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

A 51.85-m tim core collected from site DT001 （accumulation rate 127 kgm^-2a^-1, mean annual temperature -33.1 ℃） 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 ℃ 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 Mg^2＋ are similar to those reported from other sites in East Antarctica. However, the mean concentration of Ca^2＋ 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.

Chemical Characteristics and Environmental Records of a Snow-Pit at the Glacier No.12 in the Laohugou Valley, Qilian Mountains

In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l, in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxygen isotopes （6180） and major soluble ions were measured. Results showed that Ca2＋ is the dominant cation, and SO42 is the dominant anion. All major ions have close positive correlations with eachother except NO3 and NH4＋. 6180 show positive correlation with air temperature. The method of correlation analysis, sea-salt ion tracer and trend analysis were used to determine the source of the chemical components. The correlation analysis and HYSPLIT backward trajectory analysis suggest that atmospheric soluble dust species dominate the chemical signature.

Anions and Cations in a Snow Pit on the Top of Nelson Ice Cap,the Southern Shetland Islands,Antarctica

The Antarctic Ice Sheet contains a lot of detailed records of the changing processes of the environment, climate and the industrialization. In recent years, the glaciochemistry has been progressing rapidly. Soluble ions are the major impurity deposited on polar glaciers and also are an important aspect of glaciochemistry. Previous studies have covered several locations of Antarctica except the region around the Great Wall Station of China.