Temperature scaling pattern dependence on representative concentration pathway emission scenarios
A letter     

Yasuhiro Ishizaki  Hideo Shiogama  Seita Emori  Tokuta Yokohata  Toru Nozawa  Tomoo Ogura  Manabu Abe  Masakazu Yoshimori  Kiyoshi Takahashi 《Climatic change》2012,112(2):535-546

To preserve consistency among developed emission scenarios, the scenarios used in climate modeling, and the climate scenarios available for impact research, the pattern scaling technique is useful technique. The basic assumption of pattern scaling is that the spatial response pattern per 1 K increase in the global mean surface air temperature (SAT) (scaling pattern) is the same among emission scenarios, but this assumption requires further validation. We therefore investigated the dependence of the scaling pattern of the annual mean SAT on GHGs emission scenarios of representative concentration pathways (RCP) and the causes of that dependence using the Model for Interdisciplinary research on Climate 5 developed by Japanese research community. In particular, we focused on the relationships of the dependency with effects of aerosols and Atlantic meridional overturning circulation. We found significant dependencies of the scaling pattern on emission scenarios at middle and high latitudes of the Northern Hemisphere, with differences of >15 % over parts of East Asia, North America, and Europe. Impact researchers should take into account those dependencies that seriously affect their research. The mid-latitude dependence is caused by differences in sulfate aerosol emissions per 1 K increase in the global mean SAT, and the high-latitude dependence is mainly caused by nonlinear responses of sea ice and ocean heat transport to global warming. Long-term trends in land-use and land-cover changes did not significantly affect the scaling pattern of annual mean SAT, but they might have an effect at different timescales.  相似文献   

The contribution of anthropogenic forcings to regional changes in temperature during the last decade     

Nikolaos Christidis  Peter A. Stott  Francis W. Zwiers  Hideo Shiogama  Toru Nozawa 《Climate Dynamics》2012,39(6):1259-1274

Regional distributions of the mean annual temperature in the 2000s are computed with and without the effect of anthropogenic influences on the climate in several sub-continental regions. Simulated global patterns of the temperature response to external forcings are regressed against observations using optimal fingerprinting. The global analysis provides constraints which are then used to construct the regional temperature distributions. A similar approach was also employed in previous work, but here the methodology is extended to examine changes in any region, including areas with a poor observational coverage that were omitted in the earlier study. Two different General Circulation Models (GCMs) are used in the analysis. Anthropogenic forcings are found to have at least quadrupled the likelihood of occurrence of a year warmer than the warmest year since 1900 in 23 out of the 24 regions. The temperature distributions computed with the two models are very similar. While a more detailed assessment of model dependencies remains to be made once additional suitable GCM simulations become available, the present study introduces the statistical methodology and demonstrates its first application. The derived information concerning the effect of human influences on the regional climate is useful for adaptation planning. Moreover, by pre-computing the change in the likelihood of exceeding a temperature threshold over a range of thresholds, this kind of analysis enables a near real-time assessment of the anthropogenic impact on the observed regional temperatures.  相似文献   

Emission scenario dependencies in climate change assessments of the hydrological cycle   总被引：1，自引：1，他引：0  

Hideo Shiogama  Naota Hanasaki  Yuji Masutomi  Tatsuya Nagashima  Tomoo Ogura  Kiyoshi Takahashi  Yasuaki Hijioka  Toshihiko Takemura  Toru Nozawa  Seita Emori 《Climatic change》2010,99(1-2):321-329

Anthropogenic global warming will lead to changes in the global hydrological cycle. The uncertainty in precipitation sensitivity per 1 K of global warming across coupled atmosphere-ocean general circulation models (AOGCMs) has been actively examined. On the other hand, the uncertainty in precipitation sensitivity in different emission scenarios of greenhouse gases (GHGs) and aerosols has received little attention. Here we show a robust emission-scenario dependency (ESD); smaller global precipitation sensitivities occur in higher GHG and aerosol emission scenarios. Although previous studies have applied this ESD to the multi-AOGCM mean, our surprising finding is that current AOGCMs all have the common ESD in the same direction. Different aerosol emissions lead to this ESD. The implications of the ESD of precipitation sensitivity extend far beyond climate analyses. As we show, the ESD potentially propagates into considerable biases in impact assessments of the hydrological cycle via a widely used technique, so-called pattern scaling. Since pattern scaling is essential to conducting parallel analyses across climate, impact, adaptation and mitigation scenarios in the next report from the Intergovernmental Panel on Climate Change, more attention should be paid to the ESD of precipitation sensitivity.  相似文献   

Asymmetric impact of the physiological effect of carbon dioxide on hydrological responses to instantaneous negative and positive CO2 forcing     

