Oceanic dynamics was traditionally investigated by sampling from instruments in situ, yielding quantitative measurements that are intermittent in both space and time; the ocean is undersampled. The need to obtain proper sampling of the averaged quantities treated in analytical and numerical models is at present the most significant limitation on advances in physical oceanography. Within the past decade, many electromagnetic techniques for the study of the Earth and planets were applied to the study of the ocean. Now satellites promise nearly total coverage of the world's oceans using only a few days to a few weeks of observations. Both a review of the early and present techniques applied to satellite oceanography and a description of some future systems to be launched into orbit during the remainder of this century are presented. Both scientific and technologic capabilities are discussed
