GEOL 1425 1st Edition Climate System1.Abundance of gasses in the atmosphere—the atmosphere contains Nitrogen, Oxygen, Argon, Water, carbon dioxide, and other greenhouse gasses. 2.Ozone in the atmosphere—ozone is a minor constituent in the atmosphere. In the lower part of the atmosphere it exists in only tiny amounts, although it is a strong enough greenhouse gas to play a significant role in the atmospheric heat budget3.Stores of fresh water in the earth’s system—continental glaciers and ice sheets cover about 10% of the land surface (about 15 mill sq. km) storing about 75% of the world’s fresh water (part of the cryosphere). Also, melting snow is the source of much of the fresh water in the hydrosphere.4.Effect of greenhouse gasses—greenhouse gasses absorb solar energy coming directly fromthe sun or reflected from Earth’s surface and reradiate it as infrared energy in all directions, including downward to the surface. The net effect is to trap heat within the atmosphere by increasing the temperature of the surface relative to the temperature at higher levels of the atmosphere. The greenhouse effect yields an overall warming of 33˚C.5.Albedo—Albedo feedback involves a rise in temperature that reduces the accumulation ofice and snow in the cryosphere, which decreases Earth’s albedo and increases the energy its surface absorbs (this is POSITIVE feedback). This contributes to the general cooling of Polar Regions.6.Records of global temperature-- For the global temperature averaged over daily and seasonal cycles to remain the same, Earth’s surface must radiate energy back into space at a rate of precisely 342 W/m2. Any less would cause the surface to heat up; any more would cause it to cool down. This equilibrium between incoming and outgoing radiant energy is achieved with the greenhouse effect. 7.Water vapor in the atmosphere—water is concentrated near Earth’s surface in highly variable amounts. Water and carbon dioxide are the principle greenhouse gasses8.Global distribution of rainfall—Topography has a direct effect on climate through its influence on atmospheric winds and circulation. Air masses that flow over large mountain ranges dump rain on the windward side, creating a rain shadow in the lee of the mountains. 9.The cooler, saltier water in the ocean—in the north Atlantic, the water cools and become more saline, and the cooler saltier water of the ocean sinks because it has become denser. This way, a subsurface cold current is created that flows southward. (thermothaline circulation)10. Periodicity in the Earth’s orbit--The shape of Earth’s orbit around the Sun changes cyclically, being more circular at some times and more elliptical at others. The degree of ellipticity of Earth’s orbit around the Sun is known as eccentricity. A nearly circular orbithas low eccentricity, and a more elliptical orbit has high eccentricity. The 100,000-year spacing of ice ages matches the times of high orbital eccentricity, when Earth received less radiation on average from the Sun.11. Presence of polar ice caps over geological time—As the polar ice caps expand, they reflect more solar energy back into space, and the surface temperatures fall further—an example of the albedo feedback.12. Presence of land masses in geologic time affecting ice ages—In most cases, the general cooling of polar regions can be well explained by rearrangements of the continents by 13. Plate tectonics, coupled with the albedo feedback and other feedbacks in the climate system.14. Location of gondwana in Permian—in the Permian-Pennsylvanian Glaciation the southern continents were joined together near the South Pole as part of the ancient continent of Gondwanaland 15. El Nino and La Nina—an anomalous warming of the eastern Pacific Ocean that occurs every 3 to 7 years and lasts for a year or so. Peruvian fishermen call such an event El Niño. El Niño events can be disastrous for local ecosystems, which depend on upwelling of cold water for their nutrient supply. La Nina is the Southern ocean cooling.Hydrologic Cycle1. World’s major rivers—although the total amount of water in rivers and lakes is relatively small, these reservoirs are important to human populations because they contain fresh water. A large river may carry great amounts of water from an area with high rainfall to an area with low rainfall. The Colorado River, for example, begins in an area of moderate rainfall in Colorado and then carries its water through arid western Arizona and southernCalifornia. 70 major rivers carry half of the world’s runoff, and the Amazon River of South America carries almost half of that. The Amazon carries about 10 times more water than the Mississippi, the largest river of North America. River: Water flow (m3/s)Amazon, South America 175,000La Plata, South America 79,300Congo, Africa 39,600Yangtze, Asia 21,800Brahmaputra, Asia 19,800Ganges, Asia 18,700Mississippi, North America 17,5002. Monsoons—in some parts of the world, seasons of heavy rain, called monsoons, alternate with long dry seasons during which water supplies shrink, the ground dries out, and vegetation shrivels.3. Vadose zones—at shallow depths, the material is unsaturated—the pores contain some air and are not completely filled with water. This level is called the UNSATURATED ZONE (often termed the VADOSE ZONE). Underneath the vadose zone is the saturated zone. 4. Intergranular porosity—the space between grains, and one of the three types of pores. It depends on the size and shape of the grains that make up soils and siliciclastic sedimentary rocks and on how they are packed together. The more loosely packed the grains, the greater the pore space between them. Minerals that cement grains reduce intergranular porosity. The smaller the particles and the more they vary in shape, the more tightly they fit together. 5. Runoff in areas of low precipitation—in areas of low precipitation—such as Southern California, Arizona, and New Mexico—only a small fraction of precipitation ends up as runoff.6. Porosity of rock types—there are three types: 1. the space between grains (intergranularporosity), 2. The space in fractures (fracture porosity), and 3. The space created by dissolution (vuggy porosity)7. Permeability in rocks—the capacity of a solid to allow fluids to pass through it is its permeability. Generally, permeability increases as porosity increases. A rock with high porosity