Landsat data were used to observe variations in ocean colour in the south-western Tasman Sea adjacent to the Australian coast and in Bass Strait. These variations were interpreted as ocean-circulation patterns and these patterns were seen to be consistent with the known behaviour of the water masses in the area. The satellite data were displayed for interpretation as grey-scale and pseudo-colour images of individual bands of the raw data, as false-colour composites of three bands of the raw data, as thematic maps following multispectral classification, and as grey-scale and pseudo-colour images of data corrected for the effects of atmospheric radiance. These images were interpreted visually, appealing to the known characteristics of the satellite sensor and the typical spectra of upwelling ocean radiances.