Government Policy in Support of Domestic Agriculture: Costs and Benefits, The European Community

Agricultural and Food Policy,

Aerospatial remote sensing as catalyst of an operational marine fishery (halieutic) science

A brief balance of the attainments and limits in the modern halieutic (fishery biology and economy) field is stricken and shows off the gap between the present management structure and the present problems. The surface tuna fishery case is thoroughly studied, considering its specificity and its economical importance. From there, it appears that conclusive strides will be made by halieutic science through the knowledge of the relationship between tuna and its environment. Some tuna environment studies are presented through typical remote sensing examples and introduce the basis of a coherent theory of tuna behaviour which can be schematically summarized by this basic general hypothesis; namely, that if tuna are present in a zone they will be inclined to aggregate close to any anomalies (gradients) of parameters in their environmental sensing field. From there several models are presented in order to assess or forecast surface tuna stock

Static spectropolarimeter concept adapted to space conditions and wide spectrum constraints

The issues related to moving elements in space and instruments working in broader wavelength ranges lead to a need for robust polarimeters, efficient on a wide spectral domain, and adapted to space conditions. As part of the UVMag consortium, created to develop spectropolarimetric UV facilities in space, such as the Arago mission project, we present an innovative concept of static spectropolarimetry. We studied a static and polychromatic method for spectropolarimetry, applicable to stellar physics. Instead of modulating the polarization information temporally, as usually done in spectropolarimeters, the modulation is performed in a spatial direction, orthogonal to the spectral one. Thanks to the proportionality between phase retardance imposed by a birefringent material and its thickness, birefringent wedges can be used to create this spatial modulation. The light is then spectrally cross-dispersed, and a full-Stokes determination of the polarization over the whole spectrum can be obtained with a single-shot measurement. The use of Magnesium Fluoride wedges, for example, could lead to a compact, static polarimeter working at wavelengths from 0.115 mm up to 7 mm. We present the theory and simulations of this concept, as well as laboratory validation and a practical application to Arago.Comment: Article accepted for publication in Applied Optics on 20 July 201