Sun's Activity Cycle Linked to Earth Climate
When the sun's weather is most active, it can impact Earthâ€™s climate in a way that is similar to El NiÃ±o and La NiÃ±a events, a new study suggests.
The sun experiences a roughly 11-year cycle, during which the activities on its roiling surface intensify and then dissipate. (One noted sign of a highly active period is the number of sunspots dotting the solar surface).
The total energy reaching Earth from the sun varies by only 0.1 percent across the solar cycle.
Scientists have sought for decades to link these ups and downs to Earth's natural weather and climate variations, and to distinguish their subtle effects from the larger pattern of human-caused global warming. But that link has proven difficult to find.
Scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., used computer climate models and more than a century of ocean temperature records to tease out just such a connection.
"We have fleshed out the effects of a new mechanism to understand what happens in the tropical Pacific when there is a maximum of solar activity," said study leader Gerald Meehl. "When the sun's output peaks, it has far-ranging and often subtle impacts on tropical precipitation and on weather systems around much of the world."
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