HARBOR ANALOG SYSTEM 
Part Il - TEMPERATURE STRUCTURE 
INTRODUCTION 
There are considerable published data concerning the factors 
which affect the surface water temperatures of the oceans, the trans- 
port of heat, and temperature change in the upper layers of the ocean. 
After all of the physical and dynamic processes relating environmental 
factors such as evaporation, radiation, cloudiness, wind velocity and 
turbulence are considered, the useful generality is that a high corre- 
lation between surface air and water temperature can be shown. This 
correlation, better in low latitudes where annual ranges of temperature 
are small, decreases toward higher latitudes. Since fresh water freezes 
at 32°F. and highly saline waters freeze at temperatures between 28° 
and 29°F., it is apparent that mean air temperatures which are colder 
than the sea surface freezing points may differ considerably from the 
water temperatures; however, the utility of mean air temperatures in 
forecasting water temperatures remains high because mean air temper- 
atures below 28°F. for a period of several days will produce ice or 
water temperatures in the range between 28° and 32°F. 
Since one of the main objectives of this report is to estimate the 
surface water temperature in any harbor on earth, it was thought that 
the use of H.O. Publication No. 225, “World Atlas of Sea Surface Temp- 
eratures.'' would be useful in approximating the surface temperature in 
nearshore waters. However, comparison of U. S. Coast and Geodetic 
Survey tide-station temperatures with the isotherms in this publication 
revealed these isotherms to be unreliable in nearshore areas, In con- 
trast, comparison of meanair temperatures fromthe “U. S. Navy Marine 
Climatic Atlas of the World” with surface water temperatures for the 
U. S. Coast and Geodetic Survey tide stations indicated a high corre- 
lation between the mean monthly air temperature and the average 
nearshore surface water temperature for the same month, The air- 
sea temperature difference is least in low latitudes where the annual 
range of mean monthly air temperature is small and becomes greater 
in higher latitudes where the annual range of air temperature increases. 
The average differences were relatively variable where the surface 
water temperature was influenced by fresh water river discharge or 
where tidal ranges were high. Inland water areas such as the harbors 
