Language：Japanese   Book type：Scholarly book

コアの歴史と地球磁場変動の関連の解説

Responsible for pages：pp.63-77 本全体の編者は春日直樹（一橋大学）。本全体としては１７名の著者による。   Language：Japanese   Book type：Scholarly book

Connecting Science and Culture: Analogical Thinking (Naoki Kasuga, ed.) Chapter 3 "Analogy as inference through similar phenomena -- an example in a scientific research on the modelling of the Earth's inner core anisotropy" (Shigeo Yoshida and Hisashi Nakao)

Event date： 2024.6

Language：English   Presentation type：Poster presentation  

Venue：Great Barrington MA   Country：United States  

Event date： 2024.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kobe International Conference Center, Kobe   Country：Japan  

Event date： 2024.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Makuhari Messe, Chiba   Country：Japan  

Event date： 2023.10

Language：Japanese  

Venue：広島県広島市⽂化交流会館・JMSアステールプラザ   Country：Japan  

マントル対流計算を⽬指した弱圧縮性SPH法の開発
Development of a weakly compressible SPH method aiming at simulating mantle convection

Event date： 2022.5 - 2022.6

Language：Japanese  

Venue：千葉県千葉市幕張メッセ・オンラインハイブリッド   Country：Japan  

導入: 惑星形成過程において集積過程と分化過程の両者を同時に解くような流体シミュレーション手法は確立されていない．特に分化プロセス(もしくは惑星コア形成過程)を数値流体計算によってグローバルに解いた例は少ない．
　集積プロセスのシミュレーションには，一般にSPH法(Smoothed Particle Hydrodynamics method)という手法が広く用いられる[e.g., Benz et al., 1986; Nakajima et al., 2021]．そこで，集積問題で一定のコンセンサスを得ている手法を惑星コア形成問題に応用できないだろうか，と考えた．しかし，従来のSPH法(the Standard SPH method, SSPH法)では物質境界を上手く扱えないという大きな問題があった[Agertz et al., 2007]．この問題に対して，Saitoh and Makino (2013)やHosono et al. (2013)で初めて提案された，密度に依存しないSPH法(the Density-Independent SPH method, DISPH法)は非常に有効な手法である．一方で，この新しい手法を用いた流体数値計算例は少なく[Hosono et al., 2016; Takeyama et al., 2017; Hosono et al., 2019]，境界設定や熱力学量の定式化は，コアマントル分離を扱う目的では使いやすい形に書かれていない．
　本研究では惑星進化(特に惑星コア形成過程)を扱うためにDISPH法の改良を試みる．本研究の目的は，先行研究[e.g., Saitoh and Makino, 2013; Hosono et al., 2013]で明らかにされていない問題点に触れ，その改良方法を提案するものである．

方法: SPH法の基本的な概念は「場の物理量を，近傍粒子を用いなめらかな関数を使って平滑化する」というものである．しかし，従来のSPH法(SSPH法)では密度を平滑化することが理由で，物質境界付近で非物理的な現象が生じる．この解決法としてSaitoh and Makino (2013)が開発した，DISPH法は非常に有効である．一方で，オリジナルのDISPH法をコアマントル分離の問題に応用するには工夫が必要である．例えば， (1)熱力学量の時間発展式を使いやすい形に変形すること (2)境界条件の取り扱い方を工夫すること などである．特に後者は重要である．その理由は，SSPH法では境界の取り扱い方が計算精度に大きく影響を与えることが知られていて[e.g. Bonet and Kulasegaram, 2002; Shao et al., 2012]，DISPH法でも同様であると期待されるからである．そこで，これらの改良を試みた．具体的には，(1)惑星内部を記述するのに適切なDISPH法の基礎方程式を構築し， (2)SSPH法で用いられる境界処理法の一つをDISPH法に応用した[Marrone et al., 2011; Asai et al., 2013]．さらに，DISPH法における自由表面の新しい取り扱い方を提案する．
　これらの改良点を加えたDISPH法を用いて，二次元レイリーテーラー不安定の問題を解いた．つまり，上側に重い液体金属を，下側に軽い液体シリケイト(マグマオーシャン)を配置し，物質境界に適切な摂動を加え，その様子を観察した．

