Search

Sampling of atmospheric aerosol particles was carried out at Syowa station, Antarctica (39.58°E, 69.00°S) in 1998. For a better understanding of sea-salt chemistry in the coastal Antarctic regions, individual sea-salt particles were analysed using a scanning electron microscope equipped with energy dispersive X-ray spectrometer (SEM-EDX). Individual particle analysis indicates that more sea-salt particles were modified in fine particles (0.2–2 μm in diameter) through heterogeneous reactions mainly with gaseous sulfur species in the summer and reactive nitrogen oxides in the winter–spring. In particular, sea-salt particles in the coastal Antarctic atmosphere may be modified by heterogeneous reactions with not only SO 2 and H 2 SO 4 but also volatile sulfur species (e.g. CH 3 SO 3 H, DMS and DMSO) derived from bioactivity on the ocean surface during the summer. Also, low air temperature and a larger extent of sea ice offshore Syowa probably enhanced release of fractionated sea-salt particles (S-rich, Mg-rich, K-rich and Ca-rich) from the surface of snow and sea ice, particularly in September–October 1998. In addition, we attempt to estimate the scavenging rate of atmospheric sulfur species and reactive nitrogen oxides by dry deposition of sea-salt particles. Our estimation suggests that the upper limit of the scavenging rate of atmospheric sulfur species by sea-salt particles could rise to approximately 0.5 nmol m −2 day −1 at Syowa station during the summer. This value corresponded to about 30% of the concentration of particulate sulfur species such as non-sea-salt (nss)-SO 2− 4 and CH 3 SO − 3 and ∼10% of total atmospheric sulfur species (nss-SO 2− 4 , CH 3 SO − 3 and SO 2 ). In contrast, the estimated NO − 3 scavenging rate by sea-salt particles was ∼0.2 nmol m −2 day −1 , which is similar to the dry deposition rate of HNO 3 +N 2 O 5 (approximately 0.2–0.3 nmol m −2 day −1 ). Hence, sea-salt particles probably play an important role as scavengers of acidic species in the coastal Antarctic regions. DOI: 10.1111/j.1600-0889.2005.00142.x

Systematic collections of stratospheric air samples have been conducted over Japan since 1985 using a balloon-borne cryogenic sampler. The collection of stratospheric air samples was also carried out twice over Scandinavia and once over Antarctica. Vertical profiles of CO 2 concentration thus obtained over these locations were quite similar to each other; CO 2 concentration decreased with increasing altitude in the lower stratosphere and reached an almost constant value in the mid-stratosphere. δ 13 C of stratospheric CO 2 observed over these locations enriched with increasing altitude. A negative correlation between δ 13 C and CO 2 concentration with Δδ 13 C/ΔCO 2 of −0.02‰ ppmv −1 was found in the lower stratosphere. Although CO 2 concentration was almost constant in the mid-stratosphere, the δ 13 C enrichment was observed in succession. δ 18 O of stratospheric CO 2 also enriched with increasing altitude. The enrichment was significant; δ 18 O was almost 0‰ at the tropopause and reached a maximum value of about 11‰ at a layer with N 2 O concentration of about 10 ppbv. A compact relation between δ 18 O and N 2 O concentration was consistently observed for these locations. Stratosperic CO 2 over Japan showed a secular increase with an average rate of 1.4 ppmv yr −1 for the period 1985–2000. The secular increase was not constant with time, and temporal stagnation of the CO 2 increase was observed in 1997. DOI: 10.1034/j.1600-0889.2003.00059.x

In order to elucidate the seasonal and interannual variations of oceanic CO2 uptake in the Greenland Sea and the Barents Sea, the partial pressure of CO2 in the surface ocean (pCO2sea) was measured in all seasons between 1992 and 2001. We derived monthly varying relationships between pCO2sea and sea surface temperature (SST) and combined them with the SST data from the NCEP/NCAR reanalysis to determine pCO2sea and air–sea CO2 flux in these seas. The pCO2sea values were normalized to the year 1995 by assuming that pCO2sea increased at the same growth rate (1.5 μatm yr−1) of the pCO2 in the air (pCO2air) between 1992 and 2001. In 1995, the annual net air–sea CO2 fluxes were evaluated to be 52 ± 20 gC m−2 yr−1 in the Greenland Sea and 46 ± 18 gC m−2 yr−1 in the Barents Sea. The CO2 flux into the ocean reached its maximum in winter and minimum in summer. The wind speed and ΔpCO2 (=pCO2air–pCO2sea) exerted a greater influence on the seasonal variation than the sea ice coverage. The annual CO2uptake examined in this study (70°–80°N, 20°W–40°E) was estimated to be 0.050 ± 0.020 GtCyr−1 in 1995. The interannual variation in the annual CO2 uptake was found to be positively correlated with the North Atlantic Oscillation Index (NAOI) via wind strength but negatively correlated with ΔpCO2 and the sea ice coverage. The present results indicate that the variability in wind speed and sea ice coverage play a major role, while that in ΔpCO2 plays a minor role, in determining the interannual variation of CO2 uptake in this area.DOI: 10.1111/j.1600-0889.2006.00178.x

Precise and continuous measurements of the atmospheric CO 2 concentration have been made at Syowa Station, Antarctica since February 1984. The diurnal CO 2 variation was hardly observable throughout the year. The secular CO 2 trend was variable with time, showing slow increase in 1984, 1986 and 1988 and rapid increase in 1985 and 1987. The annual CO 2 increase was especially large in 1987, which may be related to the 1986/1987 ENSO event. The average rate of annual CO 2 increase over the last 5 years was about 1.6 ppmv yr -1 . The average seasonal CO 2 cycle showed minimum and maximum concentrations in mid-April and early in October, respectively, and its peak-to-peak amplitude was about 1.1 ppmv. The measured seasonal cycle was variable from year to year, but there was no indication of a long-term increase of the amplitude. It was found that irregular CO 2 variations with amplitudes of 0.2 ppmv at most and periods of a few weeks show high correlation with airmass exchange by synoptic scale weather disturbances. The results from Syowa are compared with those from the South Pole and Cape Grim, Tasmania. DOI: 10.1034/j.1600-0889.1991.00007.x