Fast Oxidation Reaction of Nitrite by Dissolved Oxygen in the Freezing Process in the Tropospheric Aqueous Phase     

Norimichi Takenaka  Tohru Daimon  Akihiro Ueda  Keiichi Sato  Masaru Kitano  Hiroshi Bandow  Yasuaki Maeda 《Journal of Atmospheric Chemistry》1998,29(2):135-150

Nitrite oxidation in the tropospheric aqueous phase by freezing was evaluated by freezing a field sample. Nitrite oxidation by dissolved oxygen in the freezing process is much faster than by other oxidation processes, such as reactions with ozone, hydrogen peroxide or dissolved oxygen in an aqueous solution at pHs 3 to –6. At pH 4.5 and 25°C, the lifetime of nitrite in the aqueous phase is ca. 1 hr in oxidation by ozone (6×10^-10 mol dm^-3), ca. 10 hr in oxidation by H₂O₂ (2×10^-4 mol dm^-3), and 7.5 hr (Fischer and Warneck, 1996) in photodissociation at midday in summer. Under the same conditions at a temperature below 0°C, the lifetime of nitrite in the freezing process is estimated as ca. 2 sec when the droplets are frozen within a second. The reaction by freezing is affected by the presence of salts, such as NaCl or KCl, or orgnaic compounds, such as methanol or acetone. The results of freezing a field rain or fog sample showed that nitrite oxidation proceeds below pH 6, and the conversion ratio of nitrate from nitrite increases with decreasing pH. The oxidation of nitrite by freezing was also observed in freezing fog particles generated by an ultrasonic humidifier. The ratios of the concentrations of ions in the winter sample to those in the summer sample (or those in the fog sample) were almost the same values. However, the concentration of nitrite in the winter sample was lower than that estimated by the ratios of other ions. From the present study, it seems that the freezing process plays an important role in the nitrite sink process in the tropospheric aqueous phase.  相似文献   

Frequency-dependent Attenuation of High-frequency P and S Waves in the Upper Crust in Western Nagano, Japan     

K. Yoshimoto  H. Sato  Y. Iio  H. Ito  T. Ohminato  M Ohtake 《Pure and Applied Geophysics》1998,153(2-4):489-502

—Borehole seismograms from local earthquakes in the aftershock region of the 1984 western Nagano Prefecture, Japan earthquake were analyzed to measure the frequency-dependent characteristics of P- and S-wave attenuation in the upper crust. The records from a three-component velocity seismometer at the depth of 145m exhibit high S/N-ratio in a wide frequency range up to 100 Hz. Extended coda normalization methods were applied to bandpass-filtered seismograms of frequencies from 25 to 102 Hz. For the attenuation of high-frequency P and S waves, our measurements show Q _P ^-1? 0.052?^-0.66 and Q _S ^-1? 0.0034?^-0.12 respectively. The frequency dependence of the quality factor of S waves is very weak as compared with that of P waves. The ratio of Q _P ^-1/Q _S ^-1 is larger than unity in the entire analyzed frequency range.  相似文献   

A new technique for measuring diffusion coefficients of cations and anions in ionic crystals     

Hiroki Sato  Yoshiaki Ida 《Physics of the Earth and Planetary Interiors》1981,25(4):396-405

A new technique has been developed for measuring the diffusion coefficient in ionic crystals. Based on Einstein's formula expressing the relation between diffusion coefficient and electric mobility, the electrical impedance of a diatomic ionic crystal is derived theoretically as a function of frequency of the applied electric field. In this method, the diffusion coefficients of both cations and anions are determined simultaneously by fitting the measured impedance to the theoretical relation. This method was applied to NaCl single crystals in the temperature range 370–780°C. The impedance was determined over the frequency range 0.01 Hz to 1 kHz, at constant temperature. The diffusion coefficients thus obtained for NaCl agree reasonably well with previous data by means of a radioactive isotope technique. The activation energies for Na⁺ and Cl^? obtained are 1.97±0.03 eV and 2.08±0.06 eV, respectively, in the intrinsic region, and 0.92±0.02 eV and 1.06±0.02 eV in the extrinsic region. It was discovered that there are diffusion blocks of approximately 2 μm width, which obstruct free migration of ions in a single crystal.  相似文献   

