巻号一覧
15 巻 (1969 - 1970)
- 4 号 p. 103-
- 2-3 号 p. 41-
- 1 号 p. 2-
15 巻, 4 号
選択された号の論文の10件中1～10を表示しています
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藤田 尚美, 井内 登1970 年 15 巻 4 号 p. 103-111
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリーSome methods deriving the anomalies of geomagnetic components from observed values of the anomaly of total force are proposed by one (N.F.) of the writers [1]. Between the anomaly of total force and the geomagnetic potential at grid points in a plane the following equation holds.
2πs F0/Z0 ΔF(i, j)=∞Σμ=-∞∞Σν=-∞Φ(μ, ν)W(i+μ, j+ν),
where s is the spacing of grid points and Φ(μ, υ) is the weighting function given by (19). The anomalies of geomagnetic components are obtained from (7), (8) and (9). The following assumptions are involved in this method.1) W-surface considered as the group of small planes.2) W=O outside the area of grid points.3) The normal values Xo, Yo, Zo and Fo are approximately known and the approximation shown in (7) is adopted. In the actual procedure, the density of grid points is determined considering the pattern of ΔF observed. The surveying area is divided into blocks with suitable size and these blocks are overlapped to some extent. From the results (Figs 2.-4) of computation using the model combined two dipoles, it is clarified that the anomalies of geomagnetic components can be computed in almost the same accuracy of dF observed. In the southern part of Kanto district where the total force is only measured in the aeromagnetic survey (Fig. 5), the anomalies of geomagnetic components are obtained as shown in Fig. 6.抄録全体を表示PDF形式でダウンロード (691K) -
水野 浩雄1970 年 15 巻 4 号 p. 112-120
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリーThe problem of dynamo action of tidal stream or ocean current in the earth's magnetic field has a long history of research. I investigated the effect of magnetic field induced by this action on geomagnetic observations. This problem seems very important to assure the accuracy of geomagnetic observations, because Japan islands are surrounded by sea and high speed ocean currents such as Kuroshio and Oyashio flows. The vertical component observed at Shimosato shows a remarkable seasonal variation. The relation between this phenomena and Kuroshio has been expected to be its origin. I calculated the induced magnetic field for a simple model of ocean current which flows straight with semi-elliptic cross section. This field is restricted in water and amounts to about 37 r/knot in magnitude. However, possible leakage of flux of this field which approaches near peninsura or encounters island is so small that ordinary magnetic measurement on land is not practically influenced. Seasonal variation at Shimosato can hardly be explained by this line of thought. The magnetometer in water may be disturbed by this induced field to the order of ten gammas according to circumstances. We may obtain information about the path of ocean current to a certain degree, with a suitable distribution of magnetometers in water.抄録全体を表示PDF形式でダウンロード (877K) -
田島 稔, 佐藤 裕, 須田 教明1970 年 15 巻 4 号 p. 121-129
発行日: 1970/06/25
公開日: 2011/07/05
ジャーナル フリーAn experimental temperature observation of lower atmospheric layer was made for the purpose of improving the accuracy of electro-optical distance measurement near Mt. Kano, Boso peninsula in summer 1969. The instrument consists of a thermister sensing head suspended by a Kytoon of 15 m3 in volume, the altitude of which is 300 m in maximum and transistorized transmitter. The temperature signal from the sonde is received at the ground and recorded continuously with the accuracy of 0.2°C. The temperature difference between 200 m altitude and the ground shows clear local time dependence of which amplitude is about 3-4°C. The calculated temperature values at the middle point of the sight line by using the meteorological data at the two end stations has a discrepancy of about 2-3°C against the values obtained directly by means of Kytoon, which corresponds to the error of 2-3x 10-6 in distance measurement. Using the observed temperature gradient, the refraction coefficient was also calculated, the value being almost same as the result obtained by Hopcke.抄録全体を表示PDF形式でダウンロード (4333K) -
石井 晴雄1970 年 15 巻 4 号 p. 130-141
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリーIn 1958, Prof. I. Tsubokawa proposed a gravity meter with three strings intersecting at right angles to one another as shown in Fig. 1. The principle of measurement is as follows [1]. Let the components of gravity along three strings be g1, g2 and g3, and the frequencies of the strings 1, 2 and 3 be f1, f2 and f3 respectively, then
g2=g12+g22+g32
g1=a1f12, g2=a2f22, g3=a3f32}(1)
where a1, a2 and a3 are the coefficients which depend on the dimentions, linear density and elasticity of the strings and the weight. Let the respective angles between the strings be α12, α23 and α31, where α12=90°-ε12, α23=90°-ε23 and α31=90°-ε31.