Manabu Abe  Hideo Shiogama  Tokuta Yokohata  Seita Emori  Toru Nozawa 《Climate Dynamics》2015,45(7-8):2181-2192

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An overview of decadal climate predictability in a multi-model ensemble by climate model MIROC   总被引：1，自引：1，他引：0  

Yoshimitsu Chikamoto  Masahide Kimoto  Masayoshi Ishii  Takashi Mochizuki  Takashi T. Sakamoto  Hiroaki Tatebe  Yoshiki Komuro  Masahiro Watanabe  Toru Nozawa  Hideo Shiogama  Masato Mori  Sayaka Yasunaka  Yukiko Imada 《Climate Dynamics》2013,40(5-6):1201-1222

Decadal climate predictability is examined in hindcast experiments by a multi-model ensemble using three versions of the coupled atmosphere-ocean model MIROC. In these hindcast experiments, initial conditions are obtained from an anomaly assimilation procedure using the observed oceanic temperature and salinity with prescribed natural and anthropogenic forcings on the basis of the historical data and future emission scenarios in the Intergovernmental Panel of Climate Change. Results of the multi-model ensemble in our hindcast experiments show that predictability of surface air temperature (SAT) anomalies on decadal timescales mostly originates from externally forced variability. Although the predictable component of internally generated variability has considerably smaller SAT variance than that of externally forced variability, ocean subsurface temperature variability has predictive skills over almost a decade, particularly in the North Pacific and the North Atlantic where dominant signals associated with Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation (AMO) are observed. Initialization enhances the predictive skills of AMO and PDO indices and slightly improves those of global mean temperature anomalies. Improvement of these predictive skills in the multi-model ensemble is higher than that in a single-model ensemble.  相似文献   

Wakefieldite‐(Nd), a New Neodymium Vanadate Mineral in the Arase Stratiform Ferromanganese Deposit,Kochi Prefecture,Japan     

Takeru Moriyama  Ritsuro Miyawaki  Kazumi Yokoyama  Satoshi Matsubara  Hideo Hirano  Hiroyasu Murakami  Yasushi Watanabe 《Resource Geology》2011,61(1):101-110

Wakefieldite‐(Nd), NdVO₄, is a new mineral found from the Arase stratiform ferromanganese deposit in Kochi Prefecture, Shikoku Island, Japan. It is the Nd‐dominant analogue of wakefieldite‐(Y) and wakefieldite‐(Ce). The ferromanganese ore specimen mainly consists of hematite and caryopilite, and wakefieldite‐(Nd) is typically enclosed in caryopilite. Wakefieldite‐(Nd) is tetragonal, I4₁/amd, a = 7.338(16) Å, c = 6.509(19) Å, V = 350.5(18) ų, Z = 4. The four strongest lines in the X‐ray diffraction pattern [d(Å), I/I₀, hkl] using a Gandolfi camera are (3.67, 100, 200); (2.74, 51, 112); (4.84, 27, 101) and (1.89, 25, 312). Chemical composition of wakefieldite‐(Nd) are V₂O₃ 35.25, As₂O₃ 0.93, SiO₂ 0.14, MnO 1.45, Fe₂O₃ 0.41, Y₂O₃ 2.87, La₂O₃ 7.61, Ce₂O₃ 7.37, Pr₂O₃ 6.04, Nd₂O₃ 26.79, Sm₂O₃ 4.41, Eu₂O₃ 1.36, Gd₂O₃ 3.41, Tb₂O₃ 0.22, Dy₂O₃ 1.41, Er₂O₃ 0.10, total 99.77 wt.%. The empirical formula is (Nd_0.403La_0.118Ce_0.114Pr_0.093Y_0.064Sm_0.064Mn_0.052Gd_0.048Eu_0.020Dy_0.019Fe_0.013Tb_0.003Er_0.001)_1.012(V_0.981As_0.020Si_0.006)_1.007O₄ on the basis of O = 4. The calculated density is 4.782 g/cm³. Microtexture and co‐existing relationship between wakefieldite‐(Nd) and caryopilite suggest that recrystallization and dehydration of Fe‐ and Mn‐oxyhydroxide led to the generation of hematite, caryopilite, rhodochrosite and wakefieldite‐(Nd) by the metamorphism during the accretion of the host unit of the Arase deposit. Chondrite‐normalized REE pattern of the host ferromanganese ore, which is regarded as oceanic metalliferous sediment in origin, shows negative Ce anomaly. Chemical composition of wakefieldite‐(Nd) reflects Ce‐depleted bulk composition of REE‐enriched ferromanganese ore.  相似文献   

Bayesian approach to smoothing palaeomagnetic data using ABIC     

Hideo Tsunakawa 《Geophysical Journal International》1992,108(3):801-811

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The S pole distribution on magnetic grains in pyroxenite determined by magnetotactic bacteria     

Minoru Funaki  Hideo Sakai  Tadashi Matsunaga  Shigehisa Hirose 《Physics of the Earth and Planetary Interiors》1992,70(3-4):253-260

North-seeking bacteria (NSB) with 1 μm diameters migrate to the S pole only. They were applied to identify the S pole determination on a polished surface of magnetite-rich pyroxenite whose natural remanent magnetization (NRM) intensity was 5.64 × 10⁻³ Am² kg⁻¹. The microscopic observations were performed under dark-field illumination in a controlled magnetic field to 10 μT. The NSB formed clusters on limited areas of magnetite grains and scattered over the whole magnetite grains.

