HYDROLOGY OF THE BRANSFIELD STRAIT 



13 



Joinville Island and reaches about as far as Trinity Island, where it meets the slight 

 north-east set from de Gerlache Strait in Orleans Channel between Trinity Island and 

 Graham Land. The effect of the cold dense Weddell Sea water towards the north-east 

 end of the Bransfield Strait and on the Trinity Peninsula side is such that all or 

 practically all traces of the temperature inversion due to the warm deep water, which 

 usually lies immediately below the colder Antarctic surface water, have disappeared 

 from Sts. 197, 198, 199, 200, 201, 204, 205 and 206, which are enclosed in the shaded 

 area in Fig. 7. 



The difference between the water on either side of the strait is emphasized in this 

 series of observations because the water on the north-west side of the strait has been 



Fig. 7. The stippled patch shows the area in April 1927 in which no thermal evidence of the 



warm deep water was present. 



warmed more by the sun than that on the south-eastern side, which is much colder 

 and has its origin in the Weddell Sea. In winter this difference of temperature of 

 the surface waters in these currents would not be shown to such an extent owing 

 to surface cooling and vertical mixing. In midsummer in calm weather a discontinuity 

 surface is sometimes found with a temperature difference of over 2 C. between the 

 surface and a depth of 10 m. 



Considerably less saline surface water is to be seen in and south-west of the de Gerlache 

 Strait, and this water shows a very striking contrast with the heavy colder surface water 

 farther to the north-east along the coast of Graham Land and Trinity Peninsula. 



