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Volume 16 (1970 - 197･･･
- Issue 4 Pages 177-
- Issue 3 Pages 99-
- Issue 1-2 Pages 1-
Volume 16, Issue 3
Displaying 1-10 of 10 articles from this issue
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Kennosuke HOSOYAMA1971 Volume 16 Issue 3 Pages 99-110
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSContinuous observations of the earth tides with Verbaandert-Melchior pendulums at Akagane Observation Station was commenced in 1967. Hourly reading values of the records have been sent every three months to the International Centre of the Earth Tides at the Royal Observatory of Belgium. On the other hand, the data have beenn analyzed successively by means of Lecolazet's method in our observatory.
Tidal factors of four main waves were determined by the analysis, but they were very peculiar values in comparison with that of global values of 0.60.8. As shown in Table II, γ of the diurnal waves were larger than 1.0, on the contrary, that of the semidiurnal waves were too small. After detailed examinations it was considered to be affected mainly by the oceanic tides, because the observation station was located merely 50 kilometers distant from the pacific coast.
Attraction (A) of oceanic waters, the flexure (B) of the earth's crust due to the water and the potential variation (C) due to the earth's flexure were calculated using co-tidal maps under the following assumptions.
For the first approximation, the Boussinesq's formula for solving the deformation of the earth due to surface load was applied. Then, the total oceanic term was expressed as, A+B+C =(1+υ+ε)A. The value of v increases proportional to the depth, and it iss expressed as the hyperbolic function,
υ=C2/γ+C1,
where r denotes angle distance in degree between the observation station and the point mass. C1 and C2 depend on underground structure and distribution of the rigidity.
In this paper, the values of C1, C2 and ε are adopted as 12.6, 3.0 and 0.5 respectively, which were determined by Dr. Nishimura.
Consequently, the total oceanic term was expressed as follows,
A+B+C=(1+12.6/γ+3.0-0.5)·A.
The corrected values of ?A for M2 wave became larger than that of previous values as shown in Table IV. The first approximation shows good result, and further investigations for local indirect effect of oceanic tides are now continued.View full abstractDownload PDF (1132K) -
Yoichiro FUJII1970 Volume 16 Issue 3 Pages 111-126
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSIn 1968, H. Moritz proposed a linear solution of the geodetic boundary value problem instead of M. S. Molodensky's rigorous solution. This solution may be usuful in case of moderate distribution of gravity anomaly and topography, but some danger may be afraid in case of predominant short wave length of gravity anomaly and topography. The author transformed G1 term in M.S. Molodensky's solution into topographic correction term in usual gravity reduction and modified vertical gradient of gravity anomaly term. This is as follows;
G1=2Δgt+Δgp/2πκρ[∂Δg/∂h]p,
where
G1: G1 term at point P
Δgt : topographic correction in usual sense
Δgp: gravity anomaly at point P
k: = 6.67×10-8 dyne cm2/gr2
ρ: density of the material above sea level
[∂Δg/∂h]p: modified vertical gradient of gravity anomaly obtained by Numerov's formula using the surface gravity anomaly. Some discussins are given about the accuracy of the various practical formulas to obtain [Δ∂g/∂h]P. In any case, short wave length term in the distribution of gravity anomaly should be exactly known in order to obtain high accuracy.View full abstractDownload PDF (1374K) -
Takeshi DAMBARA1970 Volume 16 Issue 3 Pages 127-136
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSLong-period change in mean sea level in Japan is studied by removing linear secular change in the earth's crust and in mean sea level from observed mean sea level. Tendency of long-period change of northern sea area (north of the latitude 35°) is nearly the same as that of southern sea area (south of the latitude 35°), so the mean of all Japan areaa is used for the study. Power spectrum of long-period change is shown in Fig.5. This spectrum shows prominent periods as follows: 6.1 years, 8.6 years, 11.0 years, 13.1 years, 17.9 years, 20.3 years. Combining 17.9 and 20.3 years as 18.6 years, amplitude of each periodic change is determined. These are shown by (A1, A2), (B1, B2.), (C1, C2), (D1, D2) and (E1, E2 in eq. (6). The result is summarized in Fig.6, and is compared with mean longitude of moon's ascending node, and with sun's spot activity. It is concluded that the amplitude of 18.6-year astronomic tide in Japan is too small to be detected by the following reasons: 1) The deduced amplitude is not so certain compared with its standard deviation. 2) Phase difference from the moon's longitude is too large. 3) In the power spectrum, 18.6-year's peak is not directly seen, but two peaks of 17.9 and 20.3. Relation between 11.0-year tide and the solar activity is not certain, too. Longperiod tides of the apparent 6 periods deduced in the present paper may correspond to oceanographical and climatological changes.View full abstractDownload PDF (1031K) -
