Description:
Remote sensing techniques have been utilised since 1961 with
various types of sensors and applications in environmental and military
purposes. Soon enough the methodologies begun to include the monitoring
of marine biogeochemical parameters. Remotely sensed airborne or
satellite data can provide the necessary spatial perspective to
collect information about the sea surface characteristics and water
quality on a regional scale. Water quality parameters of interest
nowadays include ocean colour and chlorophyll concentration, detection
of algal blooms and oil spills and estimation of total suspended
solids.
Optical and multispectral sensors using advanced algorithms optimise
target reflectance and support quantitative measurements of the
above mentioned parameters with relatively coarse (500-1200m) resolution
and wide fields of view. Hyperspectral data (collected in many and
narrow ranges of the visible and infrared wavelengths) allow for
greater precision in characterizing target spectral signatures.
Monthly and seasonal imaging provides the data necessary for modelling.
SAR data can provide additional information on current, wave and
mesoscale features so as to observe trends over time when optical
data are not available due to periods of cloud cover.
However these applications have not been able to lessen the efforts
undertaken by marine scientists during in situ monitoring campaigns,
because the above mentioned parameters are only a small fraction
of those studied in the marine environment and because of their
limitation to surface waters.
Progress: