Describe the three Milankovitch (orbital) cycles and how each cycle affects the

Question

Describe the three Milankovitch (orbital) cycles and how each cycle affects the amount and/or distribution of solar radiation received by the Earth. Include a discussion of how the cycles can influence the growth and retreat of ice sheets, particularly in the Northern Hemisphere. What is the critical season that determines ice sheet growth and decay? (7pts) If the tilt (= obliquity) of the Earth increases, will the summers in the Arctic (= NH polar region) become warmer or cooler (3 pts)? Explain your answer. And what about summers in the Antarctic (3 pts)? What is more important for the growth or retreat of an ice sheet of an ice sheet, winter or summer insolation at 65 degrees North? Explain why (3pts)

Explanation / Answer

Variations in the Earth's eccentricity, axial tilt, and precession comprise the three dominant cycles, collectively known as the Milankovitch Cycles for Milutin Milankovitch, the Serbian astronomer. three of them together accounts for alterations in the seasonality of solar radiation reaching the Earth's surface. The amount of increased or decreased solar radiation influence the Earth's climate system, resulting in advance and retreat of glaciers.

The first of the three Milankovitch Cycles is the Earth's eccentricity. Eccentricity means , the shape of the Earth's orbit around the Sun. The shape is alternating between more or less elliptical (0 to 5% ellipticity) on a cycle of about 100,000 years.

The more elliptical it is, climate will be more colder, thus ice sheets will grow more each year, because radiations won’t reach the surface be as high as it would reach on a less elliptical osscilation.

Axial tilt, is the inclination of the Earth's axis in relation to its plane of orbit around the Sun. Thoscycle causes earths seasonal changes,seasens will last longer or end faster. Oscillations in the degree of Earth's axial tilt occur on a cycle of 41,000 years which ranges 21.5 to 24.5 degrees. With less axial tilt the Sun's solar radiation is more evenly distributed between winter and summer causing, growth of ice sheets. Ie, due to warmer winter, more mouture is absorbed in atmosphere and when winter comes, more snow fall will occur.

The third Cycle is Earth's precession which is Earth's wobble as it spins on axis. Earth will wobble back and forth on its axis. The precession of Earth wobbles from pointing at Polaris (North Star) to pointing at the star Vega. When this shift to the axis pointing at Vega occurs, Vega would then be considered the North Star. This top-like wobble, or precession, has a periodicity of 23,000 years.

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.