Unformatted text preview: Table 7-3, p. 192 Fig. 7-4a, p. 190 The rapid density increase in the pycnocline is mainly due to a decrease in temperature with depth in this area-- the thermocline. What is so special about water? only substance that occurs in all 3 In some regions, especially in shallow water near rivers, a pycnocline may develop in which the density increase with depth is due to vertical variations in salinity. In this case, the pycnocline is a halocline. phases as solid, liquid, and gas on Earth's surface Earth' polar molecule- dissolves more substances moleculein greater quantities than any other common liquid highest surface tension, heat conduction, and heat capacity of all common liquids Fig. 6-18b, p. 169 The Ocean's Acid-Base Balance (pH) Varies Ocean' AcidOcean's Acid-Base with Dissolved Components & Depth Carbon dioxide (CO2) combines readily with seawater to form Carbonic acid can then lose a H+ ion to become a bicarbonate carbonic acid (H2CO3). Some bicarbonate ions dissociate to form carbonate ions, which combine with calcium ions in seawater to form calcium carbonate (CaCO3), used by some organisms to form hard shells and skeletons. When their builders die, these structures may fall to the seabed as carbonate sediments, eventually to be redissolved. redissolved. As the double arrows indicate, all these reactions may move in either direction. CO2 + H2O H2CO3 H2CO3 HCO3- + H+ HCO3- + H+ CO32- + 2H+ Fig. 7-10, p. 197 ion (HCO3-), or two H+ ions to become a carbonate ion (CO32-). 1 ice salt (NaCl) Fig. 6-8, p. 161 How are Earth's ocean and atmosphere linked? Earth' Earth's Earth's Atmosphere... The interaction of ocean and atmosphere moderates surface temperatures, shapes Earth's weather and climate, and temperatures, climate, creates most of the sea's waves and currents. currents. To understand the interactions of the ocean atmosphere, we need to examine the properties of the atmosphere Different amounts of solar energy are absorbed at different latitudes. The tropics are warmer than the polar regions because of this difference. Uneven solar heating causes convection currents to form in the atmosphere. The direction of air flow in these currents is influenced by the rotation of Earth. The average composition of dry air, by volume Atmosphere volume of gases, water vapor, and airborne particles enveloping the Earth atmosphere and ocean are intertwinedintertwinedgases and water are freely exchanged wind- mass movement of air wind weather- the state of the atmosphere at a weatherspecific time and space climate- long term average of weather in climatean area Fig. 8-1, p. 203 2 Density of air... air... relationships between air temperature, water cold air more dense warm air less dense dry air more dense humid air less dense (water vapor molecules weigh less than N and O that water vapor displaced) vapor content, pressure, density less dense air rises, under less pressure, expands, conversely, compressed air warms warm air can hold more water vapor than cold air rising-expanding-cooling falling-compressing-heating and cools (cool air coming out of a tire valve) important in > weather, andunderstanding circulation, climate Fig. 8-2a, p. 204 water vapor rises, expands, cools, and condenses in to droplets (fog) http://www.vets.ucar.edu/vg/CCM3T170/index.shtml Earth's heat budget Earth' Everything, from an individual person to Earth as a whole, The Atmosphere Moves in Response to Uneven Solar Heating and Earth's Rotation Earth' emits energy. Scientists refer to this energy as radiation. As Earth absorbs incoming sunlight, it warms up. The planet must emit some of this warmth into space or increase in temperature. Two components make up the Earth's outgoing energy: heat (or thermal radiation) that the Earth's surface and atmosphere emit; and sunlight (or solar radiation) that the land, ocean, clouds and aerosols reflect back to space. The balance between incoming sunlight and outgoing energy determines the planet's temperature and, ultimately, climate. Both natural and human-induced changes affect this balance, humancalled the Earth's radiation budget. earthobservatory.nasa.gov An estimate of the heat budget for Earth. On an average day, about half of the solar energy about arriving at the upper atmosphere is absorbed at Earth's surface. Light (short-wave) energy Earth' (shortabsorbed at the surface is converted into heat. Heat leaves Earth as infrared (long-wave) Earth (longradiation. Since input equals output over long periods of time, the heat budget is balanced. Fig. 8-3, p. 205 3 Solar Heating of Earth Varies with Latitude Earth as a whole is in thermal equilibrium, but different latitudes are not. The average annual incoming solar radiation (red line) absorbed by Earth is shown along with the average annual infrared radiation (blue line) emitted by Earth. Note that polar latitudes lose more heat to space than they gain, and tropical latitudes gain more heat than they lose. Only at about 38 N and 38 S latitudes 38 38 does the amount of radiation received equal the amount lost. Since the area of heat gained (orange area) equals the area of heat lost (blue areas), Earth's total heat Earth' budget is balanced. What factors govern the global circulation of air? Uneven solar heating The Coriolis effect The ocean does not boil away near the equator or freeze solid near the poles because heat is transferred by winds and ocean currents from equatorial to polar regions. How solar energy input varies with latitude. Equal amounts of sunlight are spread over a greater surface area near the poles than in the tropics. Ice near the poles reflects much of the energy that reaches the surface there. Fig. 8-4, p. 206 The Solar Heating of Earth Also Varies with the Seasons The seasons are caused by variations in the amount of incoming solar energy as Earth makes its annual rotation around the sun on an axis tilted by 23 . During the Northern Hemisphere winter, the Southern Hemisphere is tilted toward the sun and the Northern Hemisphere receives less light and heat. During the Northern Hemisphere summer, the situation is reversed. Fig. 8-6, p. 207 A hypothetical model of Earth's air circulation if uneven solar heating were the only factor to be considered... "Convection current" Fig. 8-7, p. 208 Fig. 8-8, p. 208 4 Sea Breezes and Land Breezes Arise from Uneven Surface Heating The flow of air in coastal regions during stable weather conditions.... conditions... (a) In the afternoon, the land is warmer than the ocean surface, and the warm air rising from the land is replaced by an onshore sea breeze. (b) At night, as the land cools, the air over the ocean is now warmer than the air over the land. The ocean air rises. Air flows offshore to replace it, generating an offshore flow (a land breezes). breezes). Fig. 8-17, p. 216 5 ...
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This note was uploaded on 04/29/2008 for the course EAS 104 taught by Professor Brown during the Spring '08 term at Purdue.
- Spring '08