Future projections of Indian Summer Monsoon under multiple RCPs using a high resolution global climate model multiforcing ensemble simulations     

Varghese  Stella Jes  Surendran  Sajani  Rajendran  Kavirajan  Kitoh  Akio 《Climate Dynamics》2020,54(3):1315-1328

Climate Dynamics - Present-day simulations (1983–2003) of a global climate model of 60-km resolution with three deep convection schemes are analysed to find the best scheme for simulation of...  相似文献   

Litterfall of three subtropical mangrove species in the family Rhizophoraceae     

Md. Kamruzzaman  Sahadev Sharma  A. T. M. Rafiqul Hoque  Akio Hagihara 《Journal of Oceanography》2012,68(6):841-850

This study was conducted to evaluate and compare the litterfall dynamics of three mangrove species in the family Rhizophoraceae: Rhizophora stylosa, Kandelia obovata, and Bruguiera gymnorrhiza, in Manko Wetland, Okinawa Island, Japan. Over 3?years, these species showed highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. Litterfall of flowers and fruits peaked in July for R. stylosa, and in August and again in October?CNovember for K. obovata. Litterfall of flower buds, flowers, and propagules occurred throughout the year for B. gymnorrhiza, but was highest in summer. Litterfall of propagules was highest in September and May for R. stylosa and K. obovata, respectively. Kendall??s coefficient of concordance revealed that the monthly changes for leaf, stipule, flower, and fruit litterfalls of all the species were strongly and significantly concordant among the years. The conversion rate of flowers to propagules was 2.3?% in R. stylosa, 5.9?% in K. obovata, and 10.3?% in B. gymnorrhiza. Total annual litterfall in R. stylosa was significantly different from K. obovata and B. gymnorrhiza; however, the latter two species showed no significant differences. Leaves contributed the most to the total litterfall of all three species, and represented 58.4, 54.0, and 50.4?% of the total litterfall for R. stylosa, K. obovata, and B. gymnorrhiza, respectively. Except for branches and flower bud primordia, all other components of litterfall had clear annual cycles for all three species. Rhizophora stylosa and K. obovata showed a negative correlation between leaf production and reproductive organ production, but B. gymnorrhiza tended to increase leaf production with increasing reproductive organ production.  相似文献   

Determination of Ge, As, Se and Te in Silicate Samples Using Isotope Dilution-Internal Standardisation Octopole Reaction Cell ICP-QMS by Normal Sample Nebulisation     

Akio Makishima  Eizo Nakamura 《Geostandards and Geoanalytical Research》2009,33(3):369-384

A method for the determination of Ge, As, Se and Te in silicate samples using isotope dilution-internal standardisation (ID-IS) octopole reaction cell (ORC) ICP-QMS by normal sample nebulisation was developed. The method does not involve either hydride generation or ion exchange. Germanium, Se and Te were determined by isotope dilution (ID), and As was determined by ID-IS. A silicate sample with an added Ge-Se-Te spike was digested with an HF-HNO₃-HBr mixture, dried, re-dissolved with HF and the supernatant liquid was directly aspirated into an ORC-ICP-QMS instrument with He or H₂ gas. No matrix effects were observed down to a dilution factor (DF) of ∼ 70 for Ge, Se and Te and DF of ∼ 1000 for As, which resulted in 3s detection limits in silicates of 2, 1, 0.1 and 4 ng g⁻¹, respectively. Advantages of the method are the simple sample introduction as well as a capability of determining S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by ID-IS-ICP-QMS/SFMS from the same solution. Furthermore, the total sample solution consumption was only 0.253 ml with DF = 2000. Therefore, only a 0.13 mg test portion was required. To demonstrate the applicability of this technique, Ge, As, Se and Te in eight silicate reference materials were determined, as well as S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta in four carbonaceous chondrites.  相似文献   

The 11 March 2011 Tohoku Tsunami Survey in Rikuzentakata and Comparison with Historical Events     

Haijiang Liu  Takenori Shimozono  Tomohiro Takagawa  Akio Okayasu  Hermann M. Fritz  Shinji Sato  Yoshimitsu Tajima 《Pure and Applied Geophysics》2013,170(6-8):1033-1046

