The Canadian Space Agency kindly provided us with 22 RADARSAT SAR scenes of regions that we selected in the waters of Australia, Papua New Guinea and Indonesia where we have oceanographic work underway, or where we have worked and have a feeling for the main oceanographic features.

Many of the scenes gave exciting new oceanographic insights, particularly when combined with data from other tools, such as ships, moorings, drifters and other satellites. Others were difficult to interpret, being dominated by meteorological effects.

In 1997/98 the Sepik River in northern Papua New Guinea was the focus of an international study TROPICS (Tropical Rivers Ocean Processes in Coastal Settings) to gauge the effects of sediment-laden tropical river plumes on the coastal seas and seafloor. RADARSAT SAR showed: the response of the plume to the reversing monsoon winds and underlying currents; wind and current wakes behind the offshore volcanic islands; and the arrangement of the river banks and coastal marsh systems. RADARSAT was unique in giving a large area, but fine resolution, view of a complex system in the cloudy tropics. It aided the interpretation of more conventional data.

In previous studies with NOAA AVHRR we have found that the rapid throughflow of warm water past the island of Penida in Lombok Strait induces upwelling in its lee and vortices up to 100 km downstream. RADARSAT SAR similarly revealed energetic throughflow patterns that extended ~100 km southward into the Indian Ocean. The flow generated extensive areas of rough water in the strait, no doubt well-known to local mariners, but never mapped synoptically. The scenes also showed the surface expressions of internal waves.

Australia's North Rankin oil and gas field comes under the influence of energetic currents associated with internal waves generated near the continental shelf edge. These influence the day to day operation of the production platforms and can cause scouring beneath seabed pipelines. We anticipate learning more about the internal waves through interpreting, with industry colleagues, in situ current data at the time of a RADARSAT scene showing the surface expressions of a rich field of internal waves.

One of our earlier scenes with ERS-1 SAR suggested that undular and V-shaped features on the ocean surface above the continental slope and shelf off eastern Australia near 31 S were expressions of transverse and oblique internal waves caused by the influence of seamounts and canyons on an energetic East Australian Current (EAC). In five other scenes, however, the internal wave expressions were absent, probably because the EAC was either not strong, or had meandered far out to sea. With RADARSAT our experience was similar: only one of several SAR scenes revealed a hint of the type of surface expressions that we associate with the rapidly changing bottom topography. The RADARSAT scene also revealed the edge of the EAC as a broad band of confused seas that we often experience on our research vessels. The same scene revealed smooth seas nearshore associated with coastal upwelling and from some headlands there were thin slicks up to 40 miles long.

Scenes of two remote oceanic islands, Christmas in the Indian Ocean and Heard in the Southern Ocean, showed refracting swells. Christmas had a wind shadow from the SE trade winds. Heard had two long and broad "wakes" of enhanced rather than reduced sea surface roughness, one to the NE and one to the SE.

Orbit 8007 17 May 1997 Sepik River PNG, SE monsoon	Orbit 9036 28 Jul 1997 Sepik River PNG, SE monsoon	Orbit 9379 21 Aug 1997 Sepik River PNG, SE monsoon	Orbit 12123 1 Mar 1998 Sepik River PNG, NW monsoon
Orbit 8837 14 Jul 1997 Lombok Strait, Indonesia	Orbit 9180 7 Aug 1997 Lombok Strait, Indonesia
Orbit 9480 28 Aug 1997 North Rankin oil and gas field, Western Australia	Orbit 11881 12 Feb 1997 North Rankin oil and gas field, Western Australia	Orbit 11995 20 Feb 1998 Laminaria oil and gas field, Timor Sea
Orbit 8800 12 Jul 1997 Cape Byron-Evans Head, northern NSW	Orbit 9143 5 Aug 1997 Cape Byron-Evans Head, northern NSW	Orbit 11887 13 Feb 1997 Cape Byron-Evans Head, northern NSW
Orbit 8921 20 Jul 1997 Central-north NSW	Orbit 9264 13 Aug 1997 Central-north NSW	Orbit 12008 21 Feb 1998 Central-north NSW
Orbit 8821 13 Jul 1997 Pt Stephens-Jervis Bay, central NSW	Orbit 9164 6 Aug 1997 Pt Stephens-Jervis Bay, central NSW	Orbit 9094 1 Aug 1997 Indian Ocean, Perth, Western Australia	Orbit 9437 25 Aug 1997 Indian Ocean, Perth, Western Australia
Orbit 9524 31 Aug 1997 Heard Island, Southern Ocean	Orbit 9479 28 Aug 1997 Fly River delta, PNG	Orbit 9166 6 Aug 1997 Christmas Island, Indian Ocean