Decapitation of high-altitude glaciers on the Tibetan Plateau revealed by ice core tritium and mercury records

Abstract

Two ice cores were retrieved from high elevations (∼ 5800 m a.s.l.) at Mt. Nyainqentanglha and Mt. Geladaindong in the southern to inland Tibetan Plateau. The combined analysis of tritium ( 3 H), 210 Pb, mercury tracers, along with other chemical records, revealed that the two coring sites had not received net ice accumulation since at least the 5 1950s and 1980s, respectively, implying an annual ice loss rate of more than several hundred millimeter water equivalent over these periods. Both mass balance modeling at the sites and in situ data from nearby glaciers confirmed a continuously negative mass balance (or mass loss) in the region due to the dramatic warming in the last decades. Along with a recent report on Naimona'nyi Glacier in the Himalaya, the find-10 ings suggest that glacier decapitation (i.e., the loss of the accumulation zone) is a widespread phenomenon from the southern to inland Tibetan Plateau even at the summit regions. This raises concerns over the rapid rate of glacier ice loss and associated changes in surface glacier runoff, water availability, and sea levels. et al., 2012). In situ stake observations have also confirmed a continuously negative 419 Abstract Introduction Conclusions ReferencesTables central Asia (Bryson, 1986). The TP blocks mid-latitude westerlies, splitting the jet into two currents that flow the south and north of the plateau, respectively. The plateau is 420 Abstract Introduction Tables Abstract Introduction Conclusions References Tables Abstract Introduction Conclusions References Tables 25 Conclusions References

Twentieth century dust lows and the weakening of the westerly winds over the Tibetan Plateau

“…A total of 3585 coregistered samples were collected for major soluble ions (Na + , K + , Mg 2+ , Ca 2+ , Cl − , NO 3 − , and SO 4 2− ), major and trace elements (Ca, Al, S, Mg, Fe, K, Na, and Bi,) and stable isotopes ( δ 18 O) (see supporting information Text S2). In addition, samples were collected for tritium and 210 Pb analysis [ Kang et al ., ] (see supporting information Text S2).…”

Black carbon concentrations from a Tibetan Plateau ice core spanning 1843–1982: recent increases due to emissions and glacier melt

“…Glacier retreat in recent decades is widespread across the Tibetan Plateau (Yao et al, 2012). Specific to the Geladaindong region, Kang et al (2013) show that Geladaindong (5750 m) and nearby Nyainqentanglha (5850 m) have not received net accumulation since the 1980s and 1950s, respectively. This indicates widespread melt in the region in recent decades, consistent with results previously reported in the Himalaya (Kehrwald et al, 2008).…”

“…• 10.76 E, 5750 m a.s.l.) located in the Tanggula Mountains of the central Tibetan Plateau (Kang et al, 2013) (Fig. 1).…”

“…18 O by mass spectrometry, all performed at the Climate Change Institute of the University of Maine (Grigholm et al, 2013). The ice core was dated by counting the annual layer signal from isotopes, ions, and trace elements, and verified using known age horizons from tritium that peak in 1963, 210 Pb and several volcanic markers (Kang et al, 2013). Although the ice core was recovered in 2005, annual mass loss of ice at this location has resulted in the loss of the most recent 22 yr of the record, and the top of the core is dated to 1982 AD (Kang et al, 2013).…”

“…The ice core was dated by counting the annual layer signal from isotopes, ions, and trace elements, and verified using known age horizons from tritium that peak in 1963, 210 Pb and several volcanic markers (Kang et al, 2013). Although the ice core was recovered in 2005, annual mass loss of ice at this location has resulted in the loss of the most recent 22 yr of the record, and the top of the core is dated to 1982 AD (Kang et al, 2013). To account for changes in sample resolution with depth in the ice core due to glacier thinning, the high-resolution M BC and Fe (used as a proxy for dust) data were re-sampled to three samples per year.…”