158 



Salinity of the Ocean, its Variation in Oceanic Space and in Time 



Table 71. Monthly mean values for T and S in the homogeneous top layer in the East 

 Sebirian Sea, Nov. 1922-Oct. 1923 



Depth 

 (m) 



1922 



Nov. 



Dec. 



1923 



Jan. 



Feb. 



Mar. 



Apr. 



Temp. °C 



Salinity (%„) 





 10-30 





 10-30 



-1-63* 

 -I-6I2 



29-45 

 29-50 



-1-61 

 -1-62, 



29-56 

 29-50 



-1-60 

 -1-593 



28-99 

 29-23 



-1-57 

 -l-59o 



29-21 

 29-20 



-1-58 

 -I-6O0 



29-28 

 29-36 



-1-57 

 -I-6O5 



29-49 

 29-46 



* Minimum; j Maximum 



The annual variation in the surface salinity in an adjacent sea depends very largely 

 on whether it has a humid climate with a large inflow of fresh water from rivers and 

 from precipitation, or whether it is in an arid climate with little fresh-water gain but 

 with a high evaporation rate. The latter type of adjacent seas with high salinities show 

 only a small annual variation, since the evaporation has very little effect on the surface 

 salinity; in the first type, on the other hand, the annual range may reach relatively large 

 values. The annual surface salinity variation at the Adlergrund hght-ship in the south- 

 western part of the Baltic is presented as an example (Neumann, 1938) (Mean monthly 

 values for the period 1926-35) in Table 72. 



Table 72. Annual surface salinity variation at the Adlergrund light-ship (Baltic Sea) 

 and total fresh-water inflow into the Baltic 



• Minimum; t Maximum 



These values follow almost exactly a pure sine curve 

 S = 7-41 + 0-103 sin | ^ t + 66-8 | + 0-006 



l-^ t + 66-8 j + 0-006 sin I - 



/ + 15-4' 



with a maximum in January-February and a minimum in July-August. The most 

 important factor affecting the amount of salinity in the Baltic is the inflow of fresh 



