气候变化领域集成服务门户

A 32.4 m shallow ice core was recovered from a site at 5743 m above sea level on the Mt. Tanggula in the central Qinghai-Tibetan Plateau in August 2005. A total of 630 samples were analyzed for major ions (Na(+), NH(4)(+), K(+), Mg(2+), Ca(2+), Cl(-), SO(4)(2-) and NO(3)(-)) and stable oxygen isotope ratios (delta(18)O). The ion chemistry of the upper 14.5 m, covering the last 55 years, is characterized by mineral dust (HCO(3)(-), Ca(2+), SO(4)(2-), Na(+), Cl(-) and K(+)), anthropogenic species (SO(4)(2-), NH(4)(+) and NO(3)(-)) and soil and biogenic emissions (NO(3)(-) and NH(4)(+)). Ca(2+) is the dominant cation in the core with a medium value of 33.5 mu eg L(-1), accounting for 64.5% of the total cations, and HCO(3)(-) is the predominant anion, accounting for 80.2% of the total anions. Compared with ice core records from Altai and Himalayas, at the northern and southern margin of the Qinghai-Tibetan Plateau, respectively, major ion concentrations (except SO(4)(2-), NH(4)(+) and NO(3)(-)) in Tanggula ice core are much higher due to pronounced regional crustal aerosol inputs. Increasing SO(4)(2-) concentrations in the most recent 50 years are attributed to anthropogenic contributions; but mineral dust is still the major sources for SO(4)(2-) in the central Qinghai-Tibetan Plateau. The notable relationship between increasing Northern Hemisphere temperature and NO(3)(-) and NH(4)(+) concentrations suggests that recent temperature increase in Qinghai-Tibetan Plateau may be enhancing biological activity and associated NO(3)(-) and NH(4)(+) emissions from the regional terrestrial ecosystems. (C) 2010 Elsevier B.V. All rights reserved.