Indian Ocean Margins

Abstract

The Indian Ocean is smaller in size (covering an area of 48 × 10⁶km² excluding its Antarctic sector; Tomczak and Godfrey 1994), but it is more complex and poorly understood oceanographically than the Atlantic and Pacific Oceans. The complexity owes to its peculiar geographical setting: its northern expanse is limited by land just north of the Tropic of Cancer. This has important consequences for both surface and subsurface circulations, the former because of the unique seasonal reversal of winds (arising from differential heating and cooling of the land and the sea), and the latter due to constrained subsurface water renewal in the north (related to the absence of temperate and polar areas). The altered circulations, in turn, profoundly impact biogeochemical processes along the ocean margins, an overview of which is provided in this section. Of the three boundary environments of the Indian Ocean dealt with in this chapter, viz. the monsoon-affected north Indian Ocean (by Naqvi et~al.), the Agulhas Current region (by Baird) and the western Australian shelf (by Feng and Wild-Allen), this section will focus more on the first, because it is not only the best studied but arguably also the most important in terms of the continental margin fluxes.