Unsteady flows in Io’s atmosphere caused by condensation and sublimation during and after eclipse: Numerical study based on a model Boltzmann equation     

Shingo Kosuge  Kazuo Aoki  Takeshi Inoue  David B. Goldstein  Philip L. Varghese 《Icarus》2012,221(2):658-669

The behavior of Io’s atmosphere during and after eclipse is investigated on the basis of kinetic theory. The atmosphere is mainly composed of sulfur dioxide (SO₂) gas, which condenses to or sublimates from the frost of SO₂ on the surface depending on the variation of surface temperature (～90–114 K). The atmosphere may also contain a noncondensable gas, such as sulfur monoxide (SO) or oxygen (O₂), as a minor component. In the present study, an accurate numerical analysis for a model Boltzmann equation by a finite-difference method is performed for a one-dimensional atmosphere, and the detailed structure of unsteady gas flows caused by the phase transition of SO₂ is clarified. For instance, the following scenario is obtained. The condensation of SO₂ on the surface, starting when eclipse begins, gives rise to a downward flow of the atmosphere. The falling atmosphere then bounces upward when colliding with the lower atmosphere but soon falls again. This process of falling and bounce back of the atmosphere repeats during the eclipse, resulting in a temporal oscillation of the macroscopic quantities, such as the velocity and temperature, at a fixed altitude. For a pure SO₂ atmosphere, the amplitude of the oscillation is large because of a fast downward flow, but the oscillation decays rapidly. In contrast, for a mixture, the downward flow is slow because the noncondensable gas adjacent to the surface hinders the condensation of SO₂. The oscillation in this case is weak but lasts much longer than in the case of pure SO₂. The present paper is complementary to the work by Moore et al. (Moore, C.H., Goldstein, D.B., Varghese, P.L., Trafton, L.M., Stewart, B. [2009]. Icarus 201, 585–597) using the direct simulation Monte Carlo (DSMC) method.  相似文献   

Seasonal variation in the Ra/Ra ratio of coastal water within the Sea of Japan: Implications for the origin and circulation patterns of the Tsushima Coastal Branch Current     

M. Inoue  K. Tanaka  H. Kofuji  Y. Nakano  K. Komura 《Marine Chemistry》2007,107(4):559-568

In the current study, low-background γ-spectrometry was employed to determine the ²²⁸Ra/²²⁶Ra activity ratio and ¹³⁷Cs activity of 84 coastal water samples collected at six sites along the main island of Japan (Honshu Island) within the Sea of Japan, including the Tsushima Strait, and two other representative sites on Honshu Island (a Pacific shore and the Tsugaru Strait) at 1-month intervals in 2006.The ²²⁸Ra/²²⁶Ra ratio of coastal waters in the Sea of Japan exhibited similar patterns of seasonal variation, with minimum values during early summer (²²⁸Ra/²²⁶Ra = 0.6–0.8), maximum values during autumn (²²⁸Ra/²²⁶Ra = 1.5–3), and a time lag in their temporal changes ( 2.5 months and over  1300 km distance). However, the 2 other sites represented no clear periodic variation.In contrast to the positive correlation between ¹³⁷Cs activity (0.6–1.7 mBq/L) and salinity (15–35), the ²²⁸Ra/²²⁶Ra ratio of coastal water samples from the Sea of Japan was not observed to correlate with salinity, and the increase in the ²²⁸Ra/²²⁶Ra ratio was not as marked (0.5–1; May–June 2004 and 2005) during the migration along Honshu Island. The input of land-derived water and/or the diffusion of radium from coastal sediments is unlikely to have affected the wide seasonal variation in the ²²⁸Ra/²²⁶Ra ratio observed in these water samples.The seasonal variation in the ²²⁸Ra/²²⁶Ra ratio recorded for the coastal waters of the Sea of Japan is considered to be mainly controlled by the remarkable changes in the mixing ratio of the ²²⁸Ra-poor Kuroshio and the ²²⁸Ra-rich continental shelf waters within the East China Sea (ECS). After passing through the Tsushima Strait, this water mass moves northeast along the coastline of the Sea of Japan as the Tsushima Coastal Branch Current (TCBC).  相似文献   

High-time resolution AMS C data sets for Lake Baikal and Lake Hovsgol sediment cores: Changes in radiocarbon age and sedimentation rates during the transition from the last glacial to the Holocene   总被引：1，自引：1，他引：0  

