B) when the noon sun angle is directly overhead at 16 degree north, what is the
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Question
B) when the noon sun angle is directly overhead at 16 degree north, what is the noon sun angle at 55 degrees south?Lab 2 LAB 2-Earth-Sun Relationships Key Ideas Revolution Plane of the ecliptic Circle of illuminatiorn Axial parallelism Subsolar point Equinox Solstice Sun angle Discussion Orbital Characteristics earth has two types of movement, daily rotation around its polar axis froem west to east, and ariations in how ts orbial path around the sun. The earth completes one revolution every 363.25 days Daring the year, variations in the orientation of the earth with respect to the sun caase v energy is distributed over the earth. One result is the earth's annual cycle of seasons The earth orbits around the sun in an elliptical path. That path is a smooth, flat plane. In other as the earth moves in its orbit anound the sun it does not bob up and down. The plane surface of earth's orbital path is called the plane of the ecliptic. The earth remains in a constant orientation with respect constant tilt of 23.5° off of perpendicular. This s plane of the ecliptic is the concept of axial parallelism, or just parallelism. The earth's axis on any day of the year is parallel Polaris, is always directly overhead at the North Pole. Seasonal changes that we experience on earth are to this plane. The earth's axis is not perpendicular to the plane of the ecliptic, but maintains the oestant oricntation of the earth's axis with respect to the to its position on any other day of the year. Parallelism explains why the North Star caused by revolution, axial tilt, and parallelism. Factors that change seasonally include sach things as temperature, the height of the noon the rising and setting sun with respect to the horizon. Seasonal Changes At any given time the sun illuminates one half of the earth. The line that divides the half in daylight from the half in darkness is called the cirele of illumination because it traces out a circular circumference of the spherical earth. Solar energy reaches our planet as parallel rays of sunlight, but because of the earth's spherical shape, on any one day there is only one latitude that will receive those parallel rays from directly (vertically) overhead. Even at that one latitude, the sum's rays will not be directly overbead at dawn, dusk, late morning, or afternoon, but only at noon. The height of the sun in the sky is always measured at its maximum for the day, which is solar noon. Even on the latitude that is receiving vertical rays of the then, the exact longitudinal point currently experiencing the 90° sun angle changes as the earth rotates through the day. That exact point is called the subsolar point. The analemma (Fig. 2.1) is a diagram that shows the latitude of the subsolar point for every day of the year. Each day, the latitude of the subsolar point changes slightly because the earth has changed its position in its orbit slightly. The subsolar shifts day by day so that during the course of the year it moves from 23.5°8 (the Tropic of Capricom) towards the equator, on to 23.S N (the Tropic of Cancer), back towards the equator, and finally returning at the end of the year back to the Tropic of Capricorn. The subsolar point only occurs between latitudes 23.5 S and 23.5 N, a range of 47° of latitude sun, GEO 121 D-G-Spring 2018
Explanation / Answer
A) On how many days a year does Brownsville, Texas, receive vertical rays of the sun at noon?
Ans. Through out the year positions of vertical Sun rays at noon over the Earth surface changes, and the range is from 23.5oN to 23.5oS, that is, from Tropic of Cancer to Tropic of Capricon. So, only thoes areas situated between 23.5oN to 23.5oS will experience vertical Sun rays.
The latitude of Brownsville, Texas is nearly 26oN. The maximum noon Sun angle of Brownsville, Texas will suffer in 21 June. At 21 June, Sun is directly overheaded at 23.5oN. And the noon Sun angle of Brownsville, Texas i this day is [90 - (26-23.5)] = 87.5o. So, Brownsville, Texas will not suffer vertical Sun rays.
B) When the noon sun angle is directly overhead at 16 degree north, what is the noon sun angle at 55 degrees south?
Ans. Two days in a year 7th May and 7th August the noon sun angle is directly overhead at 16 degree north.
The noon sun angle at 55 degrees south in those days is = 90 - (55+16) = 90 - 71 = 19o.
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