結果と今後の研究: 水平方向に1波長分の不安定なモードが成長するような摂動を加えた場合の結果は添付の図のようになった．図のカラーバーは密度を表している．重い液体金属が液体シリケイトと混和することなく沈降する様子が分かる．
　惑星コア形成問題をグローバルに解くための流体計算の第一歩として，DISPH法の改良を行った．この手法を用いたシミュレーション例として，物性の似ている液体間の二次元レイリーテーラー不安定の問題を解いた．今後は，固体シリケイトを含めた三相二次元問題を考え，その後三相三次元問題に拡張してゆきたい．さらには元素分配も同時に扱えるような粒子法の開発も進めていきたいと考えている．

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

大きさが余緯度θに依存する東西磁場が印加された回転球面上の 2 次元理想磁気流体 (MHD) の線形波動を調べた. 背景磁場が B0Φ = B0 sinθで表される場合 (ここで, B0 は定数, Φ は方位角) は, 西に伝播する速い磁気ロスビー波と東に伝播する遅い磁気ロスビー波の 2 種類が存在することが分かっている. この背景磁場分布以外の場合では, 固有モードの東西位相速度が局所的なアルフべン波速度 (を sinθで割ったもの) と一致するようなところに確定特異点をもつ線形波動の微分方程式を解かなければならない. 臨界緯度の位置は考える固有モードの東西位相速度に依存するため, このことは, 球面上という閉じた領域であるにもかかわらず, アルフべン波の共鳴によって連続モードが生じるということを意味している. 類似の状況には, 非粘性平行シアー流の線形問題があり, これは位相速度と局所的な平均流速が一致するところで臨界層を生じうる (例えば, Case, 1960).

我々は背景磁場が B0Φ = B0 sinθcosθ の場合について数値的に固有値問題を解き, 連続モードが確かに存在することを確かめた. 連続モードの固有周波数は分散関係のグラフ上を面的に広がってしまうため, 離散モードのブランチが連続スペクトルに埋もれて見つかりにくくなっている可能性がある. それゆえ, 我々は各固有モードのエネルギー分配を計算することによって, 連続モードに埋もれた離散モードを拾い出すことを試みた. 注目すべきことは, 今回考えた背景磁場分布の場合には, 遅い磁気ロスビー波の離散的なブランチが見つからなかったことである. このことから理想磁気流体の場合には, 背景磁場分布の選択が, 遅い磁気ロスビー波の出現に影響を及ぼしてしまうことがわかった.

数値計算により, 連続固有モードの構造が求められ, それらが臨界緯度付近でフロベニウスの方法による 2 つの線形独立な解の重ね合わせになっていて, そこでの理論的な接続条件と整合的であることが示された. 印加した磁場の強度が小さいとき, 連続モードの固有関数は, 例外はあるものの, 西進の場合は極側で, 東進の場合は赤道側でエバネッセントになる傾向がある. この特徴は, ゆっくりと空間変化する磁場を伴う回転流体中の高波数の磁気流体波が, 臨界層へ近づいていくが, そこを超えられないという WKBJ 近似の帰結 (Acheson, 1972; Eltayeb & McKenzie, 1977) と整合的である. Acheson (1972) は, ある状況下で磁気流体波は臨界層を横切ることができるという「バルブ」効果を提案したが, 我々が考える問題では, 自転角速度の水平成分が 0 であるので, その効果が起こる条件の範囲外である.

