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( Sunlight)
Sunlight, in the broad sense, is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon. This is usually during the hours known as day. Near the poles in summer, sunlight also occurs during the hours known as night and in the winter at the poles sunlight may not occur at any time. When the direct radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and heat. Radiant heat directly produced by the radiation of the sun is different from the increase in atmospheric temperature due to the radiative heating of the atmosphere by the sun's radiation. Sunlight may be recorded using a sunshine recorder, pyranometer or pyrheliometer. The World Meteorological Organization defines sunshine as direct irradiance from the Sun measured on the ground of at least 120 W·m-2. Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared, visible, and ultra-violet light. Bright sunlight provides luminance of approximately 100,000 candela per square meter at the Earth's surface. Sunlight is a key factor in the process of photosynthesis. To calculate the amount of sunlight reaching the ground, both the elliptical orbit of the earth and the earth's atmosphere have to be taken into account. The extraterrestrial solar illuminance (Eext), corrected for the elliptical orbit by using the day number of the year, known as the Julian date (Jd), is Eext=Esc(1 + 0.034 * cos(2pi(Jd - 2) / 365))
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Sunlight Subcategories
Sunlight Articles
New Technology to keep your Green Thumb Happy by Nathan Mathew
Once Mirabel Osler had said, that there is no other preoccupation as fulfilling as gardening as, if you ever creep up behind someone at this work, you will always find him smiling. Indeed time and again it has been seen that, out of all the hobbies k...
Fighting Fatigue by Sandra Powers
Fighting Fatigue by Sandy Powers
My daughter was complaining how tired she is. Kay is in her middle thirties and had just started a new job in Human Resources.
“I am so tired, “she sighed. “I’m dragging through the day. I’m...
Fitness Tip: Sunlight, Fresh Air and Exercise by Ismael Tabije
All energy surely emanates from the sun and without sunlight healthy conditions are impossible. Therefore, if you would want to prolong your life, stay in the sunlight as much as possible. If you wish to be healthy, breathe deeply fresh air charged w...
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