Takahiro Watanabe  Toshio Nakamura  Fumiko Watanabe Nara  Takeshi Kakegawa  Kazuho Horiuchi  Ryoko Senda  Takefumi Oda  Mitsugu Nishimura  Genki Inoue Matsumoto  Takayoshi Kawai 《Quaternary International》2009,205(1-2):12

High-time resolution ¹⁴C dating of Lake Baikal sediment cores indicates negative and positive anomalies of calculated linear sedimentation rate (LSR; 1.1 and 35.6 cm/ka, respectively) during the period of climate transition from the last glacial to Holocene. The timing of the Lake Baikal apparent LSR anomalies is consistent with that of the changes in the atmospheric radiocarbon concentration (Δ¹⁴C) during Younger Dryas rapid cooling event. ¹⁴C dating of lipids in the Lake Baikal surface sediments revealed that the sources of sedimentary lipids were different in each basin. In the Northern Basin of Lake Baikal, the ¹⁴C age of total lipids from the surface sediment (4.0 ¹⁴C ka) was found to be older than that of TOC (1.6 ¹⁴C ka). By contrast, the ¹⁴C age of total lipids in the Southern Basin was younger than that of the TOC by ca. 0.7–3.0 ka.In the Lake Hovsgol sediment cores, ages of the main lithologic boundaries during the last glacial–interglacial transition were estimated based on new ¹⁴C data sets. TOC concentration in the cores started to rapidly increase at 13.8 ± 0.3 ¹⁴C ka at the base of the basinwide finely laminated layer deposited during Bølling/Allerød. The base of the layer diatomaceous mud corresponds to the end of Younger Dryas event (10.6 ± 0.1 ¹⁴C ka).  相似文献   

Phytoplankton assemblage in the Plio-Pleistocene record of Lake Baikal as indicated by sedimentary steryl chlorin esters     

Yukinori Tani  Fumiko Nara  Yuko Soma  Mitsuyuki Soma  Nobuyasu Itoh  Genki Inoue Matsumoto  Atsushi Tanaka  Takayoshi Kawai 《Quaternary International》2009,205(1-2):126

Past changes in phytoplankton assemblages in Lake Baikal over the last 4.5 Ma, both in population and composition, are inferred from the downcore profiles of the relatively stable chlorophyll derivatives steryl esters of pyropheophorbides a and b (steryl chlorine esters; SCEs) in the 0–200 m section of the BDP-98 drill core, supplemented by the data on biogenic silica (BSi) and total organic carbon (TOC) contents. SCEs-a and -b dominate among sedimentary chlorophyll derivatives in the BDP-98 sediments except for the upper few meters, indicating their high stability during diagenetic alteration of sediments. The depth (age) profiles of SCEs-a are consistent with BSi and TOC profiles and are interpreted as reflecting primary productivity of the lake in the past. Baikal proxies reveal close correlation with marine oxygen isotope records (MIS stratigraphy). These observations confirm that climate change in the northern hemisphere has been a primary factor controlling the total phytoplankton productivity in Lake Baikal during the last several million years.Among SCEs-a, C₃₀ (dinostanol)-SCE-a, a marker of dinoflagellates was identified by GC–MS analysis. SCE-b, a marker of green algae, was identified by its UV–vis spectrum. The ratio of C₃₀-SCE-a to total SCEs-a (TSCEs-a) was higher during 4.5–4.2 and 1.7–1.3 Ma, suggesting that dinoflagellates proliferated preferentially in those periods. The early Pleistocene maximum of this ratio corresponds to the broad minimum of diatom abundance previously suggested to have recorded a prolonged regional cooling. An abrupt increase in the SCE-b/TSCEs-a ratio was observed at 2.5–2.6 Ma, indicating that green algae containing chlorophyll b have proliferated in Lake Baikal during this period. This interval has also been suggested to contain evidence for a significant regional cooling based on minima of diatom abundance and BSi in sediments. The depth profile of C₂₇Δ⁵ (cholesterol)-SCE-a relative to TSCEs-a showed a trend similar to that of BSi, suggesting that C₂₇Δ⁵-SCE-a/TSCEs-a ratio is a potential marker of diatoms in Lake Baikal.Certain mismatches between the Lake Baikal profiles of biological indicators and the marine oxygen isotope records, as well as the slight temporal offsets between different Lake Baikal biological marker signals suggest that the regional component of climatic and/or lacustrine environmental changes also have played a role in determining the composition of the Lake Baikal Plio-Pleistocene phytoplankton assemblage.  相似文献   

