN INFLUENCE • Primary Pollutants • Emitted directly from identifiable source

HUMAN INFLUENCE • Secondary Pollutants • Not emitted directly in air • Form when primary pollutants mix in atmosphere • Sulfur dioxide enters atmosphere • Reacts with oxygen gas • Produces Sulfur Trioxide • Combines with water to produce acid rain

HUMAN INFLUENCE • Secondary Pollutants • Not emitted directly in air • Photochemical reactions • Nitrogen oxides absorb solar radiation • Produces irritating, toxic volatile organic compounds • Known as photochemical smog

PRESSURE CHANGES IN ATMOSPHERE • The higher you go the less air there is to push down on you

TEMPERATURE CHANGES IN ATMOSPHERE • What does this picture show us about temperature changes?

LAYERS OF THE ATMOSPHERE • 1. Troposphere • Tropopause • 2. Stratosphere • Stratopause • 3. Mesosphere • Mesopause • 4. Thermosphere

LAYERS OF THE ATMOSPHERE • 1. Troposphere • Temperature decreases with altitude • All weather occurs here • Made of 99% nitrogen, oxygen, argon and carbon dioxide • Most dense at surface of Earth

LAYERS OF THE ATMOSPHERE • 2. Stratosphere • Temperature is constant up to 20 km then increases (ozone layer) • No wind so air is calm • 19% Atmospheric gases – the rest is ozone

LAYERS OF THE ATMOSPHERE • 3. Mesosphere • Temperature decreases with height • Nitrogen and Oxygen levels are the same as troposphere • There is very little movement but still dense enough to stop meteors

LAYERS OF THE ATMOSPHERE • 4. Thermosphere • Temperatures increase because solar radiation is being absorbed • Very thin • Molecules can travel for miles before hitting one another • We can’t really describe its chemical composition because there are hardly any molecules here

LAYERS OF THE ATMOSPHERE

EARTH-SUN RELATIONSHIPS • All energy for Earth’s weather and climate comes from sun • Earth absorbs less than one twobillionth of energy given off by sun • Still several hundred thousand times more than we need • Sun doesn’t heat everywhere on Earth evenly • Unequal heating causes wind and

EARTH’S MOTIONS • Rotation • Spinning on axis • Happens every 24 hours • Revolution • Orbit around sun • Happens every year • Earth travels 113, 000 km/hr

EARTH’S ORIENTATION • Why is it colder in the winter and warmer in the summer? • Seasonal changes happen because of the tilt of the Earth’s axis • Earth is tilted at 23. 50 from perpendicular • Axis always pointed toward North Star

SUN’S APPARENT PATH • Varies with latitude and season • Angle of noon sun can vary up to 47 degrees in our location • In June when we are pointed toward the sun the rays hit us at a 73. 5 degree angle • In December when we are pointed away it hits at a 26. 5 degree angle

THE SEASONS AND LENGTH OF DAY

SECTION ONE REVIEW • Compare and contrast weather and climate. • Why do seasonal changes occur? • How much of the Earth’s atmosphere is located below 5. 6 kilometers? • How do ozone molecules form? • In which layers of the atmosphere does temperature increase with increasing height? • Explain what would happen to air temperatures in the troposphere if carbon dioxide were removed from air.

HEATING THE ATMOSPHERE • Heat and temperature are two different things • Heat is the energy transferred from one object to another because of a difference in their temperatures • Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance • If energy is added to molecules they move faster and the temperature

WAYS TO TRANSFER ENERGY • 1. Conduction • Transfer of heat through matter by molecular activity • Molecules are close to one another and when one gets excited it hits the one next to it which also gets excited • Like a metal spoon in a hot pot

WAYS TO TRANSFER ENERGY • 2. Convection • Transfer of heat by mass movement or circulation within a substance • Like a lava lamp or hot air balloon • Sun warms objects, air around those objects gets heated by conduction then warm air rises

