Mass and heat transport in the Argentine Continental Shelf

This paper investigates the barotropic circulation and its seasonal evolution in the area of the Argentine Continental Shelf extending between 40 and 50° S latitude. The study area has been divided into 66 elements of 1 x 1° and depth-integrated equations of mass- and heat-conservation have been set up for each of them. This procedure leads to a system of 124 equations with an easily understandable solution. The results obtained generally show a N-NE flow with a maximum speed of 10 cm s−1 which advects heat excess from the atmosphere. A strong seasonal signal is apparent in the circulation, with stronger (weaker) northeastward (variable) flow during the austral summer and autumn (winter and spring). The derived velocity field is almost independent of the value of the horizontal diffusion coefficient for KH varying between 0 and 103 m2 s−1. Model runs are presented for KH = 0 without diffusion) and KH = 102 m2 s−1 for both the yearly averaged and seasonal cases. Theoretical estimates of the mean annual circulation, and particularly the circulation calculated for summer and autumn, are in good agreement with observations made in the area and theoretical estimates obtained from rather sophisticated numeric models.