Journal of the Geodetic Society of Japan
Online ISSN : 2185-517X
Print ISSN : 0038-0830
ISSN-L : 0038-0830
Volume 32, Issue 3
Displaying 1-7 of 7 articles from this issue
  • Torao TANAKA
    1986 Volume 32 Issue 3 Pages 167-173
    Published: November 25, 1986
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    Excess path delays due to water vapor were calculated using the data observed in February 1982 at 20 routine radio zonde stations which are given in the Aerological Data of Japan. Mean delays in the zenith direction in February are 2-3, 3-5, 5-7 and 10-15 cm in Hokkaido, northeastern Japan, south-western Japan and Bonin and Ryuku Islands, respectively. Standard deviations from these mean delays are 1, 2-3, 3-4 and 4-5 cm, respectively. The mean delays ΔLw are expressed by the surface temperature Ts at the stations as ΔLw =ΔLw0 exp (αT8) with ΔLw0=4.0 and α=0.075: This relation holds also to the seasonal variation of excess path delay at Wajima, so that the relation will hold at anytime anywhere in Japan. Simple interpolations of the present data show that excess path delays may be estimated with a precision better than 1 cm by employing the routine radio zonde observations.
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  • Teruyuki KATO, Ichiro MURATA, Atsushi TSUCHIYA
    1986 Volume 32 Issue 3 Pages 174-180
    Published: November 25, 1986
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    Electrons in the ionosphere delay the arrival of the wave radiated from the GPS satellites, which cause a substantial excess path. For differential GPS, the difference of the excess path at the both ends of the baseline makes one of significant error sources for higher accuracy in determining baseline vector. Such delay may be corrected directly by observing total electron content (TEC) or the critical plasma frequency (f0F2) at the site as an alternate quantity. Temporal changes of the correlations between these values are examined using the data obtained by Radio Research Laboratory at Kokubunji, Tokyo. The results show that the correlation is rather high in the winter time than in the summer time. Rough estimates of the spatial change of the excess path are also made by using both f0F2 and TEC. Simple calculations indicate about 4 cm differences in excess path for 10 km baseline, for both f0F2 and TEC.
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  • Mohamed G. EL-IBIARY
    1986 Volume 32 Issue 3 Pages 181-190
    Published: November 25, 1986
    Released on J-STAGE: July 05, 2011
    JOURNAL FREE ACCESS
    The gravity anomaly distribution in and around Japan was used together with the explosion seismic data in order to trace the Mohorovicic discontinuity along the northeastern Japanese arcs. The present paper represents the application of Talwani's method along several profiles-chosen to be perpendicular to the Pacific trench axisassuming that the crust consists of a single homogeneous layer and the density contrast Δρ =0.38 g/cm3 between the crust and upper mantle. A contour map is drawn using the calculated depths of Mohorovicic discontinuity. It shows that the crustal thickness varies between 24-31 km, 28-32 km, 30-34 km and between 33-35 km in Hokkaido, Tohoku, Kanto and Chubu areas respectively.
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  • -Earth Tide Analyses-
    Kachishige SATO, Tadahiro SATO, Seiitu TSURUTA, Ryuichi SHICHI
    1986 Volume 32 Issue 3 Pages 191-202
    Published: November 25, 1986
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    This paper describes a result of tidal analyses of tilts observed with two kinds of water-tube tiltmeters at the Esashi Earth Tides Station, and discusses the revealed periodic variations on the amplitudes and phase differences of major tidal constituents. Both the amplitudes and phase differences of major tidal constituents (Q1, O1, K1, N2, M2 and S2) obtained from the records of each tiltmeter for the period from April, 1980 to September, 1982 were very close each other, and were also very consistent with those presented in the previous paper. A clear seasonal or annual variation was distinguished not only on the amplitudes but also on the phase differences for several tidal constituents. The most typical pattern was found out on the M2 constituent of the EW component. Almost the same pattern of annual variation on the ocean tides near the Esashi Station, and the coincidence in phases of amplitude changes among the tilts and ocean tide suggested an effect of the ocean load upon the solid earth. An estimation of this effect made by using the Green's function given by Farrell against the Gutenberg-Bullen's Amodel accounted for just half of the observed amplitude variation of about 0.3 mseca/cm.
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  • Tsutomu SAITO
    1986 Volume 32 Issue 3 Pages 203-213
    Published: November 25, 1986
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    The statistical structure, the iterative method, and the structure of the covariance matrices in the adjustment of free networks are reviewed .
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  • Tsutomu SAITO
    1986 Volume 32 Issue 3 Pages 214-223
    Published: November 25, 1986
    Released on J-STAGE: July 05, 2011
    JOURNAL FREE ACCESS
    In the sense of mathematics, we show that the planar adjustment of triangulation and trilateration in free networks yields the centroid solution. We also construct formulas for the adjustment of free networks with specific constrained conditions.
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  • Fumiaki KIMATA
    1986 Volume 32 Issue 3 Pages 224-225
    Published: November 25, 1986
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    In order to improve the method of electrooptical distance measurements, the six temperature deviation at the 95% confidence level around sunset was calculated from the air-temperature observations in a boundary layer at Tsukuba, 1981. The minimum deviation less than ±0.5° was observed for 30 minutes before sunset up to 50 m above the ground through the year. If ten-day mean temperature is adopted, the deviation is less than ±0.5°C for a wide range of hight from 0 m to 100 m.
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