WAYS TO TRANSFER ENERGY • 3. Radiation • Travels through vacuum of space • All objects, no matter what their temperature, emit radiant energy • Hotter objects radiate more total energy than colder objects • The hottest radiating bodies produce the shortest wavelengths • Objects that are good absorbers of radiation are good emitters too • Atmosphere doesn’t absorb all wavelengths-

WAYS TO TRANSFER ENERGY

ELECTROMAGNETIC WAVES • These waves move at 300, 000 km/second through space • Our atmosphere doesn’t slow them down too much • Waves move out from source like a pebble hitting water

ELECTROMAGNETIC WAVES RAINBOW IS ALWAYS IN SAME ORDER AS ELECTROMAGNETIC SPECTRUM DOUBLE RAINBOW IS REVERSED

WHAT HAPPENS TO RADIATION? • 1. Absorbed • Energy added and temperature increases • 2. Transmitted • Energy passes through • 3. Reflected • Energy bounces off object

WHAT HAPPENS TO RADIATION?

REFLECTION AND SCATTERING • Reflection • Wave bounces off object with same intensity that it hit object • Scattering • Wave split into large number of weaker waves

SO WHY IS THE SKY BLUE? • The air is full of small dust and gas particles • Light gets scattered in all directions • This is how light reaches underneath a shade tree • Blue has a very short wavelength compared to other colors • It gets scattered the most • Sunrise and Sunset are red/orange because of the angle we see them • They have to pass through a lot of particles • Red and orange are long wavelengths and

ABSORPTION • Water vapor and carbon dioxide are good absorbers • When they absorb energy their temperature rises • Known as Greenhouse Effect • This is actually a good thing • We’d be really cold without it • Different from Global Warming • This increase is caused or influenced by

PHOTOSYNTHESIS • Small amount of energy not absorbed and then reradiated • Chlorophyll in plants absorb this energy and use it to make their own type of energy • So the sun is the main source for all energy on Earth

SECTION 2 REVIEW • How are heat and temperature related? • What are three ways heat is transferred? • What three things happen when solar radiation strikes an object? • How are scattering and reflection different? • Dark objects tend to absorb more radiation than light-colored objects. Explain whether dark objects or light

TEMPERATURE CONTROLS • Any factor that causes temperature to vary from place to place and time to time • Latitude • Differential heating of land water • Altitude • Geographic position • Cloud cover

LAND WATER • Lands heats more rapidly but also cools off more rapidly • Cities near water have less temperature variations

LAND WATER • Northern hemisphere • 61% land • 39% water • Southern hemisphere • 19% land • 81% water

GEOGRAPHIC POSITION • Windward coast • Wind blows from ocean onto shore • Leeward coast • Wind blows from land out to ocean

GEOGRAPHIC POSITION • Mountains can get in the way • Reduces effect of windward location

ALTITUDE • Guayaquil • 12 m above sea level • Quito • 2800 m above sea level

CLOUD COVER AND ALBEDO • Albedo • Fraction of total radiation reflected by any surface • Clouds have high albedo • So does snow • During the day you want clouds to reflect sun away and keep you cool • At night you want clouds to reflect Earth’s heat back upon itself to keep you warm

CLOUD COVER AND ALBEDO

WORLD DISTRIBUTION OF TEMPERATURE • Isotherms • Connect points of equal temperature • Look at World Isotherm Map on page 493 • What effect does latitude have on temperature? • What effect does the distribution of land water have on temperature? • Estimate the latitude range for temperatures between 20 and 25 degrees Celsius in the Northern Hemisphere. • Do you expect the color of the temperature band to change near the equator for the month of January?

SECTION 3 REVIEW • What is a temperature control? • How do the heating of land water differ? • Why is it cooler on a cloudy day? What happens to the radiation from the sun on these days? • Why do some coastal cities experience a moderation of temperature from water, while others do not?