g=√a12f14+a22f24+a32f34+2a1a2f12f22sinε12+2a2a3f22f32sinε23+2a3a1f32f12sinε31 (2)
We assume construction accuracies of gravity meter as follows;
1) ε12, ε23, ε31<1×10-3
2) a1, a2 and a3 are equal in the accuracy of 1×10-3
By integration Eq. (2) from time O to T, the value of the gravity difference between the starting and observation stations Δg can be expressed as
The suffix 0 corresponds to the starting station and s the observation station. In this equation, gh is the horizontal acceleration due to the ship's movement and the last term is the Eötvös correction, in which V is the speed of the ship in knot, ψlatitude and A the azimuth of the course. Gravity survey was carried out on the sea around Japan during the period from April to June in 1969 on the board "Hakuhop-maru" belonging to the Ocean Research Institute, the University of Tokyo. The ships' tracks are shown in Fig. 4 with profile No. of gravity anomaly. The plofiles of free air and Bouguer anomalies are shown in P. 1-17 with bottom topography.抄録全体を表示PDF形式でダウンロード (4819K) -
(日本西南部太平洋岸の場合)林 哲郎, 一色 朗, 藤田 尚美1970 年 15 巻 4 号 p. 142-149
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリーIn this paper, the writers discussed the effects of the oceanographic conditions to the yearly mean sea level along the Pacific coast in the south-western part of Japan. As the elements of the oceanographic conditions, the mean water temperature from sea surface to 200 meters depth and the situation of the axis of Kuroshio-current were considered. In order to correct these effects to the yearly mean sea level, the relations between the sea level and these oceanographic conditions were investigated. The main conclusions resulted from above investigations are as follows. (1) The greater part of the fluctuation of sea level is due to the effect of the variation of sea water temperature. Particularly this effect is conspicuous at Aburatsubo and Mera. (2) The variation of the situation of the current-axis is also an element that fluctuates largely the sea level. The fluctuations of sea levels at Nagoya, Shimizu-minato, Aburatsubo, and Mera seem to be affected by the latitude of the most southern part of the current-axis of Kuroshio on the offing Enshu-nada. On the other hand, the fluctuations of sea level at Kushimoto and Kochi seem to relate with the longitude of the current-axis. These facts may be caused by the fluctuations of water temperature in the sea near the tidal station and of the current along the coast which are due to the variation of meandering Kuroshio-current. (3) The fluctuations