GEOG 1710 1st Edition Lecture 2 Outline of Last Lecture I Characteristics of Geography II Location and Place III Sensors IV Characteristics of Earth Systems V Positive Feedback and Negative Feedback Outline of Current Lecture I Planetesimal Hypothesis II The Sun and Radiation III Atmosphere Current Lecture Planetesimal Hypothesis also called dust cloud or hebula hypothesis 4 6 Billion years ago A spinning cloud of gas contracts due to gravity then proto sun forms and cloud flattens into disk Dust particles fall out and settle on disk Dust accumulates to form small planetesimals and collide Large planets capture small ones The sun is the engine that powers the Earth systems The sun is the major source of electromagnetic radiation So does microwaves phones etc Classify radiation by wavelength frequency These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Wavelength frequency are either long waves and short waves The atmosphere protects us from harmful high radiation Incoming energy from sun the sun is mostly shortwave radiation Earth absorbs radiation and sends it back as long wave radiation Atmosphere traps a lot of radiation on its way out to space Greenhouse Effect atmospheric gases allow shortwave radiation to pass through atmospheric gases allow shortwave radiation to pass through atmospheric but then absorb long wave radiation as it travels back from Earth to space The Greenhouse Effect keeps the Earth at temperature at which people can survive Insolation Incoming Solar Radiation Some areas receive more solar radiation than others Earth is a sphere Causes atmospheric ocean circulation Earth s relation to the sun changes Eccentricity Oval high eccentricity Circular low eccentricity Obliquity the tilt of Earth changes from 24 degrees to 22 degrees Atmosphere Thin layer of gases that surround the Earth Air atmospheric pressure weigh on us the further from Earth the less molecules that are pulled down by gravity weight of the air above you As you increase in altitude the air pressure goes down Atmospheric Profile Three ways to divide up the atmosphere 1 Temperature a Troposphere zone of weather supports life higher the atmosphere the lower the temperature lapse rate amount of temperature decreases with every amount increased in altitude Decreases 3 5 degrees F 1000 ft has a tropopause b Stratosphere zone of planes low turbulence low drag few air molecules less icing gets warmer higher the altitude the higher the temperature good ozone occurs here and absorbs UV radiation c Mesosphere zone of cool ice clouds higher the altitude the lower the temperature coldest portion of the atmosphere d Thermosphere zone of heat the higher the altitude the higher the temperature few molecules but it receives a lot of energy from the sun 2 Function a Protection b Ionosphere absorbs cosmic rays gamma rays x rays some UV c Ozonosphere good ozone in the stratosphere absorbs most of the harmful UV rays 3 Composition a Nitrogen is number one 78 oxygen is 20 9 b Nitrogen N2 is essential to life like DNA and proteins c Oxygen O2 is a by product of photosynthesis combines easily with others d Carbon Dioxide CO2 by product of respiration opposite of photosynthesis radiatively active e Methane CH4 is a major component of natural gas radiatively active 20 times more effective per molecule than CO2 f Nitrous Oxide N2O is laughing gas radiatively active 310 times more effective per molecule than CO2 g Ozone O3 good ozone is in the stratosphere bad ozone is in troposphere air we breathe radiatively active Tropospheric bad ozone Combusted fossil fuels plus sunlight bad ozone
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