Seismological evidence for compositional variations at the base of the mantle transition zone under Japan Islands   总被引：1，自引：1，他引：0  

Akira Yamada  Dapeng Zhao  Toru Inoue  Daisuke Suetsugu  Masayuki Obayashi 《Gondwana Research》2009,16(3-4):482-490

Temperature and water content anomalies just above the 660-km discontinuity under the Japan Islands are estimated from seismological observations. Two sets of seismological observations of P-wave velocity perturbations and depth variations of the 660-km discontinuity are used, which are (1) long-wavelength (~ 500 km) variations from seismic tomography based on a grid parameterization and waveform analysis of ScS reverberations and (2) moderate-wavelength (~ 150 km) variations from seismic tomography with a block parameterization and receiver-function analysis. To estimate temperature and water content anomalies, partial derivatives of velocity and depth variations with respect to temperature and water content determined by mineral physics studies are used. Under Southwest Japan, low temperature and high water-content anomalies are obtained from both sets of seismological observations, which have already been found by a previous study. Under Northeast Japan, however, there are discrepancies between the results estimated from the two data sets, possibly due to the different resolution scales. This discrepancy is dismissed when examining distributions of the temperature and water content anomalies. These anomalies can be grouped into two geographical locations, one group under Southwest Japan, the other under Northeast Japan. The two groups are clearly separated and exhibit common features in both sets of the seismological observations. The grouping is interpreted by a compositional difference between the subducting Pacific slab under Southwest Japan and a normal mantle under Northeast Japan.  相似文献   

Relating food and human hair to assess mercury exposure levels in Poboya,Central Sulawesi,Indonesia     

M. M. Sari  T. Inoue  Y. Matsumoto  K. Yokota 《International Journal of Environmental Science and Technology》2017,14(3):463-472

Poboya is a major small-scale gold-mining area in Central Sulawesi, Indonesia, that has been operating since 2009. About 200–500 kg of mercury is released each day as a result of gold-mining activities over a total area of 7000 ha. We examined mercury contamination by using two types of sample, namely food and human hair. Samples were obtained in Poboya and in the city of Palu, 11 km away. Samples of 22 foods were obtained from traditional markets in Poboya and Palu. Total mercury concentrations ranged from 0.003 to 0.31 µg/g in foods from Poboya and from 0.001 to 0.13 µg/g in those from Palu. The highest total mercury concentration in Poboya was found in unripe banana, which is frequently consumed by the local people. In Poboya, the weekly mercury intakes from foods were calculated at 180.3 µg/person from vegetables, 1.7 µg/person from processed foods, 51.4 µg/person from seafood, and 17.2 µg/person from meat and eggs. In Palu, the weekly mercury intakes were 2.9 µg/person from vegetables, 3.1 µg/person from processed foods, 60.8 µg/person from seafood, and 19 µg/person from meat and eggs. These findings delineated Poboya as an area polluted by mercury contamination. Intake of mercury-contaminated food influenced the results obtained in human hair. Hair concentrations of total mercury in Poboya ranged from 0.3 to 19.6 µg/g.  相似文献   

Slab decarbonation and CO₂ recycling in the Southwestern Colombian volcanic arc     

Maria I. Marín-Cerón  Takuya Moriguti  Akio Makishima  Eizo Nakamura 《Geochimica et cosmochimica acta》2010,74(3):1104-1121

The contribution of subducted carbonate sediments to the genesis of the Southwestern Colombian arc magmas was investigated using a comprehensive petrography and geochemical analysis, including determination of major and trace element contents and Sr, Nd, Hf and Pb isotope compositions. These data have been used to constrain the depth of decarbonation in the subducted slab, indicating that the decarbonation process continues into the sub-arc region, and ultimately becomes negligible in the rear arc. We propose on the basis of multi-isotope approach and mass balance calculations, that the most important mechanism to induce the slab decarbonation is the infiltration of chemically reactive aqueous fluids from the altered oceanic crust, which decreasingly metasomatize the mantle wedge, triggering the formation of isotopically different primary magmas from the volcanic front (VF) with relatively high ¹⁷⁶Hf/¹⁷⁷Hf, high ⁸⁷Sr/⁸⁶Sr, negative values of εNd and lower Pb isotopes compared to the rear arc (RA).The presence of more aqueous fluids at the volcanic front may increase the degree of decarbonation into carbonate-bearing lithologies. Moreover, with increasing pressure and temperature in the subduction system, the decrease in dehydration of the slab, leads to cessation of fluid-induced decarbonation reactions at the rear arc. This development allows the remaining carbonate materials to be recycled into the deep mantle.  相似文献   

