Περίληψη:
The societal benefits of satellite ocean colour include aiding the
management of the marine ecosystem, helping understand the role of the
ocean ecosystem in climate change, aquaculture, fisheries, coastal zone
water quality, and the mapping and monitoring of harmful algal blooms.
Ocean colour is also designated as an essential climate variable by the
Global Climate Observing System (GCOS). However, in order to have
confidence in earth observation data, measurements made at the surface
of the Earth, with the intention of providing verification or validation
of satellite mounted sensor measurements, should be trustworthy and of
the same high quality as those taken with the satellite sensors
themselves. In order to be trustworthy, in situ validation measurements
should include an unbroken chain of SI traceable calibrations and
comparisons and full uncertainty budgets for each of the in situ sensors
used. This metrological traceability is beginning to be demanded by the
space agencies for satellite validation measurements and, for ocean
colour, should follow the guidelines and protocols of the ESA Fiducial
Reference Measurements for Satellite Ocean Colour (FRM4SOC) project
(www.frm4soc.org). Until now, this has not been the case for most
measurements used for validation, including those taken in the Aegean
and Eastern Mediterranean. Subsequently, the Hellenic Centre for Marine
Research (HCMR), in cooperation with the Laboratory of Optical Metrology
(LOM), has started to follow the FRM direction by ensuring that the
radiometers of its optical suite underwent SI- traceable absolute
radiometric calibration. This included an estimate of the radiometry
calibration uncertainty budget and was performed at the marine optical
laboratory of the European Commission's Joint Research Centre prior to
their deployment on the recent PERLE- 2 oceanographic cruise in the
Eastern Mediterranean (Feb- Mar 2019). As well as irradiance and
radiance sensors, the HCMR optical suite also houses instruments for
measuring inherent optical properties (IOP) of the water column.
Therefore, this paper presents the in-water radiometry matchups from
PERLE-2 with Sentinel-3 Ocean and Land Colour Instrument (OLCI)
measurements, and investigates their validation potential. It also
presents the PERLE-2 cruise profile chlorophyll and backscatter
measurements that aid this effort through characterizing the light
scattering and absorbing constituents that contribute to the signal
detected by satellite ocean colour sensors during validation matchups.
Συγγραφείς:
Banks, A. C.
Drakopoulos, P. G.
Chaikalis, S.
Spyridakis, N.
and Karageorgis, A. P.
Psarra, S.
Taillandier, V
D'Ortenzio,
F.
Sofianos, S.
de Madron, Xavier Durrieu
