Introduction

The growing human activities in the Polar Regions, as well as increasing concern for the environment, require good sea ice maps on large scale, in regions and in specific locations. Sea ice is also a critical parameter to monitor in order to detect a possible global climate change. Passive microwave data from satellites has been used for nearly two decades to monitor regional, seasonal and interannual variability of ice extent and concentration, as shown by the SSM/I ice map.

The figure shows the typical extent of sea ice in the winter and summer based on passive microwave data (SSM/I) from satellites.

However, a detailed monitoring of sea ice characteristics was not possible until the launch of ERS-1. The possibility to monitor sea ice independent of daylight and cloud cover has now improved considerably. The ERS-1 SAR data is an important new source of information for improved understanding of sea ice behaviour.

In several regions of the Arctic there is a need for accurate ice maps for marine activities such as fisheries, offshore oil exploitation, ship transportation and research expeditions. In the Barents Sea and the region around Svalbard, a rich marine life is the base for extensive fisheries by several countries.

Additionally, oil and gas production is moving farther north into the seasonal ice zone both in the eastern and western hemisphere. The sea ice conditions impose severe restrictions on these activites. Regular access to high quality satellite observations will improve the ice mapping and contribute to safer operations in the Arctic.

The large-scale and regional ice mapping in the Arctic is the responsibility of national ice centres in the countries surrounding the Arctic. SAR data from ERS-1 have been introduced in these ice centres and serve as an important supplement to other data. SAR data have also been demonstrated in special monitoring and forecasting services for offshore operations and ice navigation and other applications as shown in the following examples.

All the informations that follows has been provided by Stein Sandven, Åsmund Drottning, Tor Olaussen and Lasse H. Pettersson from the Nansen Environmental and Remote Sensing Center (NERSC - Norway)

With contributions from :
Terra Orbit A/S, Norway
SMHI, Sweden
DMI, Denmark
AWI, Germany
IFREMER, France
CCRS, Canada
ICEC, Canada
NIC, USA

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry