Energy tranfers within the atmosphere
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Introduction
Energy transfers in the atmosphere The source of energy for our planet is the sun. The sun's energy moves through space, and then through the earth's atmosphere and then finally reaches the earth's surface. This energy is then absorbed by the earth's surface and is then re-radiated as heat energy. There are three ways that heat energy is transferred through the atmosphere, radiation, conduction and convection. Conduction happens near the ground as heat energy is passed on through the movement of heat particles. All heat energy travels from a warmer region to a cold region, therefore the rate of conduction depends on factors such as temperature, surface area and the given levels of conductivity for various substances. The conduction of heat energy through the atmosphere is intensified by the amount of heat energy, which is radiated by the sun to be absorbed by the earth's surface. The transaction of heat energy from the sun to the earth is known as radiation. This is how the earth receives the heat energy emitted from the sun. This radiant heat energy is also absorbed by the earth's surface, this is what provides us with an average surface temperature of 14/15 degrees C. ...read more.
Middle
2. Light coloured ice reflects the suns energy back efficiently. 3. The altitude of ice of the melting ice is reduced so it becomes harder for new ice to form. The planet's albedo is a key climate variable in determining the radiant heat energy input to the planet combined with the solar constant. The planets annual average albedo is 0.30 (30%). The albedo varies according to geographical regions and times of year. A table showing the percentage of reflected solar radiation. Albedo effect Earth 31% Fresh Snow 75-95% Melting Snow 40-60% Thick Cloud 60-90% Thin Cloud 30-50% Ploughed Field 5-20% Grass 10-30% Deciduous Forest 15-18% Water 6-10% Deserts 25-35% Coniferous Forest 9-15% Urban Areas 15% Tropical Forest 7-15% The income of the earth's solar radiation is from the sun. The energy that reaches us from the sun is 148,800,000 km away providing us with an average surface temperature of 14 degrees C. The earth is also reflecting and re-radiating the same amount of solar radiation that it is receiving. Incoming solar radiation is absorbed by the Earth's surface, clouds, gases, the atmosphere and molecules in the atmosphere. ...read more.
Conclusion
The temperature of an area depends on the strength of the sun's heat and light penetrating its surface, which is determined by the angle at which the suns energy hits the earth. The earth's temperature is hotter at the equator and colder at the poles because of the difference in the angle of the solar radiations penetration, due to the angle of the earth's tilt which causes seasonal variations. During the earth's movement around the sun the earth's axis of rotation does not move, consequently the northern hemisphere points towards the sun during summer periods where as it points away during the winter months. This is what causes seasons and for both the northern hemisphere and the southern hemisphere this has a significant impact on the weather experienced. The sun's rays hit the equator at a direct angle where convection influences the intensity of the heat radiation experienced causing tropical climates This graph shows the temperature variations through out the year with the northern hemisphere opposing the southern. Both Johannesburg and Punta Arenas are located in the southern hemisphere hence the temperature differences compared to those locations located in the northern hemisphere i.e. Los Angeles and Liverpool. Singapore located in Asia has relatively constant yearly temperature as it is situated towards the equator on the east. ...read more.
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