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MArine RAdiometric Spectrometer: system deployment and application development programme

Objective


The marine radiometric spectrometer system MARAS has been developed to perform spectral radiometry in the ocean. By simultaneous collection of upwelling and downwelling scalar and vector spectral irradiance the apparent optical properties of a water body can be estimated. The multicollector system has collectors mounted at 2 depths so that it is relatively impervious to changes in the ambient light levels and only requires relative, rather than absolute, calibration of its sensor sensitivities.

The measurements of apparent optical properties are used in an inversion system which has been developed and tested by simulated radiative transfer models and can be shown to yield useful estimates of the inherent absorption and scattering properties of the ocean. The direct effect of ocean constituents on both the measurements themselves, and on the derived apparent and inherent optical properties are demonstrated.
The Marine Radiometric Spectrometer (MARAS) system is designed to characterise the optical properties of the marine environment. The system will enable scientists to study the effects of different marine constituents on these optical properties. Global monitoring of Earth's marine surface by future remote sensing ocean colour satellite systems will require a much better understanding of these optical properties, and also of the way in which these optical properties affect the spectral shape of Top of the Atmosphere (TOA) radiation.

After completion of the transmissiometer/scatterometer, the technical and scientific evaluation of the instrument will be performed in a series of test cruises designed to evaluate the system performance in open and coastal waters. The optimum approach to the use of spectral radiometer data has to be developed. Instrument calibration, the extraction of constituent estimates, the estimation of inherent optical properties, and the modelling of the radiative transfer process to produce TOA radiance estimates, are all elements of this validation programme. This programme will aim to establish the norms to be used in the exchange of optical data for ocean colour science and subsequently for the validation and vicarious calibration of future global monitoring satellite systems.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITY COLLEGE DUBLIN
Address
Stillorgan Road
4 Dublin
Ireland

Participants (6)

Athens Technology Center SA
Greece
Address
16,Kanari Street 16
14562 Athens
Computer Applied Techniques Ltd.
Ireland
Address
3,Saint James' Terrace
26 Dublin
ENVIRONMENTAL PROTECTION AGENCY
Ireland
Address
Johnstown Castle
4 Wexford
FREIE UNIVERSITAET BERLIN
Germany
Address
Malteserstrasse 74-100
12249 Berlin
GKSS - FORSCHUNGSZENTRUM GEESTHACHT GMBH
Germany
Address
Max-planck-strasse 1
Geesthacht
Leeds Metropolitan University
United Kingdom
Address
Calverley Street
LS1 3HE Leeds