Tuesday, June 19, 2012

New paper finds significant increase in solar UV radiation over past 14 years

A new paper published in Theoretical and Applied Climatology finds that solar UV radiation at an observatory in Austria has significantly increased at a rate of up to 14% per decade from 1997-2011. The paper notes ozone "cannot explain these significant increases" and attributes the change to decreases in cloud cover and other aerosols. Solar UV is the most energetic portion of the solar spectrum and was recently found to vary significantly both within and between solar cycles. The IPCC dismisses the role of the Sun on climate by only considering small changes in total solar irradiance, ignoring large changes in solar UV (which is capable of penetrating the ocean surface 100 meters to cause heating - unlike IR from 'greenhouse gases'), and by ignoring amplifying effects on solar activity via clouds and ozone

2012, DOI: 10.1007/s00704-012-0684-0


High-quality long-term records of spectral UV irradiance from the Network for the Detection of Atmospheric Composition Change-affiliated Bentham spectroradiometer at the high-mountain site Hoher Sonnblick (47.05° N, 12.95° E, 3,106 m above sea level) from the period 1997–2011 have been investigated for the existence of trends. Throughout the year, significant upward trends are found at wavelengths of 315 nm and longer. The magnitudes at 315 nm range from +9.3 ± 4.5 %/dec at 45° solar zenith angle (SZA) to +14.2 ± 3.7 %/dec at SZA 65° for all-sky conditions. The trend estimates at 305 nm are considerably smaller and less significant, yielding between +5.1 ± 6.5 and +7.9 ± 7.3 %/dec, depending on SZA. Seasonally, the largest trends are found during winter and spring. Total ozone has significantly increased by year-round +1.9 ± 1.3 %/dec since 1997 and therefore cannot explain these significant increases. They are rather attributed to decreases in total cloud cover and aerosol optical depth.

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