Sunday, August 17, 2014

The Amplified Climate Impacts of Solar Radiation

Climate models dismiss the role of the Sun in climate change by only considering the tiny 0.1% variations in Total Solar Irradiance [TSI] over solar cycles, while ignoring large changes in the solar spectrum such as variations in UV forcing of up to 100% over solar cycles. High-energy solar UV penetrates the ocean to the greatest depths in comparison to other solar wavelengths, heating the oceans more efficiently than other portions of the solar spectrum. Solar UV also affects production of the radiatively-active gas ozone, which also affects surface temperatures. 

Climate models also ignore other potential solar amplification mechanisms via solar energetic particles [SEPs], galactic cosmic rays [GCRs] and via modulation of ocean and atmospheric oscillations such as ENSO, the North Atlantic Oscillation [NAO] and Quasi-Biennial Oscillation [QBO]. The QBO in turn affects planetary scale waves such as Rossby Waves, the jet stream, and the polar vortex. Solar minimums have been linked to the negative phase of the NAO, which in turn causes colder winters in Europe and recovery of Arctic sea ice. 

These are only a few of the solar amplification mechanisms outlined in the excellent lecture slides below from a conference on climate impacts of solar radiation, which demonstrate the solar-climate connection is far more complex than the simplistic assumptions used in climate models. 

1 comment:

  1. Left out of this brief summary and perhaps the paper itself is the fact that a greater percentage of short wave radiation is reflected back into space.

    In effect, if TSI does not vary much while SW radiation varies a lot, the net effect will be the same as substantial variation in the Earth's albedo.

    Of course this has been quantified by NASA scientists.

    In 20012 Norman Loeb and others published a study that claimed,

    “Coupled Model Intercomparison Project 3 (CMIP3) simulations for the A1B scenario from 15 coupled atmosphere-ocean models exhibit a large spread in annual mean net TOA flux during the past decade, ranging from 0.09 to 1.5Wm-2 (Fig. 3b, grey bar). Interannual variability of net TOA flux in the models is surprisingly large: the standard deviation in model net TOA flux between 2001 and 2010 exceeds that from the observations in 11 of the 15 models considered.”

    (Loeb et al, Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty. Nature Geoscience VOL 5 February 2012.


    An earlier paper from the same team had already establish that estimates of flux at TOA are based on data that has substantial calibration errors.

    Loeb et al (2009) summarized the combined effect of all of these errors they found. When estimates of solar irradiance, SW and LW TOA fluxes are combined, taking account of +0.85+/-0.15 W/m2 heat storage by the oceans, the possible range of TOA flux becomes ) MINUS 2.1 to plus 6.7 Wm-2.

    In 2009 Loeb et al reported miscalibration of satellite instruments and errors in estimating other parameters on which the global radiation budget of Trenberth had relied. (K. E., 1997: J. Climate, 10, 2796–2809.)


    I conclude both that:

    !. Interannual variability of TOA radiation flux is substantially greater than generally believed and

    2. Neither the classical approach (Atmospheric Radiation, Goody & Yung, 1989) nor the satellite observations by NASA and others constrain the estimates of flux imbalance at the TOA sufficiently to determine if and by how much the Earth is warming or cooling.

    3. Coupled atmosphere-ocean models produce whatever estimates their designers build into them based on their assumptions and parameter values they choose.