Solar cycle antiphase irradiance

Posted: September 29, 2013 by tchannon in Solar physics

Fig. 1. The solar spectral irradiance as inferred from SORCE and TIMED observations only, from 22 April 2004 till 23 July 2010.
(A) shows the average solar spectral irradiance for that period. A black-body model has been used to extend the SSI for wave lengths beyond 1580nm. (B) displays the characteristic altitude of absorption in the Earth’s atmosphere for each wavelength, defined as the altitude at which the optical depth equals one. (C) shows the relative variability (peak to peak/average) for solar cycle variations inferred from measurements obtained between 22 April 2004 and 23 July 2010. Spectral regions, where the variability is in phase with the solar cycle (represented by, e.g. the sunspot number or the TSI) are marked in red, while blue denotes ranges where the variability measured by SORCE is out-of-phase with the solar cycle. These phases, as well as the magnitude of the variability in the UV, are not all reproduced by models and other observations (see Sect. 3 as well as Figs. 2, 7 and 8), and thus should be considered with care. (D) shows the absolute variability, which peaks strongly in the near-UV.

Recent variability of the solar spectral irradiance and its impact on climate modelling

I. Ermolli1, K. Matthes2, T. Dudok de Wit3, N. A. Krivova4, K. Tourpali5, M. Weber6, Y. C. Unruh7, L. Gray8, U. Langematz9, P. Pilewskie10, E. Rozanov11,12, W. Schmutz11, A. Shapiro11, S. K. Solanki 4,13, and T. N. Woods10

  1. INAF, Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy
  2. GEOMAR I Helmholtz-Zentrum für Ozeanforschung Kiel, Kiel, Germany
  3. LPC2E, CNRS and University of Orléans, Orléans, France
  4. Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
  5. Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece
  6. Institut für Umweltphysik, Universität Bremen FB1, Bremen, Germany
  7. Astrophysics Group, Blackett Laboratory, Imperial College London, SW7 2AZ, UK
  8. Centre for Atmospheric Sciences, Dept. of Atmospheric, Oceanic and Planetary Physics, University of Oxford, UK
  9. Institut für Meteorologie, Freie Universität Berlin, Berlin, Germany
  10. University of Colorado, Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
  11. Physikalisch-Meteorologisches Observatorium, World Radiation Center, Davos Dorf, Switzerland
  12. IAC ETH, Zurich, Switzerland
  13. School of Space Research, Kyung Hee University, Yongin, Gyeonggi 46-701, Republic of Korea

Correspondence to: I. Ermolli
Received: 29 July 2012 – Published in Atmos. Chem. Phys. Discuss.: 19 September 2012
Revised: 6 March 2013 – Accepted: 13 March 2013 – Published: 17 April 2013

Atmos. Chem. Phys., 13, 3945–3977, 2013
© Author(s) 2013. CC Attribution 3.0 License.

First few lines of a long abstract from a 33 page paper.

Abstract. The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. …

Many authors for a paper where the abstract contains “this might have significant implications on the Earth’s atmosphere”?

The irradiance spectral balance vs. frequency is varying in time.

Posted by Tim

  1. J Martin says:

    Is TSI the same as SSI, or does it exclude EUV and XUV ?

    Or is TSI only the irradiance that is in phase ?

  2. ren says:

    I do not know about you, but I see a clear correspondence between solar activity and temperature of the stratosphere above the equator.

  3. tchannon says:

    The usual is ‘TSI at earth distance’.

    Instruments are very simple, kind of actinometer. This is a dubious definition, just means heat measuring.

    In practice the late 19th cent. Angstrom electrical servo loop actinometer is used, wrapped in a cavity (thermally conductive black box with a hole) and obfuscated as some fancy modern device. The servo loop adjusts a heater for an identical effect to what is being measured. Done this way so most errors cancel to zero. Electrical heater power is the measure. Originally simply a heating resistor and a meter to measure the current. P = I^2 .

    The following can be reduced to the above.

    Here is a link to a fair size PDF which has cross section drawings and concept diagrams of a real absolute cavity radiometer. NREL report from 1996.
    “Calibration of a Solar Absolute Cavity Radiometer with Traceability to the World Radiometric Reference”

    Click to access 20619.pdf

    These instruments do not distinguish between wavelengths of radiation, are broadband… or are supposed to be. In practice nothing is perfect.