of the yearly mean sea levels at the tidal stations may contain the effects of the sea water temperature and of the situation of the current-axis. At the tidal stations, Mera, Aburatsubo, Shimizu-minato, Nagoya and Kushimoto, these effects amount to about 70 percents of the fluctuations of yearly mean sea levels, and the standard deviations of the yearly mean sea levels from the linear variations are reduced about 10 millimeters.抄録全体を表示PDF形式でダウンロード (822K) -
田島 稔, 瀬戸 孝夫1970 年 15 巻 4 号 p. 150-157
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリー国土地理院所属の鹿野山測地観測所における地磁気観測業務の一部が房総西線の直流雹化により支障をきたしたため,岩手県水沢市東方に新たな観測所(水沢測地観測所)を設置することになつた.この際,ごく小数の職員で地磁気連続観測を維持できるように,観測器械の改良を下記の如く行つた. (1)従来の地磁気変化の印画紙記録方式を三成分とも電流帰還型の直視方式にし,記録紙取り換えの手間を省いた. この原理は,H,.D,Z三成分変化計の感度試験用ヘルムホルッコイル枠に,もう一組の変化磁場補償用巻線を加えたものである.光源から出た光はmoving magnetの鏡で反射され受光部に入る.受光部はシリンドリカルレンズを2個はり合せたもので,光路が2つに分けられ,それぞれがCdS感光体に入射する.磁場変化によるスポットの変位は,CdSブリッジに誤差電圧を生じ,増幅されてサーボモーターを駆動し,可変抵抗を調整することにより変化磁場を打ち消す電流を得る.磁場変化に対応した電流は標準抵抗を通し,電圧出力としてERB型の多点記録機に記録される. (2)プロトン磁力計によるF,Hの測定を1分ごとに行い,アナログ記録と同時に,ディジタル記録もとることにした.特に観測所業務で従来多くの時間を要した三成分の毎時平均値を自動的に求めるようにするために,プリンターに,1分ごとの値とともに,毎時間の60回分の積算値も印字させるようにした.しかし三成分のうち偏角についてはプロトン方式よりもD変化計をセンサーに使用する方が簡単なため,直視型D変化計(Suspension magnet type)の出力をA-D変換し,プロトンからのF,Hとともに同じ方式で印字させるようにした.印字の最少単位はF,Hについては0.1γまで可能であり,Dは0.1である.またこれらの印字と並行しテープ穿孔装置も取付けが可能になつている. (3)偏角についてはF,Hと異なり絶対値を獲得しているわけではないので,絶対観測室にてGSI型磁気儀による地磁気ベクトルの方向観測を定期的に行ない,変化計の出力電圧に,基線値に対応する半固定電圧を加えることにより,その時々に対応した値の表示と印字,積算を行なつている. 以上の改良により,すべての装置の記録状態を事務室に隣接した記録計室で直視できるとともに,時間平均値の読み取りは半自動化され,少数の職員による観測業務の維持が可能となつた.抄録全体を表示PDF形式でダウンロード (3321K) -
角田 忠一1970 年 15 巻 4 号 p. 158-166
発行日: 1970/06/25
公開日: 2011/07/05
ジャーナル フリーPDF形式でダウンロード (1304K) -
笠原 慶一1970 年 15 巻 4 号 p. 167-172
発行日: 1970/06/25
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (620K) -
山口 生知1970 年 15 巻 4 号 p. 173-177
発行日: 1970/06/25
公開日: 2010/09/07
ジャーナル フリー1.Lagos(Lisbon),Portuga1におけるOct.,1908からDec.,1958まで約50年間の平均海水面変化について調べてみた. 2.日本各地,およびU.S.A.のSan Francisco,Los Angelesのときと同様に先ず各月に対する平年値(50年間)を計算した. 3.次いで,この平年値からのmonthly deviations,△ L'を求め,それらの12ヵ月の平均を計算して,年次に対して画いたのが年変化曲線である. 4.この曲線の上に大地震の起つた年次,地震のmagnitude,震源距離を記して見た. 5.上の図を見ると,大地震の5年前の1936年頃から急に下り出して,1940年には極端に下つて1941年から少しずつ上り出し,その年の11月にLisbonの沖約600kmのところにM=8.3という大地震が起きていることを知つた. 6.上の様子は日本の多くの地震の場合,特に新潟地震のとき鼠ケ関の潮位年平均曲線の場合とよく似ている. 7.しかし,日本の場合も,今回のLagosの場合も地震のmagnitudeが7.3以下であり,またそれが陸地に起る場合には余り著しい年平均潮位変化は認められないことを附記しておく.抄録全体を表示PDF形式でダウンロード (461K) -
佐藤 裕1970 年 15 巻 4 号 p. 177-180
発行日: 1970/06/25
公開日: 2010/09/07
ジャーナル フリーPDF形式でダウンロード (291K)
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