Wave monitoring
Ships, oil platforms and offshore wind farms are threatened by rough seas.
Information provided by radar satellites can support the detection and forecast of extreme wave heights.
From ESA
Within the first days of its operational life, the Sentinel-1A satellite has provided data for marine services in the Arctic.
During the first week of the satellite’s operational data supply, experts from the Technical University of Denmark and the Danish Meteorological Institute working under the Horizon 2020 MyOcean Follow-On project used the data to alert vessels on marine ice conditions.
Sentinel-1 delivers radar imagery for numerous applications.
Images acquired over the ocean are essential for generating timely maps of sea ice for safe passage as well as for detecting and tracking oil spills.
The mission also offers key information on wind and waves in the open sea for shipping and wave-energy applications.
Images acquired systematically over land mean that ground movement barely noticeable in everyday life can be detected and closely monitored.
As well as being a valuable resource for urban planners, this kind of information is essential for monitoring shifts from earthquakes, landslides and volcanic uplift.
Moreover, Sentinel-1 is designed specifically to provide images for rapid response to disasters such as floods and earthquakes.
Its primary objective is to provide forecasts of the global marine environment and the near-realtime observation data necessary for forecast models.
Since Sentinel-1A data started to become free and accessible earlier this month with the satellite entering into its operational phase, the Danish Meteorological Institute began to use the information to improve observations of the polar regions and forecast maritime conditions.
The data are being used to produce ice charts, showing the details of ice conditions in a variety of regions, including the warnings of icebergs drifting in shipping routes.
Monitoring ice drift
This mosaic of Sentinel-1A data from 10 October 2014 shows ice drift vectors derived from Sentinel-1A scenes acquired on 9 and 10 October (red), along with MyOcean ice drift forecasts for 10 October (yellow).
The PolarView browser allows the visualisation of Copernicus marine core service MyOcean forecasts, as well as observational data from a large number of satellite data sources.
The first ice chart from Sentinel-1A was produced in demonstration mode in April just weeks after launch, demonstrating the satellite’s capabilities for ice mapping at an early stage.
Now that the satellite is operational, the mission will gradually become the backbone to the regular ice charting of Greenland waters.
Monitoring icebergs
The capability of Sentinel-1A to detect icebergs during all weather conditions is improving maritime safety. The satellite’s radar gathers information in either horizontal or vertical radar pulses, and colours can be assigned to the different types.
In this image acquired near Greenland’s Jakobshavn Glacier on 26 April 2014, sea ice appearing blue-green can be distinguished from icebergs in pink.
The radar on Sentinel-1 can see through clouds and in the dark, making it the perfect tool for monitoring polar regions that are prone to bad weather and long periods of darkness.
This image is an example of an ice chart from 8 October 2014, with red depicting sea ice cover.
The radar can distinguish between the thinner, more navigable first-year ice and the hazardous, much thicker multiyear ice to help assure safe year-round navigation in ice-covered Arctic and subarctic zones.
The mission also provides continuous sampling of the open ocean, offering information on wind and waves.
This is useful for understanding interactions between waves and currents, forecast iceberg drift and improve efficiency for shipping.
In addition, these observations can be used to track the paths of oil slicks and other pollution.
Ice charts are the primary means of providing near-realtime ice information to mariners, and are traditionally drawn manually from satellite data. The first Sentinel-1A ice chart was drawn from an image acquired at 10:10 GMT on 26 April 2014.
“There are a lot of expectations for Sentinel-1,” said Leif Toudal Pedersen, from the Danish Meteorological Institute.
“This mission will be the backbone of future ice charting and ice service provision, as well as sea ice science development.”
User-friendly, near-realtime access to Sentinel-1 data for marine users in polar regions is provided by PolarView and the DMI Centre for Ocean and Ice.
The current MyOcean-Follow On H2020 project comprises 58 European public and private partners from 28 countries, and is led by Mercator Ocean.
Links :
- GeoGarage blog : Earth observation enters next phase
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