Multivariate correlation analysis of suspended-sediment characteristics     

Satoshi Yamamoto 《Mathematical Geology》1976,8(1):57-74

Principal component analysis (PCA) was employed to investigate interrelationships among various characteristics of seawater and suspended sediments obtained from surface waters of two Asian marginal seas. On the basis of multivariate correlation analysis for the two marginal seas combined, three important factors were extracted and interpreted: (1) current-energy conditions, (2) the influence of rivers, and (3) biochemical conditions of seawater. A relationship between anisotropic mineral grains and combustible organic matter is suggested by the fact that suspended sediment, containing coarser anisotropic mineral grains, also contains larger amounts of combustible organic matter.  相似文献   

Local effects on tidal strain measurements at Esashi, Japan     

T. Sato  J. C. Harrison 《Geophysical Journal International》1990,102(3):513-526

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Sex‐related differences in size,function and regeneration of the major cheliped in the hermit crab Pagurus filholi          下载免费PDF全文

Kento Matsuo  Daisuke Tanikawa  Chiaki I. Yasuda  Satoshi Wada 《Marine Ecology》2015,36(4):1391-1399

Pagurus hermit crabs have a well‐developed right cheliped (major cheliped) and in some species the major cheliped of males is longer than that of females. This paper describes sex‐related differences in major cheliped length and regeneration pattern of the major cheliped in the hermit crab Pagurus filholi. We also examined the function of the major cheliped in male–male competition. Major cheliped length of males was longer than that of females in P. filholi. Males regenerated larger chelipeds than females at the first molt after experimentally induced autotomy. Body size growth in males of the regeneration group was less than that in intact males of the control group while there was no significant difference in body size growth of females between regeneration and control groups. Major cheliped length was included in the best model to explain the outcome of male–male competition and thus sexual selection appears to be a causative factor in the sex‐related difference of the major cheliped length. Sex‐related differences in the regeneration pattern may reflect differences in evolutionary pressures on males for large major chelipeds and females for large body size.  相似文献   

Distribution of <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> in the southwestern Sea of Japan related to meandering of the Tsushima Warm Current     

Satoshi?KitajimaEmail author  Naoki?Iguchi  Naoto?Honda  Tatsuro?Watanabe  Osamu?Katoh 《Journal of Oceanography》2015,71(3):287-296

We investigated the horizontal distribution of Nemopilema nomurai medusae using a midwater trawl in the southwestern Sea of Japan from September to October of each year from 2006 to 2012. Numerous medusae of this species found in 2006, 2007, and 2009 were mainly distributed far (>40 km) from the mainland of Japan in the western part of the survey area, but were distributed in the stations closest (<25 km) to the mainland in the eastern part, particularly in 2006 and 2009. These distribution patterns were associated with the path of the second branch of the Tsushima Warm Current (TWC) that flows offshore to the west of Oki Islands and usually approaches the mainland of Japan to the east of Oki Islands. Differences in jellyfish distribution across the survey periods were related to the distribution of the second branch being associated with types, position and intensity of eddies in the eastern part of the survey area. Hence, the formations of eddies and consequent variation in the path of the TWC would be responsible for transporting medusae from offshore to near the mainland to the east of Oki Islands. Individuals with large bells accumulated in the northwestern part of the survey area, where a cyclonic eddy was present downstream of the third branch of the TWC. This variation in bell size distribution may be ascribed to differences in the physical and/or biological factors among the three branches of the TWC.  相似文献   

Long-term evolution of the aerosol debris cloud produced by the 2009 impact on Jupiter     

A. Sánchez-Lavega  G.S. Orton  R. Hueso  L.N. Fletcher  E. García-Melendo  I. de Pater  H.B. Hammel  A. Simon-Miller  F. Marchis  O. Mousis  J. García-Rojas  M. Cecconi  K. Noll  S. Pedraz  P. Kalas  W. Golisch  P. Sears  V. Reddy  R. Binzel  W. Grundy  J. Emery  A. Rivkin  C. Thomas  D. Trilling  K. Bjorkman  A.J. Burgasser  H. Campins  T.M. Sato  Y. Kasaba  J. Ziffer  R. Mirzoyan  H. Bouy 《Icarus》2011,214(2):462-476

