DYNAMICS OF THE SOUTHERN OCEAN 



133 



by referring to only two tables, with very occasionally a small and simple adjustment 

 from a third table. The tables are drawn up for very small intervals of a, , temperature, 

 and depth, and the necessary interpolations can be made quickly. The tables also give 

 the anomalies to the sixth place of decimals, and since the temperature and salinity data 

 are probably accurate to o-oi° C. and o-oi °/ 00 the anomalies calculated from the tables 

 are likely to be correct to the fifth place of decimals. The anomalies at the standard 

 depths were obtained graphically by plotting those calculated for the thermometrically 

 measured depths against depth on a large-scale graph. 



The positions of the stations at which the observations were made and the ano- 

 malies of specific volume and dynamic depth are given in Tables II and III at the 

 end of the report. In order to save space the anomalies of specific volume are given 

 multiplied by io° and the anomalies of dynamic depth multiplied by io 5 . The anomalies 

 of dynamic depth can be used in equation (6) since the difference between the anomalies 

 at two stations is equal to the difference between the dynamic depths themselves, and 

 if they are expressed in terms of dynamic metres, with the distance between the two 

 stations L in kilometres, the current difference n — n x will be obtained in centimetres 

 per second. In order to facilitate the substitution of the data from Table III in equation 



(6) the values of 



2oj sin cf> 

 they are multiplied by io~ 4 



for latitudes of 30 to 8o° are tabulated below; to save space 



Table I. io- 4 /2o> sin <f> 



In Table IV, also given at the end of the report, the dynamic depths of the 0-5000 

 decibar isobaric surfaces in a sea of uniform temperature o° C. and density (a,) 28-00 

 are tabulated, so that the dynamic depths of the isobaric surfaces at any of the stations 

 given in Tables II and III can be obtained by adding the anomalies to these depths. 



The topographies of the o and 600 decibar surfaces relative to the 3000 surface, ob- 

 tained by subtracting o and the anomalies of dynamic depth of the 600 surface from the 

 anomalies of the 3000 surface, are shown in Figs. 1 and 2. The dynamic isobaths are 

 drawn at intervals of o-i dyn. metres and the heavy lines at intervals of 0-5 dyn. metres. 



The topographies have been determined relative to the 3000 surface, since at this 

 depth the meridional water movements with which this report is largely concerned are 

 likely to be weakest. Generally the deepest isobaric surface for which observations are 

 available is assumed to be level, but in the Southern Ocean the meridional movements, 

 at least, are probably not weakest near the sea bottom. The work of Defant (1935) in the 



