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Introduction
Knowledge
of phytoplankton dynamics and distributions in North Sea coastal
waters is vital to ensure a scientific basis for coherent management
of the coastal environment and the human activities which impact
on or benefit from it. On the one hand phytoplankton abundance
and species composition are influenced by anthropogenic nutrient
supply from agricultural and industrial sources. On the other
hand, human activities such as fisheries and mariculture may be
affected by phytoplankton, which constitute the base of the marine
food chain. Furthermore, phytoplankton plays a major role in the
marine foodweb through the flow and cycling of carbon and other
materials to higher trophic levels that helps to maintain high
marine biodiversity. The common environmental policies, of both
the European Union and the Oslo-Paris Convention (OSPAR) are underpinned
by the role of phytoplankton biomass and its impact on sustainable
development. Monitoring of phytoplankton, which is currently carried
out by all North Sea states, is conventionally based on timely
and costly water sampling programs. This results in sparse spatial
and temporal coverage and gives only a vague impression of the
dynamics of phytoplankton in relation to human activities. Satellite
remote sensing of chlorophyll concentrations therefore offers
a significant and powerful tool supplementing conventional sampling
surveys by providing synoptic observations of the entire coastal
zone. Remote sensing algorithms for the accurate retrieval of
chlorophyll in turbid coastal waters are still under development.
The spatial, spectral and radiometric resolution of existing satellite
sensors (e.g. SeaWiFS) is insufficient for chlorophyll detection
in coastal waters where there is strong absorption and backscatter
by non-phytoplanktonic matter. The new generation satellite sensor
MERIS aboard ENVISAT launched by the European Space Agency, which
is specifically designed for high resolution optical detection
in turbid Case II waters incorporating programmable band widths
and positions, could potentially revolutionize the monitoring
of algal biomass in coastal zones. Before this can be achieved
MERIS algorithms require rigorous development, testing and validation.
 Primary objectives
The
primary objectives (from a user/operationalisation point of view)
are:
- To
support the monitoring of the eutrophication status of the North
Sea and the effects of nutrient reduction by measuring and validating
a key bio-geo-physical parameter (Chlorophyll concentration)
using ENVISAT/MERIS satellite observations.
- To
establish, strengthen and build on the European potential in
Earth observation (EO) technologies that will be used to monitor,
understand and protect the environment of the North Sea and
related coastal waters. This will be achieved through co-operation
between remote sensing institutes on all borders of the North
Sea, private companies and end users.
The
primary objectives (from a research point of view) of the REVAMP
project are:
- To
develop an improved validated product from the secured European
mission ENVISAT, namely validated regional chlorophyll concentrations
for case-II waters (North Sea)
- To
extend scientific understanding of the nature of the MERIS observed
signals beyond empirical relationships by applying state-of-the
art analytical inversions of bio-optical models (Neural networks,
Matrix inversion techniques)
- To
parameterise bio-optical models to a high quality, innovative
in-situ and laboratory techniques are required. This will include
only the measurements of regional variations in both absorption
and backscattering due to phytoplankton and other water components.
Backscattering remains poorly understood .
- To
develop reliable information sources for North Sea policy building,
in the form of yearly atlases (from spring 2002 - spring 2003)
which will contain validated CHL concentration maps for the
North Sea and indices to underlying processes such as a eutrophication
index and other value added products such as annual peak concentration
etc.
- To
extend MERIS validation beyond the ESA validation phase and
to study and recommend further strategies for low cost, continuous
and long term validation
Secondary
objectives
To
fulfil these primary objectives, REVAMP will address the following
secondary objectives in corresponding work packages:
- To
collect and analyse historical North Sea data on concentrations
and optical properties of optical active constituents of the
North Sea. To integrate selected, complete and validated data
into one database, which will be distributed within the consortium.
To complement this database with historical satellite observations
and products ( e.g. SeaWiFS) in order to determine regions in
the North Sea with recurrent phytoplankton blooms and homogeneous
phytoplankton signatures
- To
use the historical database, together with data collected in
2002/2003, to select parameterise, calibrate and validate bio-optical
models and inversion algorithms that are suitable for regional
CHL concentration retrieval from MERIS observations. The final
algorithm and regional parameter sets will be documented into
the Regional Algorithm Theoretical Base Document (RATBD).
- To
collect a limited, complementary (spring 2002 to spring 2003)
field data-set of high quality observations to further calibrate
bio-optical models and inversion algorithms (2002 data), but
especially to validate regional CHL products derived from MERIS
observations (2002 and spring 2003 data). Field surveys will
be dedicated to the collection of high quality standard observations
of inherent and apparent optical properties and concentrations
of key optical variables. The project will also use innovative
techniques for the measurement of water leaving radiance and
scattering. As a secondary goal, additional data will be collected
to validate MERIS atmospheric correction and the standard water
leaving radiance product, in order to understand errors in the
final regional CHL-products due to incomplete or erroneous atmospheric
correction. Although REVAMP is not dedicated to adjusting MERIS
atmospheric correction, two of the partners have expertise in
this field and will co-operate closely with ESA to advise on
improvements.
- To
build a MERIS Regional CHL-Products Processor (MEP) based on
existing building blocks; the initial work will consist of compiling
the user requirements, and specifically the translation of the
RATBD into processing and product requirements. Following the
development and implementation phase, the processor software
will be validated using MERIS measurements and in-situ data.
Preceding the actual processing, requirements for image suitability
and indicators (flags) for CHL-product quality will be developed
and incorporated into MEP. The products will not only include
CHL but also a data quality assessment.
- To
develop relevant Value Added Products. To produce a prototype
CHL atlas (including prototype Value Added Products) and to
liaise with intermediate user consultants to fine-tune the products
to user requirements.
- To
make the final 2002/2003 ATLAS of CHL and Value Added Products
maps, to print and disseminate the atlas and to conduct a final
workshop to demonstrate the product and to define future versions
in collaboration with the end user.
Tertiary
objectives
REVAMP
has the following tertiary objectives:
- To
organise a series of workshops with partners and interested
end users to discuss project progress and to integrate various
approaches to CHL-monitoring
- To
participate in regular ESA-consultations to report on MERIS
validation
-
To produce a number of high standard scientific publications
in relevant journals and presentations at European and International
Conferences, including contributions to conference proceedings
-
To actively use the Internet for data dissemination using a
password protected website for partners and a publicly accessible
website for the dissemination of results
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