On 11 March 2011, a moment magnitude M _w = 9.0 earthquake occurred off the Japan Tohoku coast causing catastrophic damage and loss of human lives. In the immediate aftermath of the earthquake, we conducted the reconnaissance survey in the city of Rikuzentakata, Japan. In comparison with three previous historical tsunamis impacting the same region, the 2011 event presented the largest values with respect to the tsunami height, the inundation area and the inundation distance. A representative tsunami height of 15 m was recorded in Rikuzentakata, with increased heights of 20 m around rocky headlands. In terms of the inundation area, the 2011 Tohoku tsunami exceeded by almost 2.6 times the area flooded by the 1960 Chilean tsunami, which ranks second among the four events compared. The maximum tsunami inundation distance was 8.1 km along the Kesen River, exceeding the 1933 Showa and 1960 Chilean tsunami inundations by factors of 6.2 and 2.7, respectively. The overland tsunami inundation distance was less than 2 km. The tsunami inundation height linearly decreased along the Kesen River at a rate of approximately 1 m/km. Nevertheless, the measured inland tsunami heights exhibit significant variations on local and regional scales. A designated “tsunami control forest” planted with a cross-shore width of about 200 m along a 2 km stretch of Rikuzentakata coastline was completely overrun and failed to protect the local community during this extreme event. Similarly, many designated tsunami shelters were too low and were overwashed by tsunami waves, thereby failing to provide shelter for evacuees—a risk that had been underestimated.  相似文献   

Diagnostic metrics for evaluation of annual and diurnal cycles   总被引：1，自引：0，他引：1  

Bin Wang  Hyung-Jin Kim  Kazuyoshi Kikuchi  Akio Kitoh 《Climate Dynamics》2011,37(5-6):941-955

Two sets of diagnostic metrics are proposed for evaluation of global models?? simulation of annual and diurnal cycles of precipitation. The metrics for the annual variation include the annual mean, the solstice and equinoctial asymmetric modes of the annual cycle (AC), and the global monsoon precipitation domain and intensity. The metrics for the diurnal variation include the diurnal range, the land?Csea contrast and transition modes of the diurnal cycle (DC), and the diurnal peak propagation in coastal regions. The proposed modes for the AC and DC represent faithfully the first two leading empirical orthogonal functions and explain, respectively, 82% of the total annual variance and 87% of the total diurnal variance over the globe between 45°S and 45°N. The simulated AC and DC by the 20-km-mesh MRI/JMA atmospheric general circulation model (AGCM) are in a wide-ranging agreement with observations; the model considerably outperforms any individual AMIP II GCMs and has comparable performance to 12-AMIP II model ensemble simulation measured by Pearson??s pattern correlation coefficient. Comparison of four versions of the MRI/JMA AGCM with increasing resolution (180, 120, 60, and 20?km) reveals that the 20-km version reproduces the most realistic annual and diurnal cycles. However, the improved performance is not a linear function of the resolution. Marked improvement of the simulated DC (AC) occurs at the resolution of 60?km (20?km). The results suggest that better represented parameterizations that are adequately tuned to increased resolutions may improve models?? simulation on the forced responses. The common deficiency in representing the monsoon domains suggests the models having difficulty in replicating annual march of the Subtropical Highs that is largely driven by prominent east-west land?Cocean thermal contrast. Note that the 20-km model reproduces realistic diurnal cycle, but fails to capture realistic Madden-Julian Oscillation.  相似文献   

Pressure and temperature dependence of the viscosity of a NaAlSi<Subscript>2</Subscript>O<Subscript>6</Subscript> melt     

Akio Suzuki  Eiji Ohtani  Hidenori Terasaki  Keisuke Nishida  Hiromi Hayashi  Tatsuya Sakamaki  Yuki Shibazaki  Takumi Kikegawa 《Physics and Chemistry of Minerals》2011,38(1):59-64

The viscosity of a silicate melt of composition NaAlSi₂O₆ was measured at pressures from 1.6 to 5.5 GPa and at temperatures from 1,350 to 1,880°C. We employed in situ falling sphere viscometry using X-ray radiography. We found that the viscosity of the NaAlSi₂O₆ melt decreased with increasing pressure up to 2 GPa. The pressure dependence of viscosity is diminished above 2 GPa. By using the relationship between the logarithm of viscosity and the reciprocal temperature, the activation energies for viscous flow were calculated to be 3.7 ± 0.4 × 10² and 3.7 ± 0.5 × 10² kJ/mol at 2.2 and 2.9 GPa, respectively.  相似文献   

Determination of Molybdenum, Antimony and Tungsten at sub μg g⁻¹ Levels in Geological Materials by ID-FI-ICP-MS     

Akio Makishima  Eizo Nakamura 《Geostandards and Geoanalytical Research》1999,23(2):137-148