Noriaki SUDA1970 Volume 16 Issue 3 Pages 137-147
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSThe most effective factor to determine the accuracy of the electro-optical measurement is the temperature measurement along light path. At present the means of temperatures at terminal points on .the ground are used for the meteorological correction of EDM. In this case the radiation effect from the ground is so effective that it is difficult to gethigh accuracy more than 2×10-6. Generally to eliminate the radiation effect, it is recommended to construct high tower more than 10 m for getting accurate meteorological data. This paper deals with the relation between the observed daily distance variation with Geodimeter 8 and the temperatures of every 100m height interval which are determined from the empirical formula. Results are as follows. (1) The measurements, few hours before and after the sunrise and sunset are desirable, if the temperatures at 1.5m height are used. (2) Around discussed areas the meteorological observations at about 100 200m height are desirable for all day's measurement. (3) It is possible to get the high accuracy of order 1×10-6-2×10-6 from conducting the continuous temperature measurement at ground.View full abstractDownload PDF (794K) -
Minoru TANAKA1970 Volume 16 Issue 3 Pages 148-161
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSAn energy transfer in the earth due to the instability of the cross current (or field) in hydromagnetic approximation which shows one of the anomalous diffusion process of particles is treated, discussing the convections in both the core-mantle interface and the mantle. Effective diffusion coefficient which is derived from the present theory is seemed to agree with the diffusion coefficient due to the motion of diffusion carriers given by the theory of solids. Therefore, the energies of the convections and heat flows are estimated in the above two layers individually. As a result of these order estimation, it is suggested that the gravitational energy may be first transformed into the rotational energy of convection in core-mantle interface and then this energy may be transferred to the mantle convection energy. The frequencies of the scales of Chandler wobble and polar wandering are also suggested to be caused by the cross current (or field) instability in core-mantle interface and lower mantle, respectively. This paper discusses the problem of the energy transfer in the earth basing on the standpoint of space science.View full abstractDownload PDF (1663K) -
[in Japanese], [in Japanese]1971 Volume 16 Issue 3 Pages 162
Published: February 25, 1971
Released on J-STAGE: September 07, 2010
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Naomi FUJITA1971 Volume 16 Issue 3 Pages 163-166
Published: February 25, 1971
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (286K) -
Geographical Survey Institute1970 Volume 16 Issue 3 Pages 167-168
Published: February 25, 1971
Released on J-STAGE: July 05, 2011
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Hiromiti SUZUKI1971 Volume 16 Issue 3 Pages 169-171
Published: February 25, 1971
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSSince 1955, the Geographical Survey Institute has carried out several international gravity mea surements with the G.S.I. pendulum apparatus. The Western Pacific Calibration Line project was commenced in 1965 and since then six international observations have been completed with the modified G.S.I. pendulums. Using results of these observations, the gravity value at Tokyo was deduced and hitherto adopted value was examined which had been determined by Borrass in 1911 and is still the reference value in Japan. For this purpose, it is necessary to assume gravity values at occupied foreign stations. The International Gravity Bureau published the gravity values at the first order stations in 1959. But we have new pendulum values at many stations including the first order stations obtained with the Gulf-Wisconsin pendulums and also with the Cambridge pendulums. These results are independent of our results. Based on their gravity values at the same stations, gravity value at Tokyo old pendulum site was obtained. Results are summarized in the following Table.View full abstractDownload PDF (236K) -
[in Japanese]1971 Volume 16 Issue 3 Pages 172
Published: February 25, 1971
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (140K)
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