Two years after the sun peaks in its 11-year cycle, Earth's climate undergoes small El Nino-like warming effects, which have been tied to floods, droughts and other weather systems.
So concludes a new study that is one of the first to link cyclical variations in solar activity to Earth's climate.
The research, led by scientists at the National Center for Atmospheric Research (NCAR) in Colorado, is based on computer models of ocean surface temperatures recorded between 1890 and 2006.
The team then simulated how changes in solar output -- which varies only by about 0.1 percent throughout the sun's 11-year cycle -- would impact temperatures on Earth.
They discovered that solar max slightly elevates atmospheric heating, particularly over the tropical and subtropical Pacific, where sun-blocking clouds are scarce.
The extra heat leads to more evaporation, which in turn increases the amount of water vapor in upper-atmospheric winds, triggering heavier rains in the western tropical Pacific and cooler, drier conditions in the east.
The researchers found an El Nino-like warming event occurs about two years after solar max and lasts about a year.
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