CM35: Cosmic Rays (CR) events before 1000 AD (774-775 and 994) in some proxies.
Here used: ca667, yamal, ak096, chin046, GRIP, Pages2k.

The paper I started from:
Miyake et al, 2015: Cosmic ray event of A.D. 774-775 shown in quasi-annual 10 Be data from the Antarctic Dome Fuji ice core, Geophys. Res. Lett., 42,1, 84-89, doi:10.1002/2014GL062218

14C content in tree rings and 10Be concentration records in polar ice core provide information about past cosmic ray intensities. The A.D. 774-775 cosmic ray event has been identified by 14C measurement in several tree rings from all over the world. Although the quasi-decadal 10Be Dome Fuji data in the Antarctic ice core also shows a sharp peak around A.D. 775, annual 10Be variations in the Dome Fuji core or in other cores have not been revealed. We have measured quasi-annual 10Be concentrations from approximately A.D. 763-794 in the Dome Fuji ice core, and detected a clear increase (~80% above the baseline) in 10Be concentration around A.D. 775. However, an accurate height of this increase is not straightforwardly estimated due to the background variation in 10Be concentration. The 10Be increase can be due to the same cosmic ray event as shown in the 14C content in A.D. 774-775.
Please note at page 86 of the paper:"An apparent peak of the 10Be concentration is observed, near the A.D. 774/775 event (at A.D. 780 of the 10Be- 14 C age)".
So, in the 6-plots figures I did subtract 5 years in order to have pure AD age -and not 10Be-14C age- for correct comparison between the 10Be CR event and any other proxy. I need to understand why such an age difference holds. At page 87 of the paper: "Therefore, we can conclude that the 10Be event of A.D. 780 consists of superposition of background variation and the cosmic ray event signal, which is larger than the background variation, and can reflect the A.D. 775 cosmic ray event within the time resolution of the decadal 10 Be- 14 C age model (i.e., the apparent 5 year delay of the 10 Be peak can be ascribed to the uncertainty of the age model, which is a dozen years or so in maximum)"
See e.g. some (freely available) research papers on Be/C age:
  • Steinhilber et al, 2012
  • Briner et al, 2014 and its S.I.
  • Favilli et al, 2009 (fig.4 interesting)
  • Shen et al, 2004

  • Other papers (paywalled):
    to author's library,             to doi:

  • Miyake et al., 2012 , abstract
  • Usoskin et al., 2013 , abstract
  • Usoskin & Kovaltsov, 2012 , abstract
  • Usoskin & Kovaltsov, 2014 , abstract

  • All proxy data used here for plots, have been scaled to 0-1000 y-range by:
    SCAL-SCAL0         scal range
    ------------   =  ------------       or    SCAL=SCAL0+[RANGE(SCAL)/RANGE(VAL)]*(VAL-VAL0)
     VAL-VAL0          val range
    where: SCAL= scaled value (0-1000); SCAL0= min of scaled range (0); VAL= proxy value to be scaled; VAL0= min of value range (variable)
    scal range= scaled range (0-1000); val range= proxy range (variable)

    So, we have:
    scaled from orig
    value "val"
    back to orig
    775: lines
    994: lines
    ca667scal=val*1.5391000/6500, 650scal/1.5393357/34573607/3707
    yamalscal=val*51000/2000, 200scal/51472/15721722/1822
    ak096scal=val*0.51000/20000, 2000scal*292/192342/442
    chin046scal=val*251000/400, 40scal/25259/359509/609
    gripscal=(val+38)*166.671000/6-38, -32scal/166.67-381312/14931765/1947
    pages2kscal=(val+2)*333.331000/3-2, -1scal/333.33-2790/8901040/1140
    fujiscal=val*55.5561000/180, 18scal/55.5564/38 no data
    Δ14Cscal=(val+10)*33.3331000/30-10, 20scal/33.333-103/24 3/24

    Page written: 9.2.15.         Last Update: 17.2.15