Event date： 2021.5 - 2022.6

Language：Japanese  

Venue：千葉県千葉市幕張メッセ・オンラインハイブリッド   Country：Japan  

Two-dimensional ideal magnetohydrodynamic (MHD) linear waves on a rotating sphere are focused on as a model of a stably stratified layer at the top of the Earth's core. This thin stable layer can accommodate MHD waves which may induce various geomagnetic and geodetic variations (e.g. Gillet et al., 2021[1]; Triana et al., 2021[2]). Under the Malkus background field B0Φ = B0 sinθ, where B0 is a constant, Φ is the longitude and θ denotes the colatitude, linear waves in a thin layer are categorized into two types of branches, which correspond to westward-propagating fast magnetic Rossby waves and eastward-propagating slow counterparts, and on which both modes gradually become Alfvén waves as this field strengthens (Zaqarashvili et al., 2007[3]; Márquez-Artavia et al., 2017[4]). Slow magnetic Rossby waves are especially put weight on as a cause of decadal and subdecadal geomagnetic fluctuations (e.g. Chulliat et al., 2015[5]; Chi-Durán et al., 2021[6]). On the other hand, non-Malkus fields such as plausible toroidal fields within the Earth's core make our linear problem complicated due to the advent of regular singular points in its equation. At these singular latitudes for a given wave, the zonal phase velocity of the wave is equal to the local Alfvén speed at the latitude. In the present presentation, we demonstrate that a non-Malkus field B0Φ = B0 sinθcosθ yields a continuous spectrum and an infinite number of singular eigenmodes instead of slow magnetic Rossby discrete modes, which are worthy of attention in studying Earth's magnetism, and Alfvén ones.

Slowly varying wavetrains in inhomogeneous fields are also investigated to compare with our numerical calculation seeking eigenmodes. This implies that a wave packet of the continuous modes propagates toward the critical latitude corresponding to the wave with its pseudomomentum conserved and is ultimately absorbed there. In addition, we found that the behavior that westward- (eastward-) propagating packets approach the latitudes from the equatorial (polar) side is consistent with the tendency which the profiles of their eigenfunctions have. Further thorough discussions of the continuous spectra possibly improve the theory of wave-mean field interaction and one's understanding of the dynamics in the layer.

The geophysically traditional approximation in which one ignores the inertia term is useful to discuss slow MHD waves including slow magnetic Rossby waves (e.g. Buffett and Matsui, 2019[7]). This approximation can also conveniently rule out the continuous modes, which lead to difficulties with our problem. However, this can have a severe influence on the existence of the critical latitudes, hence eigenmodes significantly different from the original. We therefore urge that one should not carelessly drop the inertial effect in the system in which main fields possess spatial dependence.

[ Reference ]
[1] Gillet, N., Gerick, F., Angappan, R., Jault, D. (2021) Surv. Geophys., doi: 10.1007/s10712-021-09664-2
[2] Triana, S.A., Dumberry, M., Cébron, D., Vidal, J., Trinh, A., Gerick, F., Rekier, J. (2021) Surv. Geophys., doi: 10.1007/s10712-021-09668-y
[3] Zaqarashvili, T.V., Oliver, R., Ballester, J.L., Shergelashvili, B.M. (2007) Astron. Astrophys., 470, 815–820, doi: 10.1051/0004-6361:20077382
[4] Márquez-Artavia, X., Jones, C.A., Tobias, S.M. (2017) Geophys. Astrophys. Fluid Dyn., 111, 282–322, doi: 10.1080/03091929.2017.1301937
[5] Chulliat, A., Alken, P., Maus, S. (2015) Geophys. Res. Lett., 42, 3321-3329, doi: 10.1002/2015GL064067
[6] Chi-Durán, R., Avery, M.S., Buffett, B.A. (2021) Geophys. Res. Lett., 48, e2021GL094692, doi: 10.1029/2021GL094692
[7] Buffett, B., Matsui, H. (2019) Geophys. J. Int., 218, 1210–1225, doi: 10.1093/gji/ggz233

Event date： 2020.7

Language：Japanese  

Venue：オンライン   Country：Japan  

Magnetohydrodynamic (MHD) shallow water linear waves are examined on a rotating sphere with a background toroidal magnetic field expressed as B0Φ=B0sinθ, where B0 is constant, θ is the colatitude and Φ is the azimuth. The MHD shallow water equations are often used in studying the dynamics of the solar tachocline (e.g. Gilman & Dikpati, 2002[1]; Márquez-Artavia et al., 2017[2]) and sometimes the outermost Earth's core (Márquez-Artavia et al., 2017[2]; Nakashima, Ph.D. thesis, 2020[3]) and exoplanetary atmosphere (e.g. Heng & Workman, 2014[4]). In this poster, we especially focus on the propagation mechanisms and the force balances of polar trapped waves and unstable modes (Márquez-Artavia et al., 2017[2]; Nakashima, Ph.D. thesis, 2020[3]).

