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The air-sea-ice CO2 flux was measured in the ice-covered Saroma-ko, a lagoon on the northeastern coast of Hokkaido, Japan, using a chamber technique. The air-sea-ice CO2 flux ranged from -1.8 to +0.5 mg Cm^[-2] h^[-1] (where negative values indicate a sink for atmospheric CO2). The partial pressure of CO2 (pCO2) in the brine of sea ice was substantially lower than that of the atmosphere, primarily because of the influence of the under-ice plume from the Saromabetsu river located in the southeastern part of the lagoon. This suggests that the brine had the ability to take up atmospheric CO2 into the sea ice. However, the snow deposited over the sea ice and the superimposed ice that formed from snowmelting and refreezing partially blocked CO2 diffusion, acting as an impermeable medium for CO2 transfer. Our results suggest that the air-sea-ice CO2 flux was dependent not only on the difference in pCO2 between the brine and the overlying air, but also on the status of the ice surface. These results provide the necessary evidence for evaluation of the gas exchange processes in ice-covered seas.

Physico-chemical properties in the brine and under-ice water were measured in Saroma-ko Lagoon on the northeastern coast of Hokkaido, Japan, which is connected to the Sea of Okhotsk, during the period from mid-February through mid-March 2006. The brine within brine channels of the sea ice was collected with a new sampling method examined in this study. Salinity, dissolved inorganic carbon (DIC), total alkalinity (TA), dissolved oxygen (DO), nutrients and oxygen isotopic ratio (δ18O) contained in the brine within brine channels of the sea ice and in the under-ice water varied largely in both time and space during the ice melt period, when discharge from Saromabetsu River located on the southeast of the lagoon increased markedly due to the onset of snow melting. The under-ice plume expands as far as 4.5 km from the river mouth at mid-March 2006, transporting chemical components supplied from the river into the lagoon. The under-ice river water was likely transported into the sea ice through well-developed brine channels in the sea ice due to upward flushing of water through brine channels occurred by loading of snowfalls deposited over the sea ice. These results suggest that the river water plume plays an important role in supplying chemical components into the sea ice, which may be a key process influencing the biogeochemical cycle in the seasonally ice-covered Saroma-ko Lagoon.

第4回極域科学シンポジウム個別セッション：[OM] 気水圏11月15日（金） 国立極地研究所 ３階ラウンジ

第4回極域科学シンポジウム横断セッション：[IA] 「急変する北極気候システム及びその全球的な影響の総合的解明」―GRENE北極気候変動研究事業研究成果報告2013―11月12日（火） 国立極地研究所 ２階大会議室

第3回極域科学シンポジウム/特別セッション「これからの北極研究」11月28日（水） 国立極地研究所 2階大会議室

In order to ascertain yearly variability, the pCO2 in the air and surface sea water was measured during the winter season in and over the western North Pacific from 1981 to 1985, and δ13C measurements were taken from 1982. The seasonality was also studied in the area off Japan's coast. The distribution of pC02 in the surface sea water was found to vary with geographical location; it is low in the mid-latitudes and high in the equatorial region. During the El Niño Event in 1982/1983, the horizontal distribution of pCO2 was greatly disturbed, with a relatively low temperature and a high pC02 level in the equatorial region in the western North Pacific. Surface sea water in the temperate zone shows a seasonal variation in pCO2, which is low in winter and high in summer. It was found that pC02 in the air over the ocean decreases with distance from the Japanese islands, and south of 15°N it is nearly constant. Between 1982 and 1985, the δ13C of CO2 in the air south of 15°N decreased at 0.022 ± 0.006‰, yr-1 and the pCO2 increased at 1.11 ± 0.04 ppm yr-1. The secular variation of pCO2 and δ13C in the surface sea water with the CO2 increase in the air, was not ascertainable from observations from 1981 to 1985.DOI: 10.1111/j.1600-0889.1987.tb00285.x

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月17日（木） 統計数理研究所 セミナー室2

Recent changes in oceanic CO2 partial pressure (pCO2^[sea]) have attracted increasing interest as they relate to the increase in atmospheric CO2 and climate change. We report decadal changes in the growth rates of pCO2^[sea] in latitudinal zones from 3°N to 33°N along the repeat hydrographic line at 137°E in the western North Pacific in winter. The growth rates of pCO2^[sea] for 1999-2009 (-0.3 ± 0.9 [mean ± 1σ] to 1.7 ± 0.5 μatm yr^[-1]) were lower than those for 1984-1997 (0.7 ± 0.3 to 2.2 ± 0.6 μatm yr^[-1]) at most latitudes, indicative of the recent notable deceleration of pCO2^[sea] increase. For latitudes around 10-20°N, we attribute the reduction in the growth rate of pCO2^[sea] for 1999-2009 primarily to the reduction in the contribution from dissolved inorganic carbon (DIC) originating from a reduction in carbon accumulation associated with the expansion of the western Subtropical Gyre towards the south.

An edited version of this paper was published by AGU. Copyright (2005) American Geophysical Union., The long-term trend of the partial pressure of CO2 in surface seawater (pCO2sea) in late-January to early-February during the past two decades was examined in the western North Pacific along the repeat line at 137°E from 3°N to 34°N. The growth rate of pCO2 sea at each 1º in latitude ranged from +1.3 ± 0.2 to +2.1 ± 0.3 μatm yr-1, and the average was +1.7 ± 0.2 μatm yr-1. The growth of pCO2 sea is attributable mainly to the uptake of anthropogenic CO2 in surface water and, to a small extent, to the regional changes in sea surface temperature (SST). The net air-to-sea CO2 flux in January–February that accounts for 40 to 60% of the annual flux remained at a similar level in the subtropical regions (7ºN to 34ºN). In the equatorial region (3ºN to 6ºN), however, a slight increase in the CO2 efflux was seen.

