Traceable sea water temperature measurements performed by optical fibers

This paper describes a technique to perform traceable temperature measurements of the seawater column andseawater surface, based on optical ¿ber Bragg gratings. The paper explains the di¿erent phases of the work done:design of the optical ¿bers, its optical and thermal calibration and onsite measurements of the seawater tem-perature. In the design of these thermometers, special attention was paid to the involved materials in order toprevent any damage of the ¿bers due to the exposure to such rugged environment.The ¿bers were subjected to optical and thermal calibration, with the aim to get traceable measurements andreliable uncertainty calculation of the seawater temperature. The ¿bers were deployed in the Mediterranean Seaand water temperatures were continuously monitored and compared with the most common used thermometerin this environment, CTD, located in the submarine observatory OBSEA.Postprint (author's final draft

Traceable sea temperature measurements performed by optical fibers

In the framework of the EMRP project “ENV 58. Metrology for essential climate variables”, a new technique to perform traceable temperature measurements of the sea water column and sea water surface was designed and it is being studied and applied to a real situation in the submarine observatory (www.obsea.com). This new technique is based on optical fiber Bragg gratings, which implies the distribution of temperature sensors along the fiber. In the design of these distributed thermometers special attention was paid to the involved materials in order to avoid the damages of such corrosive environment. These fibers were calibrated as optical instruments and as thermometers, in order to get traceable measurements, as well as, reliable uncertainty calculation of the seawater temperature profile and of the sea water surface temperature, that are being continuously measured. Besides, these new devices are continuously compared to the current thermometers, CTD, located in the submarine observatoryPostprint (published version

Vertical structure and microphysical observations of winter precipitation in an inner valley during the Cerdanya-2017 field campaign

Precipitation processes at windward and leeward sides of the mountains have been object of study for many decades. Instead, inner mountain valleys, where usually most mountain population lives, have received considerably less attention. This article examines precipitation processes during a winter field campaign in an inner valley of the Pyrenees (NE Spain) using, among other instruments, a K-band vertically pointing Doppler radar (Micro Rain Radar) and a laser-based optical disdrometer (Parsivel). A decoupling is found between the stalled air of the valley and the air of the free atmosphere above the mountain crest level, evidenced by an increase of turbulence and spectral width of precipitation particles. Wind shear layer may promote riming and aggregation of the ice and snow particles. Two main rainfall regimes are found during the campaign: (1) stratiform rainfall mostly produced by water vapour deposition processes, although sometimes riming and aggregation become important, and (2) weak convection with slight dominance of collision-coalescence processes. Precipitation characteristics at the bottom of the valley show typical continental features such as low Liquid Water Content, despite the valley is only about 100 km from the sea. This study demonstrates that inner valley may present distinct precipitation features with respect to windward and leeward precipitation

Optical fiber used as sea water thermometer

Peer ReviewedPostprint (author’s final draft

Underwater seismometer validation

This work verifies and validates the calibration in a marine geophone by means of a hyperbaric chamber before and after the pressure underwater laboratory test. The objective is to characterise the transfer function according to the frequency of coupling between the geophone and the sediment. It is possible to observe the geophone coupling variations through the sediment after the test inside the water pressure at the equivalent of 200 metres depth

Conformity of the quality in the measures

We'll want to implant the awareness of the importance at measurement's quality that must have with systems acquisition own design. The choice of system acquisition will be very important because this system will must fulfill our expectations

Traceable sea temperature measurements performed by optical fibers

In the framework of the EMRP project “ENV 58. Metrology for essential climate variables”, a new technique to perform traceable temperature measurements of the sea water column and sea water surface was designed and it is being studied and applied to a real situation in the submarine observatory (www.obsea.com). This new technique is based on optical fiber Bragg gratings, which implies the distribution of temperature sensors along the fiber. In the design of these distributed thermometers special attention was paid to the involved materials in order to avoid the damages of such corrosive environment. These fibers were calibrated as optical instruments and as thermometers, in order to get traceable measurements, as well as, reliable uncertainty calculation of the seawater temperature profile and of the sea water surface temperature, that are being continuously measured. Besides, these new devices are continuously compared to the current thermometers, CTD, located in the submarine observator

An interoperable architecture for in situ ocean noise monitoring

Special issue 9th MARTECH: International Workshop on Marine Technology: 16-18 June 2021, Vigo, Spain.-- 2 pages, 2 figuresAnthropogenic noise in the oceans has been significantly raising in the past decades due to an increment of human activities, adversely affecting the marine habitat. In order to assess and limit this impact, the long -term monitoring of underwater noise is crucial. Currently, real -time ocean sound data is mainly obtained using cabled observatories, where communications and power are not a constraint. The temporal and spatial coverage of in -situ measurements would be greatly improved if other observation systems such as gliders, moored buoys and profilers could provide real -time ocean sound data. However, these platforms have some intrinsic constraints such as telemetry, computational capacity and power availability. In order to overcome these limitations, an in situ ocean sound monitoring tool is proposed. This tool aims to provide a standardized and homogeneous framework for ocean sound monitoring, compliant with the MSFD directive, capable of interfacing any off -the -shelf hydrophone and deployable from almost any observation platform regardless of its underlying architectureThis work has been supported by the project EMSO-LINK from the European Commission’s Horizon 2020 research and Innovation program under Grant Agreement No. 731036 and partially funded by Generalitat de Catalunya “Sistemas de Adquisición Remota de datos y Tratamiento de la Información en el Medio Marino” (SARTI-MAR)” 2017 SGR 371. Researchers want to acknowledge the support of the Associated Unit Tecnoterra composed by members of Universidad Politécnica de Catalunya (UPC) and the Consejo Superior de Investigaciones Científicas (CSIC)Peer reviewe

Traceable sea temperature vertical profile measured by optical fibers

Measurement of the seawater temperature at different depths to get a vertical temperature profile on the water column is presented in this paper: The acquisition system based on optical fiber Bragg gratings (FBGs) and the subsequent data processed is also presented. The temperature measurements are taken in distributed points along the fiber where the Bragg gratings are located. The paper reports on the robustness of the new technique.Peer Reviewe