Solar Radiation and the Earth's Energy Balance. Take away ideas and understandings: Solar energy and gravitational energy are the fundamental sources of. Earth's climate system. In the ideal case (referred. This "give and take" of energy leads to a state of equilibrium. The energy radiated. Maximum energy is radiated at a wavelength. The total (integral over all wavelengths) energy. The energy flux radiating from a point source falls. This is why light dims fast. Using these fundamental laws and knowing the Sun's. Columbia Law School shapes the legal profession’s future leaders. We prepare our students for professional roles in a broad range of areas, including academia. ©2017 Columbia University | 420 W. 118th Street, MC 3308, New York, NY 10027 | 2 | [email protected]. Columbia University Video Lectures, Online Course videos, Columbia University Online Classes, free Online Columbia University Lectures, Online Education courses. Graduate School of Arts and Sciences Teaching Center 302 Philosophy Hall • 212-854-1066 • [email protected] The Do’s and Don’t’s of Effective Lectures. LL.M. Program. A Columbia Law School education prepares students for leadership roles—in academia, the judiciary, business and corporate practice, public service. President Bollinger recently announced that Columbia University along with many other academic institutions (sixteen, including all Ivy League universities) filed an. This is the temperature. The Earth and other. The ratio between the reflected and the incoming energies. Inaugurated in 1971 and sponsored by the Offices of the President and Provost, the University Lecture is a semiannual address given by an outstanding member of the. The Columbia University MFA Writing Program is highly regarded for its rigorous approach to literary instruction and for its faculty of acclaimed writers and editors. St. Paul’s Chapel, with its wonderful acoustics, is a landmark treasure of Columbia University. One of the finest architectural spaces on campus, it is an ideal. Because of its spherical shape incoming. At each instant. only the sun lights only. The total daily radiation. Thus the Earth's surface should. However, …The. Earth's axis of rotation tilts at a 2. This is the reason for the seasons. During. solstice, the pole pointing to the sun and the surrounding area receive. This has the potential for making the poles. Polar Regions. Introduction. In the narrow sense of the word, Climate is the average or typical state. Its description. includes the average of such variables as temperature, humidity, windiness. In the broadest sense however. Earth's habitable environment consisting of the. The atmosphere, the fast responding medium which surrounds us and immediately. The hydrosphere, including the oceans and all other reservoirs of water. CO2, and particles, such as. The land masses, which affect the flow of atmosphere and oceans through. The cryosphere, or the ice component of the climate system, whether. Earth. radiation balance and in determining the properties of the deep ocean. The biota - all forms of life - that through respiration and other chemical. In our generation climate is receiving unprecedented attention due to the. Earth during the past couple hundred years. These changes could well affect our health, comfort levels, and ability to grow. This course introduces the climate system and the processes that determine. Our goal is to explain the properties. The course will also provide a basis for further, more advanced study of. The Climate. System course is mainly concerned with the properties of atmosphere and hydrosphere. Attention to the solid and. Solid Earth and Life are dealt with in much more details in two separate. EES umbrella. Within the climate system the atmosphere plays the role of the efficient. The atmosphere is capable of quickly moving and distributing. The atmosphere directly affects life. Earth by supplying the gases for the respiration of vegetation and animals. The atmosphere also shelters life on Earth from the extreme. The oceans are. most important because of their tremendous heat storage potential and their. The composition and motion. The exchange of gases and heat between oceans and atmosphere determines the. We begin this course in a study of solar radiation, the primary energy source for Earth and. We examine the properties of the Sun. Sun to the Earth. We then study in detail the transformation of this solar. Earth and gain first appreciation on how this energy shapes the. Earth's climate. Review: What is energy? The Earth Radiation Budget Part 1: Energy from the Sun. The energy that drives the climate system comes from the Sun. When the Sun's energy reaches the Earth it is partially absorbed in different. The absorbed energy is converted back. Earth to warm up and makes it habitable. Solar radiation absorption is uneven in both space and time and this gives. To understand. the complex patterns of Earth's radiative heating we begin by exploring the. Earth and the Sun throughout the year, learn about the. Earth as a whole. We examine the relationship between solar radiation and the Earth's temperature. We complement this lecture by a set of two laboratory. Earth radiation budget as they are revealed through. Earth. The Sun and its energy. The Sun is the star located at the center of our planetary system. It is. composed mainly of hydrogen and helium. In the Sun's interior, a thermonuclear. The energy created by the fusion reaction is converted. Sun to levels that are about twenty times larger that of the Earth's. The solar heat energy travels through space in the form of electromagnetic. Review: electromagnetic waves. Solar radiation occurs over a wide range of wavelengths. However, the energy of solar radiation is not divided evenly over all wavelengths. Figure. 