Journal of Geographical Sciences ›› 2006, Vol. 16 ›› Issue (1): 23-33.doi: 10.1007/s11442-006-0103-5

• Climate and Environmental Change • Previous Articles     Next Articles

250 years of accumulation, oxygen isotope and chemical records in a firn core from Princess Elizabeth Land, East Antarctica

ZHANG Mingjun1,2, LI Zhongqin2, REN Jiawen2, XIAO Cunde2, QIN Dahe2, KANG Jiancheng3, LI Jun4   

  1. 1. Geography and Environment College of Northwest Normal University, Lanzhou 730070, China
    2. Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China
    3. Chinese Institute of Polar Research, Shanghai 200129, China
    4. Antarctic Cooperation Research Center and Australian Antarctic Division, Hobart 7001, Australia
  • Received:2005-10-20 Revised:2005-11-21 Online:2006-03-25 Published:2006-03-25
  • Supported by:

    The Key International Cooperation Project of the Ministry of Science and Technology of China, No. 2001CB711003; Knowledge Innovation Project of CAS, No.KZCX3-SW-354

Abstract:

A 51.85-m firn core collected from site DT001 (accumulation rate 127 kgm-2a-1, mean annual temperature -33.1 oC) on Princess Elizabeth Land, East Antarctica, during the 1996-97 Chinese First Antarctic Inland Expedition has been analyzed for chemical composition and oxygen isotope ratio. A comparison between the seasonal variations of major ions was carried out in order to reduce the dating uncertainty, using the volcanic markers as time constrains. A deposition period of 251 years was determined. The calculated accumulation rates display an increasing trend before 1820, while after 1820, the trend of the accumulation is not obvious. Overall, temperature change in the region shows a slight increasing trend over the past 250 years. But, notably, a temperature decline of -2 oC is observed from 1860 to the present. This feature, at odds with the warming trend over the past century recorded in both hemispheres, likely reflects a regional characteristic related to the lack of a high latitude/low latitude link in the Southern Hemisphere circulation patterns. The results of the glaciochemical records of the firn core show that the mean concentrations of Cl-, Na+ and Mg2+ are similar to those reported from other sites in East Antarctica. However, the mean concentration of Ca2+ is much higher than that reported from other regions, suggesting the influence of the strong local terrestrial sources in Princess Elizabeth Land. There is no evidence of a positive correlation between NO3- concentrations and solar activity (11-year solar cycle and solar cycle length), although solar proton events may account for some of the NO3- peak values in the record.

Key words: firn core, δ18O, accumulation rate, glaciochemistry, Antarctic ice sheet