over intervals of several years through decades. Examples of applications in this 

 range are given below but none are for the higher frequencies such as current 

 variations as deduced by sea-level fluctuations (Garrett and Toulany, 1981 and 

 1982). 



A. Climate Monitoring 



The fields of geological oceanography and coastal engineering require relative 

 sea level for coastal processes investigations. But the atmospheric and geological 

 sciences require absolute sea level for their climate monitoring and vertical land 

 movement studies. They require separation of the eustatic and vertical land move- 

 ment components in the observed relative sea-level series. Since the observed rela- 

 tive sea-level series is subject to so many absolute interpretations, as expressed 

 in the preceding paragraph, some "anchoring" approach must be sought. 



The traditional method assumes that tide stations are equally distributed 

 throughout the Earth. The observed relative sea-level series or their trends are 

 meaned to give the eustatic component. The basic assumption of the method is not 

 valid, of course. Continents, with their shorelines for mounting traditional tide 

 gages, are not equally distributed throughout the Earth. Furthermore, tide stations 

 have been largely concentrated in the industrialized nations of Northern Europe, 

 North America, and Japan. Nevertheless, most of our eustatic rates come from 

 modifications of this method. Areas, unique in their sea-level signal coherence 

 (Roden, 1966; Hicks, 1972) and geological similarities (Gutenberg, 1941), are 

 weighted and averaged to compensate, hopefully, for the unfulfilled assumption. 

 Also, particular stations are frequently "favored" for their length of series, bench 

 mark control history, instrument care, exposure, and geological location (Lisitzin, 

 1958). 



Investigations using this general method, although varying greatly in detail, 

 have been summarized by Lisitzin (1974). Her conclusion, based on papers by 

 Gutenberg (1941), Lisitzin (1958), and Fairbridge (1961), among others (including 

 those considering cryologic estimates), is that the average eustatic increase 

 amounts to 1.0 to 1.1 mm per year. More recent findings are: Emery (1980), 3.0 mm 

 per year; Gornitz et al . (1982), 1.2 mm per year; and Barnett (in manuscript), 

 1.5 mm per year. Gornitz et al., Etkins and Epstein (1982), and Barnett have 

 correlated eustatic rates with glacial melting, air temperature, and ocean thermal 