    The paper which is the subject of this article deals in radiation intensity vs. wavelength. In theory if all wavelengths were measured (can’t be done) the sum would equal TSI.

  4. Tenuk says:

    Good find Tim. As usual, it’s models all the way down, “…spectral irradiance as inferred…” “…shows the average solar spectral irradiance for that period. A black-body model has been used to extend the SSI for wave lengths beyond 1580nm…”

    I’m sure Leif S was rubbishing the amount of spectral change in the UV being assumed from Source data on one of the recent WUWT solar threads. Don’t know if this was just hubris or there really is no way of accurately measuring spectral solar variance. The assumption that the sun radiates as an ideal black body is worrying.

  5. tchannon says:

    I wonder how much of what is discussed is merely sunspot effect, cold centre hot ring?

  6. suricat says:

    tchannon says: September 30, 2013 at 12:25 am

    “cold centre hot ring?”

    IMHO, I dispute this definition. The ‘hot ring’ is detectable, but the ‘cold centre’ defies detection by the method of observation. It’s illogical that the ‘hot ring’ that, in 2D, encompasses/surrounds a Solar ‘energy’ eruption doesn’t indicate more ‘shorter wavelength’ emanations from the ‘centre’ of the eruption at Sol’s surface.

    Do these ‘cold’ emissions remain undetected by ‘any’ means?

    We really need to know the ‘absolute’ spectra involved.

    Best regards, Ray.

  7. pochas says:

    Some idea of where the EUV emissions are coming from can be gotten from the SDO images. All of the images except the AIA 4500 are in the ultraviolet range. The shortest, AIA 094 would correspond to 9.4 nm above.

  8. ren says:

    You can see that the low activity causes a decrease in temperature in the stratosphere, but at high latitudes there is a sudden temperature increase, which is very visible in the graphs. This can be very important for winter forecasts over long periods of low solar activity.

  9. ren says:

    Current blockade in the north at an altitude of 20 km. Jetstream runs along the border of the yellow area.

  10. Geoff Sharp says:

    Unfortunately this paper is just a talkfest summary of the Stratospheric science of the past decade and offers nothing new to our understanding.

    I wonder the cost to the taxpayer that could be better spent….

  11. suricat says:

    pochas says: September 30, 2013 at 5:23 am

    What an excellent link pochas. There’s also a graph on the page.

    I think Tim was hinting that observations (as defined) are not as well observed as they should be, and I must concur. The idiom that sunspots are cold regions, because they’re dark, is counter intuitive to reality. The reason sunspots are ‘dark’ is because they don’t emit EM energy in the ‘vis spectra’ (visible spectrum). Whereas, some individuals (by genetic fluke), can see UVa, there are no individuals that can see UVb, UVc, soft X-ray, X-ray, hard X-ray, or gamma ray ‘electromagnetic emissions’ (non particle magnetic flux ‘vibrations’ [ignoring the Higgs field]).

    Your link includes;

    which shows a ‘soft X-ray’ filtered image which shows that the energy emission from a ‘sunspot’ is at a ‘wavelength’ greatly shorter than the ‘vis’ spectra (the ‘spot’ is the ‘illumination point’). I’m not inferring that the w/m^2 is high (because it’s difficult to assign ‘heating effect’ to energy levels of this magnitude), I’m just suggesting that the ‘source emission’ is invisible to current observation protocol.

    As for the ‘graph’;

    The mauve, 0.1-7nm trace, shows greatest variability and is partially reflected in the ochre/yellow, 30.4nm trace. This indicates, to me, that the source energy is attracted towards these ‘resonance’ frequencies/wavelengths. IMHO, the initial ‘frequency’ (before ‘splitting’) may be well above the frequencies that we observe.

    Best regards, Ray.

  12. Brett Keane says:

    I was led to my current studies in Physics via my applied plant science background (the climate connection). But I do remember, living east of the Tasman Sea, and just north of the antarctic convergences, that the BAS interest in ozone seemed to follow the IQSY and IGY. That dates me, aye. We did better with dogs and ice-modified Fergy tractors than catamarans,excepting the sled types.

    Can anyone comment on whether the ozone hole kerfuffle might be linked to the quiet sun, and possible misunderstanding of solar energetics cycles? This solar stuff, very logical, is taking me into yet more interesting territory. Brett Keane