Tiny Sun Activity Changes Affect Earth's Climate | Solar Sunspot Cycle | Space.com - 0 views
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Even small changes in solar activity can impact Earth's climate in significant and surprisingly complex ways, researchers say.
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The sun is a constant star when compared with many others in the galaxy
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ome stars pulsate dramatically, varying wildly in size and brightness and even exploding
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In comparison, the sun varies in the amount of light it emits by only 0.1 percent over the course of a relatively stable 11-year-long pattern known as the solar cycle.
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"the light reaching the top of the Earth's atmosphere provides about 2,500 times as much energy as the total of all other sources combined,"
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even 0.1 percent of the amount of light the sun emits exceeds all other energy sources the Earth's atmosphere sees combined, such as the radioactivity naturally emitted from Earth's core,
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Many of the ways the scientists proposed these fluctuations in solar activity could influence Earth were complicated in nature.
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, solar energetic particles and cosmic rays could reduce ozone levels in the stratosphere
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in turn alters the behavior of the atmosphere below it, perhaps even pushing storms on the surface off cours
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"In the lower stratosphere, the presence of ozone causes a local warming because of the breakup of ozone molecules by ultraviolet light,
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When the ozone is removed, "the stratosphere there becomes cooler, increasing the temperature contrast between the tropics and the polar region
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contrast in temperatures in the stratosphere and the upper troposphere leads to instabilities in the atmospheric flow west to east.
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feed the strength of jet streams, ultimately altering flows in the upper troposphere, the layer of atmosphere closest to Earth's surface.
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alter the distribution of storms over the middle latitudes
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the sun might have a role to play in this kind of process. I would have to say this would be a very difficult mechanism to prove in climate models
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climate scientist Gerald Meehl at the National Center for Atmospheric Research and his colleagues suggest that solar variability is leaving a definite imprint on climate, especially in the Pacific Ocean.
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When researchers look at sea surface temperature data during sunspot peak years, the tropical Pacific showed a pattern very much like that expected with La NiƱa,
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cyclical cooling of the Pacific Ocean that regularly affects climate worldwide, with sunspot peak years leading to a cooling of almost 1 degree Celsius (1.8 degrees Fahrenheit) in the equatorial eastern Pacific
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peaks in the sunspot cycle were linked with increased precipitation in a number of areas across the globe, as well as above-normal sea-level pressure in the mid-latitude North and South Pacific.
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Scientists have also often speculated whether the Maunder Minimum, a 70-year dearth of sunspots in the late 17th to early 18th century, was linked with the coldest part of the Little Ice Age, during which Europe and North America experienced bitterly cold winter
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This regional cooling might be linked with a drop in the sun's extreme ultraviolet radiation.
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t, the sun could currently be on the cusp of a miniature version of the Maunder Minimum, since the current solar cycle is the weakest in more than 50 years.
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Although the sun is the main source of heat for Earth, the researchers note that solar variability may have more of a regional effect than a global one
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While the sun is by far the dominant energy source powering our climate system, do not assume that it is causing much of recent climate changes. It's pretty stabl
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Ancient signals of climate such as tree rings and ice cores might also help shed light on the link between the sun and climate
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Since variations in Earth's magnetic field and atmospheric circulation might disrupt this evidence on Earth,
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a better long-term record of solar radiation might lie in the rocks and sediments of the moon or Mar