Comprehensive searches for eigenmodes yield two polar trapped modes when the main magnetic field is weak (the Lehnert number α=VA/2ΩR2<0.5, where VA is the Alfvén wave velocity, Ω is the rotation rate and R is the sphere radius). One is the slow magnetic Rossby waves, which propagate eastward for zonal wave number m≧2 (Márquez-Artavia et al., 2017[2]). As the Lamb's parameter ε=4Ω2R2/gh→0 (where g is the gravity acceleration and h is the equivalent depth), these branches asymptotically approach the eigenvalues of two-dimensional slow magnetic Rossby waves. Another is newly discovered westward polar trapped modes (Nakashima, Ph.D. thesis, 2020[3]).

In the case when α>0.5 (the background field is strong), these novel westward modes merge with the westward-propagating fast magnetic Rossby waves. In addition, only when m=1, polar trapped unstable modes appear due to the interaction between these fast magnetic Rossby waves and westward-propagating slow magnetic Rossby waves. These growth modes are believed to be the polar kink (Tayler) instability (Márquez-Artavia et al., 2017[2]).

In order to easily understand the propagation mechanisms and the force balances of polar trapped modes, we investigate a cylindrical model around a pole with an artificial boundary condition. This model provides the approximate dispersion relations and eigenfunctions of polar trapped modes, and indicates that stable polar trapped modes are governed by magnetostrophic balance and that the metric magnetic tension force causes the difference between the slow magnetic Rossby waves and the novel westward modes. For m=1 and α>0.5, the balance between Coriolis and Lorentz forces is disrupted and the part of magnetic tension with which Coriolis force can not compete induces kink instability.

[ Reference ]
[1] Gilman, P. A., Dikpati, M. (2002) Astrophys. J., 576, 1031. doi: 10.1086/341799
[2] Márquez-Artavia, X., Jones, C. A., Tobias, S. M. (2017) Geophys. Astrophys. Fluid Dyn., 111, 282. doi: 10.1080/03091929.2017.1301937
[3] Nakashima, R. (2020) Ph.D. thesis, Kyushu University. http://dyna.geo.kyushu-u.ac.jp/HomePage/nakashima/pdf/doctoral_thesis.pdf
[4] Heng, K., Workman, J. (2014) Astrophys. J. Sup., 213, 27. doi: 10.1088/0067-0049/213/2/27

Event date： 2020.7

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Magnetohydrodynamic (MHD) shallow water linear waves are investigated over a rotating sphere with an imposed equatorially antisymmetric toroidal magnetic field: B0Φ=B0sinθcosθ, where B0 is a constant, θ is the colatitude and Φ is the azimuth. This system can imitatively represent the dynamics of a liquid metal within a stably stratified layer at the top of the Earth's core, which was detected through seismological surveys (e.g. Helffrich & Kaneshima, 2010[1]) and also has been deduced from geophysical and geochemical knowledge (e.g. Buffett & Seagle, 2010[2]; Pozzo et al., 2012[3]; Gubbins & Davies, 2013[4]; Brodholt & Badro, 2017[5]). Because slowly propagating waves in the liquid core can result in geomagnetic secular variations, comparison between exhaustive studies of MHD waves in a rotating stratified fluid and observations of geomagnetic fluctuations should provide constraints on the obscure stratified layer in the outermost core (e.g. Braginsky, 1993[6]; Buffett, 2014[7]).

The adopted configuration of the background field complicates solving the eigenvalue problem of linear waves due to the emergence of an Alfvén continuum and critical latitudes unless dissipation effects are taken into account. These result from non-dissipative Alfvén resonance, which occurs only when B0Φ/sinθ depends on θ, that is, regular singular points appear in the differential equation of linear problems. The solutions of the continuum are required to express the transient evolution of an arbitrary initial disturbance (e.g. Case, 1960[8]; Goedbloed & Poedts, 2004[9]). We can confirm numerically and analytically that introducing magnetic diffusion eliminates these Alfvén continuous modes and their singular structures around critical latitudes (Nakashima, Ph.D. thesis, 2020[10]).

