AOSC200 1 27 Weather what is going on in the atmosphere at a specific time and place pressure temp wind speed wind direction Climate set of conditions that prevails in a region over at least 30 yr period precipitation temp wind speed wind direction Temperature anomaly change in temperature relative to an average value Little ice age change by 1 2 degrees Ice Age change by 5 degrees Numbers on a weather map station readings temp dew point wind speed wind direction 1 29 Atmospheric composition Front boundary between two differing air masses Cold front cold air replacing warm air blue on map Warm front warm air replacing cold air red on map Stationary front cold front meeting warm front neither front strong enough to move the other red and blue on map Occlucded front cold front overtakes a warm front purple on map Troposphere temperature decreases with height the rate that temperature decreases with height is called the Lapse Rate 6 5deg C per km or 3 5deg F for every 1000ft Tropopause there s a pause in the temperature decreasing Stratosphere temperature increases with height when temperature increases with height it s called a temperature inversion warms up because of more ozone trapping infrared light Stratopause there s a pause in the temperature increase Mesosphere temperature decreases with height Mesopause there s a pause in the temperature decrease Thermosphere temperature increases in height Atmosphere puts pressure on us everyday ideal gas law pressure density x temp x constant if pressure is high density is high if temperature is high density is low Nitrogen 78 08 oxygen 20 94 argon 934 carbon dioxide 035 Water 00001 4 Carbon dioxide cycle one of the most talked about greenhouse gases some CO2 is produced naturally some CO2 produced by human activity anthropogenic once in the air some CO2 stays there goes in the ocean or goes into the land CO2 stays in the air for 200 yrs seasonal variation of CO2 concentration spring plants grow begin to absorb CO2 fall plants die stop absorbing CO2 500 million years ago CO2 was 20 times higher than today 2 3 Low pressure system like a vacuum cleaner lowest pressure strong hurricanes bring weather High pressure system like a spray can low mild winds and clear skies stagnant air can lead to bad air quality When looking at a weather maps lines that are close together pressure lines close together tight pressure gradient air moves quickly from high pressure to low pressure results in STRONG wind gusts CO2 continued CO2 cycle sources sinks volcanoes plant animal respiration plant decay burning of fossil fuels burning of plants deforestation plant photosynthesis oceans carbonates ocean critters like oysters use it to make their shells currently there are more sources than sinks as a consequence CO2 in the air is rising this rise is correlated with the rise in temperatures currently there are few ways to reduce CO2 there has been a 30 increase in acidity of the ocean since 1700 and now expect that by 2100 it will have become a 100 increase This constitutes a rate of change in ocean chemistry that is 10 times anything scientist can document over the last 50 million years Methane sources rice paddies wetlands termites gas production landfills ruminants biomass burning coal mining ocean fresh water methane hydrate methane is mainly lost by chemical reactions in the atmosphere the carbon in methane eventually becomes CO2 Aerosols really tiny any little speck of anything flying in the air dust smoke particles bacteria help form rain and snow main sources oceans salt water erosion fires volcanoes and human activity can be harmful to human health London smog Ozone absorbs UV radiation good ozone in stratosphere bad ozone in the troposphere greenhouse effect in negative way close to the surface smog Energy transfer sublimation ice vapor deposition vapor ice temperatures rise within the stratosphere because of the ozone layer Latent heat the heat required to melt or evaporate a substance EX ice in the cooler absorbs heat from the drinks result the ice melts while the drinks stay cold EX you sweat your body gives off water and it evaporates transferring that latent heat from your body when a substance freezes or condenses the latent heat is released back into the environment as water condenses to form a could all of the heat that went into evaporating the water in the 1st place is released to the air FINISHH Specific heat the amount of heat required to increase the temp of 1 gram of the substance 1degC EX water takes longer to heat and cool than dirt Conduction requires contact energy transferred from molecule to molecule air is not a good conductor it s a good insulator metals are excellent conductors very important at earth s surface heats up gets warm Convection energy transferred by movement of fluids in science air is considered a fluid surface energy transferred upward by convection hot air rises and cool air sinks lava lamps are a good example of convection rising hot air creates a convective circulation cell called a thermal thermals will eventually spread out sink and move back to the starting point creating wind Advection horizontal movement of air aka wind Rising and sinking air air that is pushed upward will cool down air that sinks will heat up Temp and Density Ideal Gas Law pressure density x temp x constant density pressure temp x constant as temp rises density falls Balloon demonstration surrounding air is denser and heavier and sinks the less dense air is pushed up by the sinking heavy air it floats Radiative heat heating due to electromagnetic radiation called radiation but is different from nuclear radiation spectrum range of values wavelength length of one wave 2 5 when air rises it cools down water vapor cools condenses latent heat helps it rise more Solar Spectrum the energy from the sun peaks at 5um the energy from the earth peaks at 10um the sun releases energy at shorter wavelengths UV visible near infrared the earth releases energy at longer wavelengths IR UV energy has no problem getting through but IR has trouble getting out Most powerful greenhouse gas is Water vapor Not CO2 we focus on CO2 because we can control that more we have more direct impact on CO2 with more CO2 temp rises more water vapor produced Greenhouse effect is good ENHANCED GREENHOUSE EFFECT is bad Positive Feedback mechanism temperature increases more water evaporated temperature gets warmer We re slowly closing the atmospheric window where energy can