The elevation angle used interchangeably with altitude angle is the angular height of the sun in the sky measured from the horizontal. Confusingly, both altitude and elevation are also used to describe the height in meters above sea level. The elevation angle varies throughout the day. It also depends on the latitude of a particular location and the day of the year. An important parameter in the design of photovoltaic systems is the maximum elevation angle, that is, the maximum height of the sun in the sky at a particular time of year.
This maximum elevation angle occurs at solar noon and depends on the latitude and declination angle as shown in the figure below. From the previous figure, a formula for the elevation angle at solar noon can be determined according to the formula:.
It means the sun at solar noon is coming from the south as is typical the northern hemisphere. If your latitude is 44 degrees north, the solar altitude at solar noon during an equinox will be 90 minus 44, or 46 degrees.
During the summer solstice, the solar altitude at solar noon will be During the winter solstice, the solar altitude at solar noon will be The measurements of zenith and azimuth are closely related to the measurement of solar altitude.
The solar zenith angle of the sun is relative to the zenith, or directly overhead. This is the complement of solar altitude. Hence, if the solar altitude is 46 degrees, the solar zenith angle will be 44 degrees. Azimuth, on the other hand, measures the sun's angle relative to north, in the eastward direction. If the sun is due north in the sky, the azimuth will be zero.
If the sun is due east in the sky, the azimuth angle will be 90 degrees. Solar altitude, zenith and azimuth all change throughout the day and year. Serm Murmson is a writer, thinker, musician and many other things.
He has a bachelor's degree in anthropology from the University of Chicago. His concerns include such things as categories, language, descriptions, representation, criticism and labor. He has been writing professionally since Why Are Days Longer and Shorter? Sun Intensity vs. How Many Hours of Daylight in Summer? Calendar Year vs. Earth Orbit. How to Calculate The Sun's Altitude. What Are the Causes of the 4 Seasons on Earth?
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