736 EIGHTH PACIFIC SCIENCE CONGRESS 



We now eliminate the effects of the statical pressure from the 

 residual sea-level variation at Kushimoto. The correlation coefficient 

 between h^ and this quantity 



r = 0.61 (n = 7) 



is not significant. However, when we further deduct h^ from this quan- 

 tity, the correlation between h^. and the last quantity is significant at 

 the level of 2%, since we have 



r = 0.84 (n = 7) 



It means that the residual sea-level change in this period is chiefly 

 caused by the variations of pressure, water density, and ocean currents. 



7. Meteorological Effects 



(i) Pressure— The pressure change naturally causes the variation 

 of the sea-level. The sea-level rise of 1 cm. nearly corresponds to the 

 pressure fall of 1 mb. The fluctuation of the annual mean sea-level 

 is generally within 1 mb. and the corresponding sea-level change will 

 be also the order of 1 cm. or less. 



(ii) Winds— According to Shimizu (11), the sea-level change caused 

 by winds is estimated to be the order of 1 cm/m/sec or less for the 

 most effective wind directions. Therefore, the wind effects will be 

 disregarded for our purpose, since the fluctuation of the annual mean 

 wind speed is within tens of centimeters. 



Effects of other elements (precipitation, melting of polar ice, etc.) 

 are supposed to be too small to be taken into account. 



8. Conclusions 



(i) The annual mean sea-level at the stations along the Japanese 

 coasts make the progressive and periodic variations. The progressive 

 changes are within 1 cm/year excepting Osaka (6 cm/year), and the 

 periodic changes (9.3, 11.5 and 18.6 years) have the magnitudes with- 

 in a tew centimeters. 



(ii) The progressive changes are chiefly caused by the vertical land 

 deformation: the periodic changes are likely to be chiefly caused by 

 astronomical, oceanographical, and meteorological origins. 



References 



1. Land Survey: Tidal Record, 1900-29 (1930). 



2. Geogi-aphical Sui-vey Institution: Tidal Record, 1930-49 (1950). 



3. Imperial Marine Observatory: Tidal Observations, Vol. 1-18, 1924-41. 



4. Central Meteorological Observatory: Tidal Observations, Ser. 2, 1941-48, 



Ser. 3, 1949-. 



5. M. Ogawaka: Applied Statistics, Chapter 7 (1949). 