For the Earth's core-like parameter (B0≃0.5—5mT and magnetic diffusivity η≃1m2/s), westward polar trapped modes are obtained as eigenmodes, which have a period of around from several to 1000 years. We may be able to observe these modes as geomagnetic secular variations in high latitude regions, if the strength of stratification in the stratified layer is close to the estimate of Buffett (2014)[7]. The analyses of recent geomagnetic models and paleomagnetic data in terms of such waves could confirm the robustness of previous estimates of the properties of the layer.

[ Reference ]
[1] Helffrich, G., Kaneshima, S. (2010) Nature, 468, 807. doi: 10.1038/nature09636
[2] Buffett, B. A., Seagle, C. T. (2010) J. Geophys. Res., 115, B04407. doi: 10.1029/2009JB006751
[3] Pozzo, M., Davies, C., Gubbins, D., Alfè, D. (2012) Nature, 485, 355. doi: 10.1038/nature11031
[4] Gubbins, D., Davies, C. J. (2013) Phys. Earth Planet. Inter., 215, 21. doi: 10.1016/j.pepi.2012.11.001
[5] Brodholt, J., Badro, J. (2017) Geophys. Res. Lett., 44, 8303. doi: 10.1002/2017GL074261
[6] Braginsky, S. I. (1993) J. Geomag. Geoelectr., 45, 1517. doi: 10.5636/jgg.45.1517
[7] Buffett, B. (2014) Nature, 507, 484. doi: 10.1038/nature13122
[8] Case, K. M. (1960) Phys. Fluids, 3, 143. doi: 10.1063/1.1706010
[9] Goedbloed, J. P., Poedts, S. (2004) Principles of magnetohydrodynamics: with applications to laboratory and astrophysical plasmas, Cambridge Univ. Press, Cambridge.
[10] Nakashima, R. (2020) Ph.D. thesis, Kyushu University. http://dyna.geo.kyushu-u.ac.jp/HomePage/nakashima/pdf/doctoral_thesis.pdf

Event date： 2019.10

Language：Japanese  

Venue：熊本市国際交流会館（熊本市）   Country：Japan  

Shallow water MHD waves trapped in the polar regions on a rotating sphere with an imposed azimuthal magnetic field

Event date： 2019.5

Language：Japanese  

Venue：幕張メッセ（千葉市）   Country：Japan  

Magnetohydrodynamic (MHD) waves in a thin layer on a rotating sphere with an imposed toroidal magnetic field are investigated. The system is often considered as a model of the stably stratified outermost Earth's outer core or the tachocline of the Sun. The stratification of the outermost core is suggested on the basis of seismological evidence (e.g. Helffrich and Kaneshima, 2010; Kaneshima, 2018) and interpretations of the geomagnetic variations with MHD waves (e.g. Braginsky, 1993; Buffett, 2014; Chulliat et al., 2015). In order to provide constraints on the obscure stratified layer by comparing with wavy variations in the geomagnetic field, we studied the linear waves of the two-dimensional MHD and the MHD shallow water system over a rotating sphere.
We adopt an azimuthal equatorially antisymmetric field (BΦ(θ) = B0 sinθcosθ, where θ is colatitude, Φ is azimuth) as a background magnetic field. On the other hand, an equatorially symmetric field (BΦ(θ) = B0sinθ) was assumed in Márquez-Artavia et al.(2017), whose results we replicated and reported in JpGU 2018.
Compared with previous results, the dispersion diagrams obtained with the toroidal equatorially antisymmetric field show that some fast magnetic Rossby branches remain, while slow magnetic Rossby waves disappear. Besides, a continuous spectrum is found in the range where an azimuthal phase velocity is coincident with a local Alfvén velocity divided by sinθ. Similar continuous spectra are also seen in
various physical situations, including inviscid shear flow (e.g. Case, 1960; Balmforth and Morrison, 1995; Iga, 2013) and plasma oscillations (e.g. Van Kampen, 1955; Case, 1959; Barston, 1964; Sedláček, 1971). The continuous spectra are accompanied by a singular eigenfunction, which is physically meaningful only when they are integrated over the continuous spectra. Its integrated solutions generally decay with time, which is referred to as phase mixing. Unlike exponentially damped discrete modes, this decaying is proportional to negative powers of time.
In the case of the shallow water system with the antisymmetric field, discrete eigenvalues buried in the continuous spectrum is found, which include unstable modes. For the Earth-like parameters, polar trapped modes with decadal period and equatorial trapped Rossby waves with a few years period are found when the stratification is weak.

