A continuous ice-core Be-10 record from Mongolian mid-latitudes : Influences of solar variability and local climate

• High-resolution Be-10 records used for studies of detailed changes in atmospheric Be-10 production rates predominantly derive from polar ice cores. In this study, we present the first Be-10 record from a mid latitude ice core. The ice core derives from the Tsambagarav mountain range located in the Mongolian Altai region. The new Be-10 concentration record spans the period from AD 1550 to 2009, while the flux record extends from AD 1816 to 2009. The Be-10 concentration in the Tsambagarav ice core ranges between similar to 1.5 x 10(4) and similar to 10 x 10(4) atoms g(-1), whereas the Be-10 flux changes from similar to 0.02 to similar to 0.15 atoms cm(-2) s(-1) The average Be-10 flux at Tsambagarav is four times higher than the average Be-10 flux recorded in the NGRIP and Dome Fuji ice cores, which is in accordance with model predictions. In general, the long-term trends observed in the Tsambagarav Be-10 concentration and flux records are reasonably similar to those observed in the NGRIP ice core. A comparison between the Tsambagarav Be-10 record, group sunspot numbers (GSNs), and solar modulation potentials based on C-14 in tree rings suggests that the Maunder Minimum was associated with a prolonged maximum in Be-10 concentrations at Tsambagarav, whereas the Dalton Minimum was associated with a minor increase in the Be-10 concentration and flux that was delayed relative to the primary minimum in GSNs. The sulphate record from Tsambagarav shows that large positive anomalies in the sulphate concentration are associated with negative anomalies in the Be-10 concentration. A concurrent positive sulphate anomaly may explain why the main phase of the Dalton Minimum is subdued in the Be-10 record from Tsambagaray. Spectral analysis indicates that the 11-yr solar-cycle signal may have influenced the new Be-10 record, but the evidence supporting a direct link is ambiguous. Local and regional climatic changes, such as cyclonic versus anticyclonic conditions and related storm tracks, most likely played a significant role for the Be-10 deposition in the Tsambagarav region.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Klimatforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Climate Research (hsv//eng)

Keyword

cosmogenic nuclide

beryllium 10

mid-latitude

past solar activity

climate

Publication and Content Type

ref (subject category)

art (subject category)