The NRM decreased to 1.02 × 10⁻⁵ Am² kg⁻¹ by alternating field (AF) demagnetization to 60 mT but no clusters appeared, while small populations of the NSB scattered on each grain. These scattered bacteria may gather toward the S pole resulting from magnetic domain walls.

When the sample acquired saturation isothermal remanent magnetization (SIRM) to 1 T, the NSB formed dense clusters at the opposite side to the applied field direction on the many grains as expected. This evidence indicated that the NSB can be useful micro-organisms for the determination of fine magnetic structures. Some grains also had NSB clusters at the edge of the grains toward the field direction or did not exhibit any clusters. The complicated distribution of the clusters (the S poles) may be explained by shape anisotropy of the magnetic grains.  相似文献   

Dynamic compaction properties of bentonite-based materials     

Hiroshi Ito  Hideo Komine 《Engineering Geology》2008,98(3-4):133-143

Dynamic compaction tests of bentonite-based materials (BBMs) with 100, 70 and 50% bentonite contents have been performed using five powdery bentonites with different physicochemical properties to establish the simplified evaluation method for dynamic compaction properties of BBMs. For a given bentonite content and a total compaction energy condition, the maximum dry density, ρ_dmax, and the optimum water content, w_opt, which are well-known indexes of compaction properties, for BBMs were determined according to the type of bentonite used for BBMs. For evaluation of those values of BBMs derived in this study, the plastic limit of BBM, w_pbbm, was defined as the plastic limit that was measured using the sample pulverized to a maximum grain size of less than 425 μm in the case of BBM with sand having a maximum grain size of more than 425 μm and was measured using the powdery bentonite itself in the case of BBM without sand. This study proposed equations for evaluating ρ_dmax and w_opt of BBMs with more than 50% bentonite content under the total compaction energy conditions of 551–2755 kN-m/m³ using w_pbbm. Finally, we related the equations derived in this study to the equation for evaluating hydraulic properties of compacted BBMs proposed in previous work and proposed the preparation method of BBMs with more than 50% bentonite content for constructing BBM buffer by in-situ compaction method.  相似文献   

Emplacement processes of proto-arc basalt in the Izu–Bonin–Mariana arc system     

Yuki Kusano  Osamu Ishizuka  Rosemary Hickey-Vargas  Richard J. Arculus 《Island Arc》2021,30(1):e12401

Ascertaining the emplacement mechanism of oceanic basaltic lavas is important in understanding how ocean floor topography is produced and oceanic plates evolve, particularly during the early stages of crustal development of a supra-subduction zone. A detailed study of the volcanic stratigraphy at International Ocean Discovery Program (IODP) Site U1438 in the Amami Sankaku Basin, west of the Kyushu–Palau Ridge, has revealed the development of lava accretion and ridge topography on the Philippine Sea plate at about 49 Ma. Igneous basement rocks penetrated at Site U1438 are the uppermost 150 m of ~6 km-thick oceanic crust, and comprise, in a downhole direction, sheet flows (12.6 m), lobate sheet flows (61.3 m), pillow lavas (50.7 m), and thin sheet flows (25.3 m). The lowermost sheet flows are intercalated with layers of limestone and epiclastic tuff. Lithofacies analysis reveals that the lowermost sheet flows, limestone, and tuff formed on an axial rise, the pillow lavas were emplaced on a ridge slope, and the lobate sheet flows formed off ridge on an abyssal plain. The lithofacies of the basement basalt corresponds to the upper portions of fast-spreading oceanic crust, suggesting that subduction initiation was associated with intermediate to fast rates of seafloor spreading. The surface sheet flows are olivine–clinopyroxene-phyric basalt and differ from the lower basalt flows that contain phenocrysts of olivine and plagioclase, with or without clinopyroxene. The depleted chrome-spinel composition and olivine–clinopyroxene phenocryst assemblage in the surface sheet flows suggests a slight contribution of water for magma generation not present for the lower basalt flows. Considering the lithological difference between the backarc and forearc oceanic crust in the Izu–Bonin–Mariana arc, with sheet flow dominant in the former, seafloor spreading occurred faster in the later stage of subduction initiation.  相似文献