how do the deep current and surface current flowing north along west coast of south africa differ
The deep current and surface current flowing north along the west coast of South Africa differ in various ways, including their origin, flow direction, depth, temperature, and speed.
1. Origin: The deep current, known as the Benguela Current, originates from the Antarctic Circumpolar Current (ACC), while the surface current, known as the South Atlantic South Equatorial Current (SASEC), originates from the Equatorial Current System.
2. Flow direction: The deep Benguela Current flows from south to north along the west coast of South Africa, while the surface SASEC flows from east to west, driven by the trade winds.
3. Depth: The deep Benguela Current extends to greater depths compared to the surface SASEC. The Benguela Current reaches depths of several hundred meters, while the surface current is constrained to the uppermost layer of the ocean.
4. Temperature: The Benguela Current is a cold current originating from the southern high latitudes. It brings cool, nutrient-rich waters to the surface, resulting in lower sea surface temperatures along the west coast of South Africa. In contrast, the SASEC is generally warm, transporting warm surface waters from the equatorial regions.
5. Speed: The Benguela Current is relatively slow-moving with average speeds of about 10-30 centimeters per second. The surface SASEC, on the other hand, can reach an average speed of around 50-70 centimeters per second, driven by the stronger trade winds.
Overall, the deep Benguela Current and surface SASEC differ in their origin, flow direction, depth, temperature, and speed, contributing to different ecological and climatic conditions along the west coast of South Africa.