Related topics: magnetic field · earth · sun · nasa

90% of Floridians believe climate change is happening: Survey

The latest edition of Florida Atlantic University's "Florida Climate Resilience Survey," found that 90% of Floridians believe that climate change is happening. In comparison, a recent Yale University survey showed 72% of ...

Dazzling auroras fade from skies as sunspot turns away

The spectacular auroras that danced across the sky in many parts of the world over the weekend are fading, scientists said Monday, as the massive sunspot that caused them turns its ferocious gaze away from Earth.

NASA scientists gear up for solar storms at Mars

In the months ahead, two of NASA's Mars spacecraft will have an unprecedented opportunity to study how solar flares—giant explosions on the sun's surface—could affect robots and future astronauts on the Red Planet.

Luminous quasar PDS 456 explored with MUSE

Using the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) in Chile, an international team of astronomers has inspected a luminous quasar known as PDS 456. Results of the observational campaign, ...

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Solar variation

Solar variations are changes in the amount of solar radiation emitted by the Sun. There are periodic components to these variations, the principal one being the 11-year solar cycle (or sunspot cycle), as well as aperiodic fluctuations. Solar activity has been measured via satellites during recent decades and through 'proxy' variables in prior times. Climate scientists are interested in understanding what, if any, effect variations in solar activity have on the Earth. Effects on the earth caused by solar activity are called "solar forcing".

The variations in total solar irradiance remained at or below the threshold of detectability until the satellite era, although the small fraction in ultra-violet wavelengths varies by a few percent. Total solar output is now measured to vary (over the last three 11-year sunspot cycles) by approximately 0.1% or about 1.3 W/m² peak-to-trough during the 11 year sunspot cycle. The amount of solar radiation received at the outer surface of Earth's atmosphere averages 1,366 watts per square meter (W/m²). There are no direct measurements of the longer-term variation and interpretations of proxy measures of variations differ. On the low side North et al. report results suggesting ~ 0.1% variation over the last 2,000 years. Others suggest the change has been ~ 0.2% increase in solar irradiance just since the 17th century. The combination of solar variation and volcanic effects are likely to have contributed to climate change, for example during the Maunder Minimum. Apart from solar brightness variations, more subtle solar magnetic activity influences on climate from cosmic rays or the Sun's ultraviolet radiation cannot be excluded although confirmation is not at hand since physical models for such effects are still too poorly developed.

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