We have developed a rapid and accurate method for the determination of Mo, Sb and W in geological samples using isotope dilution inductively coupled plasma-mass spectrometry with a flow injection system (ID-FI-ICP-MS). The chemical procedure requires HF digestion of the sample with a Mo-Sb-W mixed spike, subsequent evaporation and dissolution of Mo, Sb and W from Mg and Ca fluorides with HF. Recovery yields of Mo, Sb and W in the extraction were > 94% for samples of peridotite, basalt and andesite composition, with the exception of W in samples of peridotite composition for which recovery was 81%. No matrix effects were observed in the determination of the isotope ratios of Mo, Sb and W in solutions prepared from peridotite, basalt and andesite samples down to a dilution factor of 100. Detection limits of Mo, Sb and W in silicate materials were at the several ng g⁻¹ level. Analysis of the silicate reference materials PCC-1, DTS-1, BCR-1, BHVO-1, AGV-1 from the US Geological Survey and JP-1, JB-1, -2, -3, JA-1, -2, and -3 from the Geological Survey of Japan as well as the Smithsonian reference Allende powder yielded reliable Mo, Sb and W concentrations. The repeatability in the analysis of basalts and andesites was < 9%. This technique requires only 0.2 ml sample solution, and is therefore suitable for analyzing small and/or precious samples such as meteorites, mantle peridotites and their mineral separates.  相似文献   

Determination of Zirconium, Niobium, Hafnium and Tantalum at ng g-1 Levels in Geological Materials by Direct Nebulisation of Sample HF Solution into FI-ICP-MS     

Akio Makishima  Eizo Nakamura  Toshio Nakano 《Geostandards and Geoanalytical Research》1999,23(1):7-20

We have developed a rapid and accurate method to determine Zr, Nb, Hf and Ta (denoted as HFSE) in geological samples by inductively coupled plasma-mass spectrometry fitted with a flow injection system (FI-ICP-MS). The method involves sample decomposition by HF followed by HF dissolution of HFSE coprecipitated with insoluble M and Ca fluoride residues formed during the initial HF attack. This HF solution was directly nebulized into an ICP mass spectrometer. An external calibration curve method and an isotope dilution method (ID) were applied for the determination of Nb and Ta, and of Zr and Hf, respectively. Recovery yields of HFSE were > 96% for peridotite, basalt and andesite compositions, apart from Zr and Hf for peridotite (> 85%). No matrix effects for either signal intensities of HFSE or isotope ratios of Zr and Hf were observed in basalt, andesite and peridotite solutions down to a dilution factor of 100. Detection limits in silicate rocks were 40, 2, 1 and 0.1 ng g-1 for Zr, Nb, Hf and Ta, respectively. This technique required only 0.1 ml of sample solution, and thus is suitable for analysing small and/or precious samples such as meteorites, mantle peridotites and their mineral separates. We also present newly determined data for the Zr, Nb, Hf and Ta concentrations in USGS silicate reference materials DTS-1, PCC-1, BCR-1, BHVO-1 and AGV-1, GSJ reference materials JB-1, -2, -3, JA-1, -2 and -3, and the Smithsonian reference Allende powder.  相似文献   

Upper Mantle Velocity Structure Estimated From Ps-Converted Wave Beneath the North-Eastern Japan Arc   总被引：2，自引：0，他引：2  

Toru Matsuzawa  Norihito Umino  Akira Hasegawa  Akio Takagi 《Geophysical Journal International》1986,86(3):767-787

Summary. The upper boundary of the descending oceanic plate is located by using PS -waves (converted from P to S at the boundary) in the Tohoku District, the north-eastern part of Honshu, Japan. the observed PS-P time data are well explained by a two-layered oceanic plate model composed of a thin low-velocity upper layer whose thickness is less than 10 km and a thick high-velocity lower layer; the upper and lower layers respectively have 6 per cent lower and 6 per cent higher velocity than the overriding mantle. the estimated location of the upper boundary is just above the upper seismic plane of the double-planed deep seismic zone. This result indicates that events in the upper seismic plane, at least in the depth range from 60 to 150 km, occur within the thin low-velocity layer on the surface of the oceanic plate.  相似文献   

Asian monsoon climate change - Understanding and prediction     

Kyung-Ja Ha  June-Yi Lee  Bin Wang  Shang-Ping Xie  Akio Kitoh 《Asia-Pacific Journal of Atmospheric Sciences》2017,53(2):179-180

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