Airbus Defence and Space

ASAR offers a coverage of over 400 km

The imaging radar instrument uses microwave radiation to image the surface of the Earth and the oceans

The Advanced Synthetic Aperture Radar (ASAR) is an imaging radar instrument which uses microwave radiation to image the surface of the Earth and the oceans. As well as penetrating clouds, it also works at night and in all weather conditions. ASAR is particularly suited to various maritime applications. For example, it recently began recording global data on high ocean swells which pose a risk to shipping. The data can be accessed in near-real time, enabling scientists to forecast dangerously high breakers on the world’s oceans. ASAR data can also be used to retrieve the near-surface wind field, which aids in the issuing of both shipping warnings and weather forecasts.

 

The largest of Envisat's instruments is the Advanced Synthetic Aperture Radar (ASAR).

ASAR emits microwaves which bounce off the surface before returning to the radar. The radar echoes provide detailed information about the surface, for example on the roughness of the terrain. Scientists can use this data to locate oil spills in mid-ocean. This technology was thrown into the spotlight in April 2010 when the Deep Water Horizon oil rig exploded in the Gulf of Mexico, causing oil to flow unchecked from the ruptured well in the ocean floor. ASAR was able to track the spread of the oil across the sea’s surface day and night through the clouds and determine which direction the spill was being driven by the currents. This information helped the authorities to take countermeasures and to provide a steady flow of information to people in the affected coastal regions.

Deep Water Horizon: ASAR was able to track the spread of the oil across the sea’s surface day and night.

ASAR also assists with data gathering in the polar seas, for example by providing data on pack ice and free-floating icebergs in the polar regions. This information has been available to shipping companies for a number of years, and a new interactive website now offers the option of accessing the data in real time. The project, which is called Polar View, is an important component of the GMES programme.

ASAR attracted particular attention in the summer of 2010 with the release of images showing the calving of a giant iceberg from the Petermann Glacier in north-west Greenland. ASAR tracked the path taken through the ocean by the iceberg over a period of several weeks. The iceberg was the largest in the northern hemisphere at that time, covering a surface area of approximately 100 square miles.

The calving of a giant iceberg from the Petermann Glacier in north-west Greenland

Researchers have just recently hit upon an unexpected additional use for ASAR data. Coniferous boreal forests cover some 15% of the Earth’s land area and make up approximately one third of the world’s forests. This makes them a key climate factor in the global carbon dioxide cycle – yet scientists have struggled to map their total biomass with anything like the required degree of accuracy. As part of the BIOMASAR project, European scientists developed a new method of evaluating ASAR data to create more accurate maps. Based on 10 years of ASAR data and the planned continuity of this data supply in the form of Sentinel 1, scientists now have the resources to create a large-scale boreal forest biomass inventory and to carry out long-term monitoring of the changes in the carbon dioxide sink provided by forest biomass.

Synthetic Aperture Radar Interferometry and the first ever image

 

SCIAMACHY MIPAS GOMOS Advanced Synthetic Aperture Radar ASAR AATSR
      SCIAMACHY           MIPAS          GOMOS           ASAR           AATSR

 

EnvironmentEnvisat