1 shows, is rather sharply centered on the wavelength band of 0. As can be seen from Figure. IR, 0. 7- 1. 00 μm). The physics of radiative heat transfer. Before proceeding to investigate the effect of solar radiation on Earth. In particular we should understand the following. The radiative heat transfer process is independent of the presence of. It can move heat even through empty space. All bodies emit radiation and the wavelength (or frequency) and. The energy flux drops as the square of distance from the. Radiation goes through a transformation when it encounters other objects. That transformation depends on the physical properties. To read more about these points go to radiative. Radiation transfer from Sun to Earth. Properties of Solar radiation: The Sun is located. Solar System, at a distance of about 1. Earth. With a surface temperature of 5. K (degrees Kelvin = degrees C +. Sun is approximately 6. W/m. 2 (Do you know what. Check the link. to radiative heat transfer.) This radiative flux maximizes at a wavelength. Solar radiation on Earth: As the Sun's energy spreads. However the energy flux drops monotonically. Sun. Thus, when the radiation reaches. Earth's atmosphere, several hundred kilometers over. W/m. 2 (Can. you calculate this number from the flux at the surface of the Sun and the. Earth? Can you figure out the flux. Pluto, which is 3. Earth?). Effect of orbit's shape: The radiation at. Earth spins around the Sun. This is because the Earth's orbit is. Sun located in one of the foci of. The Earth is closer to the sun at one time of year (a point. The time- of- year when. Earth is at perihelion moves continuously around the calendar year. At present perihelion occurs in the middle. Northern. Hemisphere winter. The annual average radiative solar flux at the top of. Earth's atmosphere (=1. W/m. 2) is sometimes referred to. Solar Constant because it has changed by no more. Earth (last few hundred. There are however important variations in this flux over longer. Earth glaciation cycles are attributed. Effect of Earth's spherical shape: If the Earth. However, the Earth is a sphere and aside from the. Figure. 5). The tilt of the Earth's axis and the seasons: If. Earth was perpendicular to the plane of its orbit (and the direction. However, as seen in Figure. Earth axis tilts at an angle of 2. Once a year, on the Summer Solstice (on or about. June), the North Pole points directly towards the Sun and the. South Pole is entirely hidden from the incoming radiation. Half a year from. Winter Solstice (on or about the 2. December) the North. Pole points away from the Sun and does not receive any sunlight while the. South Pole receives 2. During Solstices, incoming. Earth surface on either the latitude. Cancer or the latitude of Capricorn,2. Northern Hemisphere, respectively. During the spring and fall (on the Equinox. March and 2. 3rd of September) the Earth's axis tilts in. Sun and both Polar Regions get the same amount of light. At that time. the radiation is largest at the true equator. Averaged over a full 2. Figure. 7. Note that the figure combines the effect of the change in incidence. At the poles, during solstice, the earth is either exposed. Sun throughout the entire day. This is why the poles get no incoming radiation. The Earth Radiation Budget Part 2: Energy from Earth and Earth's temperature. The Earth's albedo. The Earth's surface reflects (that is, returns the radiation back to space. This is what. makes the part of the Earth lit by the. The most obvious aspect of Figure 8 is the brightness. Earth's cloud cover. A significant part of the Earth's reflectivity. Earth's climate). In climate texts the reflectivity of a planet is. The albedo of Earth depends on the geographical. Figure 7 which has higher albedo, the land or the ocean?). On the average however, the Earth's albedo is about 0. This fraction of incoming radiation is reflected back into space. The other. 0. 7 part of the incoming solar radiation is absorbed by our planet. Effective temperature. By absorbing the incoming solar radiation, the Earth warms up, like a black. If the Earth. would have had no atmosphere or ocean, as. All heated objects must emit electromagnetic radiation. This radiation is. As long as the incoming radiative. This in turn will result in. Stefan- Boltzman. At some point the object will emit as much radiation as the amount incoming. Using what we have learned about radiative heat transfer and some geometric. Here is how we do that. Sun: First let us denote the solar radiative flux at the top of the planets atmosphere. So (for solar constant) and the albedo of. Then let us figure out the total amount of radiation absorbed by the planet. To overcome the difficulty posed by the fact that the planets are spherical. If the planet's radius. R the area of that disk is πR2. Thus: heat absorbed by planet = (1 - a) πR2. So. The total heat radiated from the planet is equal to the energy flux implied. Te(from the Stefan- Boltzman law) times the entire surface. R2) σT4. In radiative balance we thus have. R2 ) σTe. 4 =. (1 - a) πR2. So. Solving this equation for temperature we obtain. Te = [(1- Aa)So / 4σ] 1/4. We have added a subscript e to the temperature to emphasize. It is referred to as the effective temperature of. According to this calculation, the effective temperature of Earth. K (or - 1. 8 °C). With this temperature the Earth radiation will be. IR) radiation. Because of the spectral properties of the Sun and Earth radiation we tend. The greenhouse effect. The effective temperature of Earth is much lower than what we experience. Averaged over all seasons and the entire Earth, the surface temperature. K (or 1. 5°C). This difference. This effect is known as.
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