巻号一覧
47 巻 (2001)
- 4 号 p. 755-
- 3 号 p. 701-
- 2 号 p. 629-
- 1 号 p. 1-
47 巻, 2 号
選択された号の論文の12件中1～12を表示しています
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大江 昌嗣, 松本 晃治2001 年 47 巻 2 号 p. 629-636
発行日: 2001/06/25
公開日: 2010/09/07
ジャーナル フリーLumar tidal effects to orbits of the lunar satellite in the SELENE mission are investigated. We present numerical simulation results for the tidal perturbation of the orbits of spacecraft. The obtained analytic solutions suggest that the orbiter and the relay satellite shift, respectively, by 40 m to 15 m at the maximum from nominal orbits owing to the tidal force with monthly periods. Doppler and VLBI observations are planned for determination of precise orbits. In this mission it is considerably important how to correct and/or how to analize the tidal effects of the orbits. The present estimate serves to plan the observations . A more realistic model of the lunar interior, however, would be required, if we could determine the admittance factor and Q value of the tide on the Moon through the forthcoming observations.抄録全体を表示PDF形式でダウンロード (791K) -
鈴山 智也, 川口 則幸, 栗原 則幸, 宮崎 智行2001 年 47 巻 2 号 p. 637-648
発行日: 2001/06/25
公開日: 2011/03/01
ジャーナル フリーA highly precise VLBI (Very Long Baseline Interferometer) observation system, which is composed simply and at low cost, is proposed. In the higher-order sampling system, a received IF signal of 0.1-2.0 GHz is separated into four bands by band-pass filters with a 32 MHz band width in the zero-redundant array, and then sampled by a signal analog-to-digital converter with 1-bit quantization. The output digital data stream is at 256 Mbps . Test observations were done using the 34 m antenna at Kashima, Ibaraki Prefecture and the 10 m antenna at Mizusawa, Iwate Prefecture to find the fringes toward eight cosmic radio sources at each IF channel. The cross spectra of the synthesized IF channels were clearly separated from each other, as a result of using the proper fringe frequencies, which eliminate unwanted multiplexed signals.抄録全体を表示PDF形式でダウンロード (2134K) -
－瀬戸内海高重力異常帯－河野 芳輝, 西山 吉介, 井口 博夫2001 年 47 巻 2 号 p. 649-658
発行日: 2001/06/25
公開日: 2011/07/05
ジャーナル フリーThe Seto Inland Sea (Seto-naikai) was one of the largest areas of poor distribution of gravity stations in the Japanese Islands. In June of 1991, we visited 65 islands in the central to eastern part of this area for gravity measurements by employing a small boat (6 .5 ton). More than 300 gravity measurements were carried out in this area. The measured data revealed an existence of a high Bouguer anomaly zone along the central part of the Seto Inland Sea. The length and width of the zone are about 180 km and 30 km, respectively. Bouguer anomaly is higher about 20 mgal than the surrounding areas. We named the zone as the “High Gravity Anomaly Belt in the Seto Inland Sea”. It is difficult to interpret this high anomaly belt as a consequence only due to density differences of surface geology, because the studied area is widely covered by granitic rocks. We suggested a possibility that Sanbagawa metamorphic rocks, or similar high-density rocks, presumably exist at shallow depth beneath this area.抄録全体を表示PDF形式でダウンロード (1333K) -
藤原 了, 橋本 学, 竹本 修三2001 年 47 巻 2 号 p. 659-678
発行日: 2001/06/25
公開日: 2011/03/01
ジャーナル フリー三次元有限要素法を用いて琉球弧をモデル化し,粘性流体媒質中の定常流の仮定下で流れ及び応力場を計算した.背弧直下に想定される低密度媒質及び一般的なプレート運動の原動力の背弧拡大に対する効果,地殻粘性率の影響について考察した.解析の結果,スラブ引っ張り力やリッジプッシュ等のみを考慮したモデルでは背弧地域に圧縮場を形成した.一方,背弧直下での低密度媒質に働く浮力を考慮した場合,背弧における拡大を示唆する張力場が得られた.背弧直下の低密度媒質は地殻付近の深さまで到達している可能性が高く背弧拡大の主原動力と考えられる.さらにマントルの粘性率と背弧領域の地殻粘性率との差が小さい時,すなわち相対的に軟らかいプレートを仮定した時に拡大が生じた.抄録全体を表示PDF形式でダウンロード (3974K) -
福田 洋一, Lorant Foldvary2001 年 47 巻 2 号 p. 679-685
発行日: 2001/06/25
公開日: 2011/03/01
ジャーナル フリーWe propose a practical method and discuss some problems related to corrections for the gravity effects of fluid envelope of the Earth, i. e., the atmosphere, the ocean and/or land water using coming satellite gravity data . Recent progress of precise gravity measurements using superconducting gravimeters (SG) and/or absolute gravimeters (AG) enables us to study thevery weak signals (less then a few micro gals) of long-term gravity changes due to polar motion effects, post-glacial rebounds, crustal movements, sea level changes, and other various phenomena. Besides these, mass redistribution of the fluid envelope causes global gravity changes mainly in the seasonal frequency band . Since the gravity changes observed by the gravimeters are the integrated sum of all these signals, we need to extract a desired signal or to correct unnecessary signals depending on the purpose of the study. A new satellite gravity mission GRACE will be expected to provide a time series of global gravity fields coefficients with an interval of about one month. Hence, we will be able to use the coefficients for the correction of the gravity changes due to the global mass redistribution. Conversely, we may use the surface gravity measurements as a validation tool ofthe satellite data. The principle of the correction is rather simple; 1) calculate equivalent surface mass changes from the observed gravity coefficients, and 2) calculate the gravity changes at a station with Green's functions for loading effects and attraction . However, there are some practical problems related to the selection of the green functions, high frequency aliasing, local effects, zero definitions, and so on . We will discuss these problems by simulation studies using gravity coefficients estimated from reanalysis and model data sets of the fluid envelope.抄録全体を表示PDF形式でダウンロード (1004K) -
加藤 照之2001 年 47 巻 2 号 p. 687-692
発行日: 2001/06/25
公開日: 2010/09/07
ジャーナル フリーPDF形式でダウンロード (781K) -
2001 年 47 巻 2 号 p. 699
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (130K) -
2001 年 47 巻 2 号 p. 700a
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (103K) -
2001 年 47 巻 2 号 p. 700b
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (103K) -
2001 年 47 巻 2 号 p. 700c
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (103K) -
2001 年 47 巻 2 号 p. 700d
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (103K) -
2001 年 47 巻 2 号 p. 700e
発行日: 2001年
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (103K)
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