Event date： 2018.5

Language：English  

Venue：幕張メッセ（千葉市）   Country：Japan  

We investigated waves in a stably stratified thin layer in a rotating sphere with an imposed magnetic field. This represents the stably stratified outermost Earth's core or the tachocline of the Sun. Recently, many geophysicists focus on the stratification of the outermost outer core evidenced through seismological studies (e.g. Helffrich and Kaneshima, 2010) and an interpretation of the 60-year geomagnetic secular
variations with Magnetic-Archimedes-Coriolis (MAC) waves (Buffett, 2014).
Márquez-Artavia et al.(2017) studied the effect of a toroidal magnetic field on shallow water waves over a rotating sphere as the model of this stratified layer. On the other hand, MAC waves are strongly affected by a radial field (e.g. Knezek and Buffett, 2018). We added a non-zero radial magnetic perturbation and magnetic diffusion to Márquez-Artavia et al.(2017)'s equations. Unlike their paper's formulation, we applied velocity potential and stream function for both fluid motion and magnetic perturbation, which is similar to the first method of Longuet-Higgins(1968). In the non-diffusive case, the dispersion relation obtained with the azimuthal equatorially symmetric field (Bφ(θ) ∝sinθ, where θis colatitude) is almost the same as Márquez-Artavia et al.(2017)'s result, which includes magneto-inertia gravity (MIG) waves, fast magnetic Rossby waves, slow MC Rossby waves and an unexpected instability. In particular, we replicate the transition of the propagation direcition of zonal wavenumber m=1 slow MC Rossby waves from eastward to westward with increasing Lamb parameter (ε=4Ω^2 a^2/gh, where Ω, a, g and h is the rotation rate, the sphere radius, the acceleration of gravity and an equivalent depth, respectively) and Lehnert number (α=v_A/2Ωa, where v_A is Alfvén wave speed). As a consequence, fast magnetic Rossby waves and slow MC Rossby waves interact, and the non-diffusive instability occur.
Next, we are examining the case with an equatorially antisymmetric background field, which is more realistic in the Earth's core. In this case, if the magnetic diffusion is ignored, the continuous spectrums appear owing to Alfvén waves resonance (similar to the continuous spectrums in inviscid shear flow, e.g. Balmforth and Morrison, 1995). To solve this difficulty, our numerical model includes the magnetic diffusion term.

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡市、ホテルポートヒルズ福岡   Country：Japan  

A possible stably stratified layer at the top of the outer core --the compositional evolution of the outer core

Event date： 2017.5

Language：Japanese  

Venue：幕張メッセ（千葉市）   Country：Japan  

Equatorial waves modified by the presence of a toroidal magnetic field within the stably stratified layer at the top of the Earth’s outer core

Event date： 2016.5

Language：Japanese  

Venue：幕張メッセ（千葉市）   Country：Japan  

Empirical mode decomposition of the decadal variation of the Gauss coefficients

Event date： 2015.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ（千葉市）   Country：Japan  

The boundary mode of axially symmetric MAC waves can exist in the stratified layer at　the top of the Earth’s outer core

Event date： 2015.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ（千葉市）   Country：Japan  

Spontaneous rotation of a block ice melting on metal surface

Event date： 2014.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京大学大気海洋研究所講堂（柏市）   Country：Japan  

Spontaneous rotation of a melting ice block

Event date： 2014.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡国際会議場（福岡市）   Country：Japan  

Spontaneous rotation of a melting ice block

Event date： 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学川内北キャンパス講義棟（仙台市）   Country：Japan  

Spontaneous rotation of a block of ice on a flat surface of a warm metal column

Event date： 2013.10

Language：English  

Venue：新潟大学（新潟市）   Country：Japan  

Linear stability analysis of two-layer thermal convection and the generation of surface flow of gas giants

Event date： 2013.10

Language：English   Presentation type：Oral presentation (general)  

