m m Satoshi SATO 48

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ゆゆこふじがわ
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1 REPORT OF HYDROGRAPHIC AND OCEANOGRAPHIC RESEARCHES No.46 March, 2010 Activities on Tides at Hydrographic Department in Meiji Era Satoshi SATO : Environmental and Oceanographic Division Abstract At the end of th Century, Japan Hydrographic Department adopted Indian Spring Low Water as the chart datum of Japanese charts. The reason why it was adopted was that the chart datum was able to be determined by the short term tidal observation. It was not examined whether the Indian Spring Low Water is suitable for Japanese chart datum or not, because Japan Hydrographic Department did not have enough knowledge on the tides in those days. a 47

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3 Activities on Tides at Hydrographic Department in Meiji Era Admiralty Manual of Scientific Enquiry Admiralty William Whewell Tides 49

4 Satoshi SATO Admiralty Charles Darwin Graphical Interpolation a 50

5 Activities on Tides at Hydrographic Department in Meiji Era 51

6 Satoshi SATO Charles Darwin George H. Darwin Admiralty Scientific Manual Admiralty Tides G.H. Darwin Scientific PapersOceanic Tides and Lunar Disturbance of Gravity A General Article on the Tides Scientific Papers Whewell G. H. Darwin G.H. Darwin M SKKOP G.H Darwin Indian Spring Low Water Mark Indian Spring Low Water Mark Indian Spring Low Water Mark A Hm Hs H Ho A Hm Hs H Ho Hm : M Hs : S H :K Ho : O a Datum Level 52

7 Activities on Tides at Hydrographic Department in Meiji Era G.H. Darwin Mean Low Water Springs Hm Hs H Ho Hm H Ho Hm Hs A Hm Hs H Ho G.H. Darwin Hm HsH Ho Hm Hs Mean Low Water SpringsNearly Lowest Low Water Hm Hs H Ho Hm Hs Hm Hs H Ho Hm Hs H Ho Hm Hs Hm H Ho Hm Hs H Ho Whewell G.H. Darwin 53

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11 Activities on Tides at Hydrographic Department in Meiji Era by Datum respecting tide level, The necessity for a statement by each country, showing the exact connection between the zero used for tidal predictions i.e., as given in the Tide Tables and that of the datum used on the charts. Datum for reduction of soundings, especially with reference to the necessity for a universal method for its careful selection. Tidal datum should be the same as chart datum, and should be a plane so low that the tide will not frequently fall below it. It is greatly to be desired that a uniform datum plane should be adopted by all nations, and the following rule is suggested for the further consideration of Hydrographers for a universal datum plane, which should be called International low water That the plane of reference below mean sea level shall be determined as follows : Take / the range between mean lower low water and mean higher high water and multiply this / International low water International low water IHB International Hydrographic Bureau Special Publication No No No No International low water 57

12 Satoshi SATO Special Publication No International low water International low water International low water 58

13 Activities on Tides at Hydrographic Department in Meiji Era International low water International low water Tidal datum should be the same as chart datum, and should be a plane so low that the tide will not frequently fall below it Special Publication No LAT : Lowest Astronomical Tide LAT LAT 59

14 Satoshi SATO LAT HAT : Highest Astronomical Tide HAT cm cm Admiralty Admiralty Manual of Scientific Enquiry, edited by Sir John F. W. Herscel, pp, Admiralty, London. Admiralty Admiralty Scientific Manual, Admiralty, London pp pp pp pp pp pp pp 60

15 Activities on Tides at Hydrographic Department in Meiji Era pp 61

16−ª1“ƒ-07‘¬ŠÑ

16−ª1“ƒ-07‘¬ŠÑ The purpose of this study is to clarify a process that Awa dance developed into tourist resources and the factors that it spread out in all over Japan. Consideration was made with the memory magazines,