During the different phases of
the lifecycle of an off-shore windmill farm satellite data can provide
valuable information about the environmental conditions found in a
specific area. Examples of such information are listed below.
Morphology analysis - coastline dynamics
Before
developing an off-shore windmill farm information about the coastal dynamics is needed in order to assess potential problems with
sedimentation, environmental impact in the coast as a result of the wind
farm construction etc. Coastline changes can be analysed approximately
forty years back in time based on different remote sensing data sets.
Recently declassified US spy satellite images provide a unique data
source for information about the stability of coastal environments. When
combined with modern high resolution satellite images, long time series
of coastal development can be analysed. The processing of US spy data
is relatively complex, but GRAS has expertise in processing these data
sets for coastal monitoring in many parts of the world. Typically, 4-5
images from the period 1960 - present are included to produce coastal
change maps with an accuracy of app. 15 metres. Recent years (1986 →)
allows accuracies within 5 meters by using SPOT imagery and very high
resolution data (2000 →) allows change mapping with accuracies of app. 1
meter, comparable to aerial photography.
Sediment distribution
The spatial
and temporal distribution of sediment in the marine environment can be
mapped by remote sensing. This information is important for
environmental impact assessment of the shoreline and to assess
sedimentation problems around the windmill structures. The sediment
affects the reflectance pattern of the water and the different levels of
reflectance registered by the satellite sensors can therefore be
converted to a measure of the level of suspended matter in the water
body. The presence of sediment in the water column is clearly visible in
the full resolution MERIS image covering the Bristol Channel shown
below.
Operational data for waterforecasting
In the
planning, construction and maintenance phases of offshore wind farm
operation it is important to be able to forecast ocean conditions such
as sea level and wave height. Remote sensing data are important for
validating these models and GRAS currently delivers validation input to
the DHI Waterforecast.
More information is available here.