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Unformatted text preview: Chapter 14- Atmosphere- Nitrogen and oxygen make up 99% of dry air. No oxygen present 4 billion years ago. Oxygen accumulates in atmosphere around 2 billion years ago. - Life came before free oxygen in Earths atmosphere. Atmospheric gases: nitrogen, oxygen, carbon dioxide, methane, argon, nitrous oxide, ozone and air particles (aerosols). lower boundary of the atmosphere touches Earths surface; its upper boundary is a gradational transition into space. Motion of the air in the atmosphere is related to transfer of thermal energy. 4 levels: lowest (troposphere, stratosphere, mesosphere, thermosphere). As you go up, density of the air decreases. TEMP- Energy of the atoms is known as kinetic energy. Heat: total KE of all atoms in a substance. More atoms = more heat. Temp: Average KE of all atoms in a substance. Few atoms w/rapid motion=more heat than many atoms with slower motion. TROPOSHERE- lowest level; decrease in temp w/altitude; contains weather system; air pollutions and bulk of air and aerosols; has great air density. STRATOSPHERE- increase in temp w/altitude; 20% of atmospheres air; max temp of 0F; contains ozone. MESOSPHERE- lower air temp; min temp -139F; temp lowers with altitude; fewer ozone, oxygen and nitrogen atoms; most near earth objects burn up here. THERMOSPHERE- blocks most radiation; higher temps (1,830F); auroras occur here; no real boundary. AIR PRESSURE- As air rises, it expands and pressure decreases, as pressure decreases so does the temp. Atmospheric pressure-pressure exerted by the weight of an overlying column of air . Air density- Determined by measuring the mass of atoms and molecules of N, O, and other gases. Air contracts when it cools = high air pressure; Warm air= low air pressure. ; Air pressure decreases rapidly at low altitudes with a high air density. ; Compressed air = warmer, expanding air= cooler. These changes in temperature are called adiabatic changes because they occur without any loss or gain of energy to or from the surrounding air. Chapter 15- Weather-the state of the atmosphere at a given time and place. Locations of air masses. AIR MASSES- Large volumes of air that have uniform characteristics. An air mass is identified by the temperature (warm versus cold) and moisture content (wet versus dry) of the region where it formed.cA=continental Arctic/Antarctic; forms at high latitudes around the poles above permanently snow covered ground. Characterized by extremely cold, dry air that may sweep south across Canada and produce days of below-freezing temperatures over much of the central and eastern US during winter; cP=continental polar forms over the northernmost portions of NAcT= continental tropical; mP maritime polar; mT maritime tropical. - Air masses can gain or lose heat and/or moisture as they move from one location to another. ; Principally modified by temperature of the underlying surface, and topography of the underlying surface. EX- air heated by warmer land surface will begin to rise. I t is unstable and surface, and topography of the underlying surface....
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This note was uploaded on 04/02/2008 for the course NATS 104 taught by Professor Lewis during the Spring '08 term at University of Arizona- Tucson.
- Spring '08