A steady state model of the Somali current

Abstract

A steady state model of the Somali current including forcing by both the curl and the divergence of the wind stress is discussed. The model equations are linear, but the results presented are for the one nonlinear case. The grid resolution was 12 km in the zonal and 24 km in the meridional direction. The streamfunction and velocity potential of the current are presented for forcing by divergence and compared with a situation when only the curl is present. The results indicate that a two-gyre system appears in July, a representative month for the summer monsoon, only when divergence is included. Computations with available data indicate that the divergence is comparable in magnitude to the curl near the location of the Somali current. The model produces three other important features: (i) strong upwelling off the east coast of Africa, (ii) downwelling over central Arabian sea and (iii) a strong eastward current in the upper layer towards the interior of the Arabian sea near 12°N.