Ch 9 Atmosphere 9 1 Energy force is a measure of energy that is measure by how much the force displaces something work is done to an object when force is applied to it and it moves a given distance work force x distance power energy time Types of Energy potential energy stored energy ex water held behind dam kinetic energy energy in motion water flowing from dam it loses potential energy and become kinetic heat energy energy of motion with atoms and molecules heat itself could be kinetic energy sensible heat heat that may be sensed or felt latent heat heat that is used for a substance change ie water to vapor Heat Transfer conduction heat transferred by interaction flows from one substance to another through touch example when you touch a hot surface least important kind convection transfer of heat by mass movement of fluid the pan example in class the mantle in volved in circulation of air away from equator radiation wave like energy that comes out of anything that possessed heat Earth s Energy Balance Electromagnetic Energy most of energy emitted from sun wavelength distance between the tops of two successive waves difference in wavelength is how we classify types of light energy ie x rays gamma rays etc Energy Behavior lot of ares light is the only wavelength we can see and is very small portion of wavelengths when sun s energy reaches earth it is either reflected transmitted or separated around a reflection is how solar energy returns to space transmitted energy happens more often on clear days and directly hits earth The Atmosphere atmosphere gaseous envelope that surrounds earth Composition of the Atmoshpere mainly nitrogen and oxygen humidity amount of water vapor in the atmoshpere function of heat because hot air has the capacity to hold water relative humidity ratio of water in air compared to amount of water that could be in air relative humidity is constantly changing water is constantly being exchanged from atmosphere to earth Structure of Atmosphere 4 layers one of which troposphere lowest layer not even highest mountains exceed tropo sphere rapid upward decrease in temperature that results from decreasing air pressure with in creasing altitude most clouds are in troposphere most water vapor is in troposhpere Weather Process Atmospheric Pressure and Circulation atmospheric pressure is the weight of the air above any given area greater at sea level than on a mountain top air temperature effects pressure b c cold air is denser than warm air solar heating and water evaporation near equator have a high humidity low density of heated air creates low air pressure and convects air upward into atmos air cools as it rises which increases relative humidity which is why tropics are so rainy the air is now dry b c it rained and that air travels to 30 degrees and then drops tendency of a particle of air to remain where it is or change it s position is the atmo phere Unstable Air spheric stability air is unstable if particles rise until they reach air of similar tempature atmosphere can become unstable when warm moist air is overlain by dry cold air Fronts fronts boundary between cooler and warmer air cold front is when cool air is moving into warm air and vice versa either way warm air is always lifted by colder air while cold air advances hot air is driven up which creates clouds in warm fronts the clouds are gentler and more spread out stationary front little movement between fronts occluded front when cold air overtakes another cooler air mass and warm air is wedged above the frontal boundary Hazardous Weather Thunderstorms atmospheric conditions necessary for thunderstorm occur closer to equator more often but virtually all areas experience them warm humid air must be available in the lower atmosphere to feed clouds and precipita tion and provide energy to the storm as it develops a steep vertical temperature gradient must exist in the environment such that the rising air is warmer than the air through which it is moving this gradient places colder air over warmer moist air an updraft must force moist air up to colder levels of the atmosphere these conditions are common at cold fronts thunderstorms occur as warm air is forced upward and cummulus clouds form if moisture supply and updraft continues humidty increases and cloud size increases cumulus cloud becomes a cumulonimbus cloud and continues to gorw which releases la tent heat into surrounding air mature stage downdraft and condensation begin to leave cloud cloud continues to grow until it reaches limit of tropopause final dissipative stage upward supply of moist air is blocked by downdrafts some of falling precipitation evaporates which further cools down draft and limits updraft this deprives thunderstorm of moisture and it weakens Severe Thunderstorms wind 58 mph severe thundertorm has vertical wind shear which is produced by an upward increase in the velocity or change in the horizontal direction of wind greater the vertical wind shear the greater the the thunderstorm types of severe thunderstorms mesoscale convective systems roughly circular clusters of storm cells the downdraft of one cell leads to the formation of another downdraft of storms can come together to form outflow boundaries curved lines of thunderstorms that may travel long distance squall lines linear belts of storm cells commonly develop parallel to cold fronts downdrafts on back of storm often shift forward as gust fronts of cold air squall lines can form in drylines which is like a front but the fronts differ in hu midity rather than temp super cell thunderstorms large cell with single updraft do a lot of damage can produce straight line windstorms or derechos which have tornado strength winds starts as a ice pellet gets a coat of liquid ice water in lower part of storm and that coating freezes when an updraft carries the pellet back up this cycle can repeat many times to get bigger and bigger Hail Tornadoes spinning air that extends downward from the clouds to reach the ground funnels that havent touched the ground are called funnel clouds tornados form where there are large differences in atmospheric pressures in small areas organizational stage vertical wind shear causes rotation to develop within the thunder storm updraft from the cold front and upwelling due to latent heat cause the wind tun nel to go vertical major updrafts lower a portion of the cumulonimbus cloud to form a wall cloud the wall cloud begins to rotate and if dust or debris