Decomposition of kyanite and solubility of Al2O3 in stishovite at high pressure and high temperature conditions     

Xi Liu  Norimasa Nishiyama  Takeshi Sanehira  Toru Inoue  Yuji Higo  Shizue Sakamoto 《Physics and Chemistry of Minerals》2006,33(10):711-721

In order to constrain the high-pressure behavior of kyanite, multi-anvil experiments have been carried out from 15 to 25 GPa, and 1,350 to 2,500°C. Both forward and reversal approaches to phase equilibria were adopted in these experiments. We find that kyanite breaks down to stishovite + corundum at pressures above ∼15 GPa, and stishovite + corundum should be the stable phase assemblage at the pressure–temperature conditions of the transition zone and the uppermost part of the lower mantle of the Earth, in agreement with previous multi-anvil experimental studies and ab initio calculation results, but in disagreement with some of the diamond-anvil cell experimental studies in the literature. The Al₂O₃ solubility in nominally dry stishovite has been tightly bracketed by forward and reversal experiments; it is slightly but consistently reduced by pressure increase. Its response to temperature increase, however, is more complicated: increases at low temperatures, maximizes at around 2,000°C, and perhaps decreases at higher temperatures. Consequently, the Al₂O₃ solubility in dry stishovite at conditions of high temperature–high pressure is very limited.  相似文献   

Estimation of methane emission from whole waste landfill site using correlation between flux and ground temperature   总被引：1，自引：0，他引：1  

Tomonori Ishigaki  Masato Yamada  Masanao Nagamori  Yusaku Ono  Yuzo Inoue 《Environmental Geology》2005,48(7):845-853

A methodology to estimate a methane emission in a waste landfill site was developed. The methane flux at a waste landfill site in summer, autumn, and winter was within the following ranges: from −1.3×10⁻² to 16, from −6.4×10⁻² to 7.5, and from −1.6×10⁻³ to 1.5×10⁻² g-CH₄ m⁻² h⁻¹, respectively. In those seasons, the mean methane emission rate and coefficient of variation were 1.1 g-CH₄ m⁻² h⁻¹ ±290%, 0.57 g-CH₄ m⁻² h⁻¹ ±347%, and 5.4×10⁻² g-CH₄ m⁻² h⁻¹ ±370%, respectively. These results simultaneously showed that fluctuations of methane emission from the landfill surface were both of spatial and temporal variability. In each season, an exponential relationship was observed between the methane flux density and the ground temperature. Total methane emissions were estimated to be 5.7×10⁻², 7.1×10⁻³, and 1.7×10⁻³ g-CH₄ m⁻² h⁻¹ in the summer, autumn, and winter surveys, respectively, using a temperature surrogated-kriging method. The results of this study would improve upon the labor-intensive closed-chamber method, and could be a more practical way to estimate methane emissions from waste landfills.  相似文献   

Oscillatory behavior of monsoon rainfall over Sri Lanka during the late 19th and 20th centuries and its relationships to SSTs in the Indian Ocean and ENSO     

B. A. Malmgren  R. Hullugalla  G. Lindeberg  Y. Inoue  Y. Hayashi  T. Mikami 《Theoretical and Applied Climatology》2007,89(1-2):115-125

Summary In this study, we have analyzed the temporal oscillations of precipitation in meso-scale zones of Sri Lanka to examine potential existence of periodic oscillatory behavior in rainfall. Only a few statistically significant cycles were identified: a 3.5-year cycle in most of central Sri Lanka during the January–March rainfall regime and a cycle of the same length in southwestern Sri Lanka during the October regime. A 2.1-year cycle marks the northeastern parts of Sri Lanka during the December/April contrast rainfall regime. This cycle is shown to be strongly related to Quasi-Biennial Oscillation. October and November rainfall are found to be coupled with ENSO fluctuations, and on average, more than 900 mm more rainfall is observed per month over all stations during El Ni?o than during La Ni?a years. Analysis of relationships between the observed meso-scale rainfall regions and the Sea Surface Temperatures (SSTs) in the Indian Ocean north of the Equator showed that the northern Indian Ocean can be divided into three particular regions based on similarity in the SST fluctuations: (a) a region with cool upwelling water, (b) non upwelling water, and (c) the Indian Ocean Warm Pool. We found that there are no statistically significant relationships between the observed SST regions in the Indian Ocean and the meso-scale precipitation patterns in Sri Lanka.  相似文献