We present a study of the long-term evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object on 19 July 2009 (Sánchez-Lavega, A. et al. [2010]. Astrophys. J. 715, L155-L159). The work is based on images obtained during 5 months from the impact to 31 December 2009 taken in visible continuum wavelengths and from 20 July 2009 to 28 May 2010 taken in near-infrared deep hydrogen-methane absorption bands at 2.1-2.3 μm. The impact cloud expanded zonally from ∼5000 km (July 19) to 225,000 km (29 October, about 180° in longitude), remaining meridionally localized within a latitude band from 53.5°S to 61.5°S planetographic latitude. During the first two months after its formation the site showed heterogeneous structure with 500-1000 km sized embedded spots. Later the reflectivity of the debris field became more homogeneous due to clump mergers. The cloud was mainly dispersed in longitude by the dominant zonal winds and their meridional shear, during the initial stages, localized motions may have been induced by thermal perturbation caused by the impact’s energy deposition. The tracking of individual spots within the impact cloud shows that the westward jet at 56.5°S latitude increases its eastward velocity with altitude above the tropopause by 5-10 m s⁻¹. The corresponding vertical wind shear is low, about 1 m s⁻¹ per scale height in agreement with previous thermal wind estimations. We found evidence for discrete localized meridional motions with speeds of 1-2 m s⁻¹. Two numerical models are used to simulate the observed cloud dispersion. One is a pure advection of the aerosols by the winds and their shears. The other uses the EPIC code, a nonlinear calculation of the evolution of the potential vorticity field generated by a heat pulse that simulates the impact. Both models reproduce the observed global structure of the cloud and the dominant zonal dispersion of the aerosols, but not the details of the cloud morphology. The reflectivity of the impact cloud decreased exponentially with a characteristic timescale of 15 days; we can explain this behavior with a radiative transfer model of the cloud optical depth coupled to an advection model of the cloud dispersion by the wind shears. The expected sedimentation time in the stratosphere (altitude levels 5-100 mbar) for the small aerosol particles forming the cloud is 45-200 days, thus aerosols were removed vertically over the long term following their zonal dispersion. No evidence of the cloud was detected 10 months after the impact.  相似文献   

Trans-Equatorial Loop System Arising from Coronal Hole Boundaries through Interactions between Active Regions and Coronal Holes     

Masaki Yokoyama  Satoshi Masuda 《Solar physics》2010,263(1-2):135-152

It is not clear how trans-equatorial loop systems (TLSs) are formed, although they have been observed often with Yohkoh/SXT. We focus here on a TLS that appeared on 27 May 1998. Yokoyama and Masuda (Solar Phys. 254, 285, 2009) proposed a new scenario for the formation mechanism of the TLS. In this scenario, they pointed out the importance of magnetic interaction between an active region and a coronal hole to make “strong-seed magnetic fields” before a transient (bright and short-lived) trans-equatorial loop was created. The main aims of this study are to verify the scenario and to make the TLS formation mechanism clear, based on observational data. Yohkoh/SXT images, SOHO/MDI magnetograph data, and Kitt Peak coronal-hole maps were mainly used for our analyses. We investigated the TLS in detail from the time that there were no signatures of the TLS to its clear appearance. The following results are obtained: i) an active region emerged in the vicinity of a coronal-hole boundary, ii) the coronal-hole boundary retreated during the period when the active region was developing, iii) temporal variations of soft X-ray intensities were roughly synchronized between the coronal-hole boundary and a trans-equatorial region, and iv) new closed loops were observed in soft X-rays clearly at the coronal-hole boundary. Since i), ii), iii), and iv) are just what we expect in the scenario of YM2009, the scenario found support. We conclude that the TLS was originating with large-scale magnetic fields of the coronal-hole boundary through magnetic reconnection between the active region and a coronal hole.  相似文献   

Differences in abundance and distribution of Alexandrium cysts in Sendai Bay,northern Japan,before and after the tsunami caused by the Great East Japan Earthquake     

Takashi Kamiyama  Hiroyuki Yamauchi  Satoshi Nagai  Mineo Yamaguchi 《Journal of Oceanography》2014,70(2):185-195

The tsunami caused by the Great East Japan Earthquake on 11 March 2011 greatly influenced the coastal benthic environment on the northern Pacific coast of Japan. We used the direct count method to investigate changes in the abundance and distribution of Alexandrium (Alexandrium tamarense and Alexandrium catenella) cysts before and after the tsunami in Sendai Bay. Densities of Alexandrium cysts in sediments collected in summer 2011 ranged from 0 to 8,190 cysts cm^?3. In the western part of the bay, the density increased greatly after the tsunami, the highest density being approximately 10 times the density recorded in 2005. Molecular identification of single cysts with multiplex polymerase chain reaction (PCR) showed that Alexandrium tamarense dominated the cyst population in the southwestern part of the bay in 2011. Furthermore, accumulation of cysts on the surface sediment after disturbance of the sediment was confirmed by a laboratory experiment. The main factor causing the drastic changes in abundance and distribution of Alexandrium cysts after the earthquake was considered to be vertical and horizontal redistribution of the cysts in sediments after the tsunami.  相似文献