General tendencies of stable isotopes and major chemical constituents of the Dome Fuji deep ice core (scientific paper)

Stable isotope compositions of water and major chemical constituents of the Dome Fuji ice core are analyzed and the data sets over the entire depth of the 2503-m core are presented in appropriate time resolution as consecutive series of average value in definite terms. These results based on the first stage analyses allow a temporal climatic dividing of the three glacial-interglacial cycles present in the records. A Comparison of the climatic and environmental characteristics of these climate stages is presented

Distribution of chemical elements in the snow at the site S25 in Antarctica

The firn block samples, being 50cm deep and covering nearly one-year formation, were taken at the site S25 on Antarctic ice sheet near Syowa Station. The vertical distribution of Cl, Na, and SO_4 showed high and nearly constant level in the upper 37.5cm (766 ppb, 425 ppb, and 119 ppb, respectively) which accumulated within the period from the autumn of 1985 (based on the distribution of major elements) to early summer of 1986 when high influence of marine air is expected. On the other hand, very low concentration levels of these species (219 ppb, 117 ppb, and 64 ppb, respectively), but with high SO_4/Na ratio, were found in the lower 12.5cm layer which accumulated in the late summer of 1985 when concentration of SO_4 aerosols is high. NO_3 showed several peaks in the upper 37.5cm and K and NH_4 low level. The mean concentrations of Al, Fe, Zn, and Cu were 323 ppt, 251 ppt, 435 ppt, and 118 ppt, respectively. These concentration levels are much higher than those reported for snow and ice from inland area but comparable with those measured at the Syowa Station and the site S16 near the site S25. The metal organic compounds of these heavy metal elements were firstly determined in the Antarctic snow and their contributions to the total amounts were significant. This new finding, in association with the observation that the organic heavy metal compounds has also been found in atmospheric aerosols collected in the Antarctic air as well as in the marine air, suggests their new possible origin and path to the Antarctica

Gaseous acids in the atmosphere at Syowa Station, Antarctica (abstract)

Seasonal variation of atmospheric aerosols and gaseous acids in the atmosphere at Syowa Station was observed during JARE-31 by the use of a 3-stage air filter unit which consists of an 0.

The test of marine aerosol sampling aboard the research vessel "SHIRASE" (abstract)

The research vessel "SHIRASE" was used for test sailing from Tateyama in Chiba prefecture to Nagoya via Miyake Island in September 1987. Marine aerosols were measured aboard every hour b

Analytical method for small amount of polar snow and ice samples by ion chromatography

Ion chromatography is one of the major methods for analyzing many kinds of anions and cations in a liquid solutions in a short time. In this time, we measured anions and cations in snow and ice collected in polar regions. The generally concentration is under 100μg/l. The accumulation rate of snow in most of the regions is very low. Therefore the samples were very small. The transportation of samples is sometimes so difficult that it is useful to decrease the amounts to analyze. We considered to analyze the very small samples containing very trace level concentration of ions in snow and ice in polar regions by ion chromatography. As a result, we could measure both anions and cations at about only 1.5ml. It was also possible to measure 8 kinds of ions (CH_3 COO^-, HCOO^-, C_2O_4^, CH_3SO_3^-, F^-, PO_4^, NO_2^- and NH_4^+) together with major 7 kinds of ions (Cl^-, NO_3^-, SO_4^, Na^+, K^+, Mg^, Ca^)

The behavior of chemical compositions in the snow and atmosphere on the Mizuho Plateau

Atmospheric aerosols were studied at Syowa Station, Antarctica for 3 years from 1988 to 1990. Some chemical species, such as exSO_4^, MSA and NH_4^+, showed an annual trend, high in summer and low in winter. The seasonal variations of gaseous HCl, SO_2,HNO_2,HNO_3 were also studied and the occurrence of very high HCl gas in summer and the comparable concentrations of others gases to those of aerosols were found. The size distribution of aerosol particles over inland area and marine water were measured. The particle radius at the concentration maximum of exSO_4^ as well as MSA were found at 0.35μm, indicating secondary particles production from gases. In most case, atmospheric aerosols had negative exCl^- value showing Cl^- defect as compared to Na^+. From the observation at 5 snow pits on the Mizuho Plateau, apparent seasonal variations in δ^O, Cl^- and Na^+ were found only at the 2 inland points. From the drifting snow studies, Cl^-, Na^+, exSO_4^, NO_3^- and MSA showed the distribution of high in sea-side and low in inland and then re-increase in the inner area indicating supply from inland. Most snow samples showed positive exCl^- values. A rough linear relationship among concentrations in chemical species was found between atmospheric aerosols and corresponding snow on the Mizuho Plateau and, therefore, the concentration in the aerosol is roughly reflected in the snow composition. However, the supply of chemical substances to snow from other sources than ground-level aerosols would be needed to account for the fact that some chemical items such as exCl^-, Ca^ and K^+ apparently do not satisfy the above linear relation

CHEMICAL NATURE OF HEAVY METAL ELEMENTS IN ANTARCTIC SNOW

Analysis of firn block samples from site S25 near Syowa Station revealed that significant parts of Al, Fe, Zn and Cu are contained in the snow sample as organic metal compounds. They dissolve into the melt water of the snow sample and become reactive only after oxidative digestion with HClO_4 and HNO_3. The same organic metal compounds were found in atmospheric aerosols collected at Syowa Station and Mizuho Station, which suggests that these were incorporated into the snow from atmospheric aerosols. The above observation, in association with the finding that these organic metal compounds also exist in aerosols from the North Pacific as well as from the Southern Sea, indicates that these compounds are widely distributed in the global atmosphere and further suggests the existence of gaseous organic metal compounds in the air as a precursor of these compounds in the aerosols. The samples of snow from site S25 and atmospheric aerosols from the Southern Sea were subjected to volatilization experiments in the vacuum and the vapor was collected in the cold trap immersed into the liquid N_2. Significant amounts of the heavy metals were found in the cold trap, showing the volatile nature of these heavy metal elements contained in the Antarctic snow and aerosols. These results support the idea that the gaseous organic metal compounds exist in the air as a precursor of aerosols. Experiments to directly determine the gaseous organic metal compounds are now in progress

DISTRIBUTION OF CHEMICAL COMPONENTS BETWEEN ATMOSPHERE AND SNOW PHASES IN EAST QUEEN MAUD LAND

It is certain that all chemical components contained in Antarctic ice have been derived from the atmosphere. However, the detailed mechanism of their inclusion into glacier ice is still a subject of research. Comparisons of chemical composition of atmospheric aerosol and falling snow or surface depositing snow have been carried out at the South Pole Station and Antarctic Peninsula areas and good linear relationships have been found, especially in the latter case. But these studies were focused on the behavior of heavy metal elements. Furthermore, the same kinds of studies carried out in Alaska gave a negative conclusion. The authors studied the relationship between chemical compositions of atmospheric aerosol and fresh drifting snow in 1990-1993 on the Mizuho Plateau and found a loose linear relationship with regard to the most of main chemical species contained in aerosol and snow. The extent to which the linear relationship holds differs among chemical species. Even with such uncertainty, these results suggest a general conclusion that the chemical composition of impurities contained in Antarctic glacier ice is ultimately controlled by surface aerosols. In 1993-1994,the study was repeated with the expanded survey area from the sea surface to near the Dome Fuji Station. However, this time the linear relationship was much more diffuse than expected from previous studies. Most typically, quite different results were observed by duplicate sampling with time lag of nearly a month, one with a linear relationship and the other without it. These results suggest the necessity of more basic studies of factors determining chemical composition of Antarctic snow and ice for better understanding of the Antarctic ice core