706 EIGHTH PACIFIC SCIENCE CONGRESS 



Climate in the Sea 



Seasons can be defined in the sea (Fig, 3) just as they are in the 

 atmosphere. Summer is that period when water temperatures are at a 

 maximum, which in the northern hemisphere occurs in the month of 

 August. Winter is the season when they are at a minimum, usually 

 December and January. Spring and autumn are the transition periods 

 from these two extremes. The extremes and durations of these marine 

 seasons differ from year to year due to changing atmospheric conditions. 

 That is why these daily seawater records are so valuable. It is only by 

 reference to these records that the scientist is able to measure just how 

 great the annual variation has been. The daily seawater records will 

 show these annual changes more clearly than meteorological data be- 

 cause they reflect the combined effect of the varying atmospheric factors 

 of solar insolation, wind, rainfall, and land drainage. 



Along such an extensive coastline as British Columbia, there are 

 several different types of oceanic regions. The locations of the water 

 sampling stations have been chosen so that the various types of regions 

 are all being recorded by daily surface observations. The annual range 

 of seawater temperature varies from station to station and this differ- 

 ence in annual temperature range is a criterion to the type of region 

 being observed. For instance, in Figure 4, I.angara shows an annual 

 temperature range of 10°F, typical of an exposed open ocean region; 

 Kains shows a slightly higher annual range of 1 1°F, typical of an exposed 

 coastal region; Entrance shows a high annual range of 18°F, typical of 

 a protected coastal region; and Race Rocks shows a low annual range 

 of 6°F, typical of a region of great turbulence. 



The annual salinity cycles observed at the various seaw^ater sampling 

 stations (Fig. 4) are typical of three climatic regions. Summer salinity 

 maxima (Kains) are due to coastal upwelling and low summer precipi- 

 tation with little subsequent fresh water runoff. The degree of coastal 

 upwelling is governed chiefly by the force and duration of winds blow- 

 ing offshore during the summer. In these latitudes, the winds are never 

 in a continuous steady state, and assessment of the degree of upwelling 

 from wind data alone would be quite difficult. Observation of the ef- 

 fect of these winds as indicated by the surface salinities is a much easier 

 matter. 



Fresh water runoff from the many large rivers that drain into the 

 Canadian Pacific area is at a maximum in the summer because of the 

 melting of snow at the sources of the rivers far inland. This effect is 

 demonstrated by a summer salinity minimum at all the sampling sta- 

 tions situated near the mainland coast, such as Entrance Island. Here 

 again, measurement of the combined effect of the ^arious atmospheric 