DOI: 10.1034/j.1600-0889.2003.00008.x

The rates of the addition of methoxide ion to the CN bond and the proton/deuteron transfer reactions between methoxide ion and substituted phenylacetonitriles (XC_6H_4CY_1Y_2 CN: X=CH_3O, CH_3, Cl, Y_1=H, D, Y_2=H, D; X=H, Y_1=CH_3, Y_2=H, D) have been determined at high pressures, The rate constant at each pressure is fitted to the previously derived formula which permits the distinction between the structural volume change and the electrostatic volume change. The activation volume varies with the substituent from -(9.5±2.5) to -(13.7±1.8)cm^3/mol for the iminoether formation, and from +(18.2±2.9) to +(7.7±2.7) cm^3/mol for the deuteron transfer. The activation volume of the proton transfer reaction coincides with the value of the deuteron transfer reaction within experimental error. In the iminoether formation, the activation volume is more contributed from the structural term which does not vary so much with the substituent than the electrostatic one. And volume profile for that reaction suggests a product-like transition state. On the other hand, in the deuteron transfer reaction, the electrostatic term which varies considerably with the substituents, contributes to the activation volume much mare than the covalent one. It is also suggested from the fractionation theory that the solvation number does not change remarkably with pressure.

The rates of the nucleophilic attack of methoxide ion to phenylacetonitrile in methanol were studied at high pressure. The attack resulted in two different types of reactions, one being the elimination of α-hydrogens while the other the base-catalyzed methanol addition to C≡N triple bond. Positive (+24cm^3 mol^-1 at 303.2K)and negative(-13.1cm^3 mol^-1 at 313.2K) activation volume changes were observed for the deuterium elimination and the nucleophilic attack of methoxide ion to C≡N triple bond, respectively. An expression which permits the distinction between the electrostatic volume change and the covalent volume change has been derived from a perturbed molecular-orbital theory combined with the Owen-Brinkley formula. Validity of the expression has been tested for various types of high-pressure reactions including those here studied.

The effects of pressure on the reaction of malononitrile have been studied in water, methanol, ethanol, iso-propanol, dioxane, and so on in the temperature range of 323 to 343 K up to 8000 kg cm^-2. The reaction produced a dimer and two trimers only at high pressure. The dimer was identified as 1, 1, 3-tricyano-2-amino-1-propene and the trimers as 2, 4-diamino-3, 5-dicyano-6-cyanomethylpyridine, and ammonium 1, 1, 3, 3-tetracyano-2-cyanomethylpropenide, which are, respectively, the "Trimer 1" and "Trimer 2" reported by Schenck and Finken. The "Trimer 3" was not yielded.1. 3, 5-Tricyanomethyl-s-triazine was not produced in the present reaction either. The polar solvents and the addition of triethylamine increased the reaction rate remarkably. The formation of the dimer is autocatalytic and its mechanism is found to be a Thorpe-type reaction.

The ionic dissociation constans of ionization of triethylamine in methanol were determined from the measurements of electrical conductivities over the range of 1-2000kg cm^-2 at 25℃ and 1-1600kg cm^-2 at 30 and 40℃. The ionization constants were obtained by the Shedlovsky equation which contains the equivalent conductivity of weak electrolyte and the limiting equivalent conductivity of strong electrolyte. The data were treated by the Fuoss-Onsager equation for potassium chloride, triethylammonium chloride, and potassium methoxide to determine the limiting equivalent conductivities after the justification of the Onsager limiting equation at high pressure. The ionic dissociation constant at 25℃ increased from 0.502×10^-6 mol kg^-1 at 1 atm to 5.78×10^-6 mol kg^-1 at 2000kg cm^-2, and decreased with temperature to 0.264×10^-6 mol kg^-1 at 1 atm and 40℃. The pressure dependence of ionization constant was quantitatively explained by the change of dielectric constant with pressure, and the electrostrictive volume change, and the other volume changes (crystal, void volume change et al.) at 1 atm. It was found that both the electrostrictive volume change and the other volume changes play an important role for the pressure effects on the ionization in methanol.

The north-south section of the atmospheric concentration of ^(Kr) over the Pacific is first reported. The most striking feature of the section is a large concentration difference at the geographical position of the intertropical convergence. The ^(Kr) concentration in the air over the North Pacific ranged from 22 to 23pCi m^ and in the South Pacific 16pCi m^. The concentration differences between two hemispheres is about 6pCi m^. Five year records from land stations in Japan indicate that the annual increase is about 1pCi m^y^. It seems that the amount of the southward transport of ^(Kr) from the northern hemisphere is nearly equilibrated with that of radioactive disintegration and/or dissolution of ^(Kr) into the ocean in the southern hemisphere.

Distribution of pCO_2 and δ^C in the air over the ocean and in the surface sea water of the Southern Ocean was determined during the cruise of BIOMASS (November 1983 to February 1984). In the study area, south of Australia, pCO_2 in the air was nearly constant (∿342ppm) throughout the cruise but pCO_2 in the surface sea water varied considerably ranging from 300 to 356ppm. In general, pCO_2 in the surface sea water tended to increase from north to south, and it was relatively higher than that in the air in higher latitudes. The average value in the south of 5°S was -7.97‰ for δ^C and 341.7ppm for pCO_2 of atmospheric CO_2. These results indicate that atmospheric CO_2 over the ocean is not isotopic equilibrium with the surface sea water and kinetic fractionation must be considered for understanding δ^C of atmospheric CO_2.