Venue：新潟大学（新潟市）   Country：Japan  

Introduction to the geodynamo theory and the alpha effect

Event date： 2013.5

Language：Japanese  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

A model of modern science and its working: Dual Feedback-Loop Operator

Event date： 2013.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

The history of the study on the Earth’s inner core with the aid of a scientometric method

Event date： 2013.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

How to write the history of geoscience -right and wrong of Whig interpretation of history-

Event date： 2013.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

The evolution of behavioral modernity and the evolution of science

Event date： 2013.4 - 2013.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：パシフィコ横浜（横浜市）   Country：Japan  

Spontaneous rotation of a block of ice on a flat surface of a warm metal column

Event date： 2012.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京外国語大学（東京都府中市）   Country：Japan  

Event date： 2012.8

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福島県・くつろぎ宿千代滝   Country：Japan  

Event date： 2012.5

Venue：幕張メッセ国際会議場（千葉県千葉市）   Country：Japan  

Models and Simulations in Geosciences

Event date： 2012.5

Presentation type：Oral presentation (general)  

Venue：幕張メッセ国際会議場（千葉県千葉市）   Country：Japan  

Historical reconstruction in science

Event date： 2012.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

From philosophy of science to science of science - A casestudy on earth science

Event date： 2012.5

Language：Japanese  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

Model, where earth science and the philosophy of science meets

Event date： 2012.5

Language：Japanese  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

How to launch the Science of Science

Event date： 2012.5

Language：Japanese  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

A natural view of the World in philosophy of science provided by interpretation of the Earth’s evolution history

Event date： 2012.5

Language：Japanese  

Venue：幕張メッセ国際会議場（千葉市）   Country：Japan  

Where and how did science come from? A cognitive approach.

Event date： 2011.11

Presentation type：Symposium, workshop panel (public)  

Venue：日本大学文理学部（東京都世田谷区）   Country：Japan  

Methodology of science studies and the science of future

Event date： 2011.11

Presentation type：Symposium, workshop panel (public)  

Venue：日本大学文理学部（東京都世田谷区）   Country：Japan  

The reason we began to study the philosophy of science -- as an extension of the project "Decoding the Earth's Evolution"

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：阿蘇白雲山荘（熊本県阿蘇市）   Country：Japan  

The alpha effect in the dynamo theory

Event date： 2010.5

Presentation type：Oral presentation (general)  

Venue：幕張メッセ　国際会議場   Country：Japan  

Evaluating Akiho Miyashiro's philosophy of science

Event date： 2010.4

Presentation type：Symposium, workshop panel (public)  

Venue：北海道大学　人文・社会科学総合教育研究棟   Country：Japan  

Usage of the term "model" in science

Event date： 1998.7

Language：English  

Venue：Seattle, WA, USA   Country：Other  

A method to examine the shifts in individual surface features in multi-temporal SAR images has been proposed. First, line-like and boundary-like features were extracted from SAR imagery using the pixel swapping method. The extracted feature images were then tied to observe an overall shift in individual features. We applied this method to two JERS-1 SAR images of the same path-row observed on different dates. We observed that the shift in flat areas was simple, but that in mountainous regions, there was a clear difference in the direction of the shift in ridges and valleys caused by the slightly different orbital characteristics of the satellite between the two images. In addition, care in choosing appropriate tie points was found to be important. The method used in this investigation is expected to be useful in planning an appropriate strategy for the coregistration of images, such as in SAR images used for change detection in environmental monitoring, and InSAR.

Type：Competition, symposium, etc. 

Number of participants：30

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Peer review 

Number of peer-reviewed articles in foreign language journals：1

Type：Scientific advice/Review 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Academic society, research group, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Scientific advice/Review 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Audience：Infants,　Schoolchildren,　Junior students,　High school students

Type：Seminar, workshop

Audience：General,　Scientific,　Company,　Civic organization,　Governmental agency

Type：Lecture

打ち上げ自体は悪天候のため延期になったので、講演会、ビデオ上映、ジバニャン撮影会、学生による関連研究展示などが行われた。

Audience：Infants,　Schoolchildren,　Junior students,　High school students

Type：Other

Audience：Infants,　Schoolchildren,　Junior students,　High school students

Type：Other