Experimental research on continuous measurement of all fiber optic ocean temperature-depth profile

AbstractDuring the 1973-74 Antarctic field season, two electrical resistivity profiles were completed along directions perpendicular to each other at a site in the south-easternpart of the Ross Ice Shelf. These profiles differ from each other only at short electrode spacings (less than 10 m) indicating no measurable horizontal anisotropy below the uppermost firn zone. The shape of the apparent resistivity curves is similar to that found by Hochstein on the Ross Ice Shelf near Roosevelt Island, but is displaced toward lower resistivities despite the colder 10 m temperature (—29°C instead of —26°C) at the more southerly site. Some factor other than temperature must therefore be effective in determining the overall magnitude of the resistivities in the shelf, although the variation with depth can still be expected to be primarily a temperature phenomenon.A computer program has been written to calculate apparent resistivities based on Crary’s analysis of temperatures in an ice shelf. Results are not yet available; when completed they should indicate the sensitivity of the resistivity measurements to differences in the temperature- depth profile, and hence their usefulness in estimating bottom melt/freeze rates.

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Dual-Analyte Fiber-Optic Sensor for the Simultaneous and Continuous Measurement of Glucose and Oxygen

Analytical Chemistry ◽

10.1021/ac00116a021 ◽

1995 ◽

Vol 67 (20) ◽

pp. 3746-3752 ◽

Cited By ~ 80

Author(s):

Lin. Li ◽

David R. Walt

Keyword(s):

Fiber Optic ◽

Continuous Measurement ◽

Fiber Optic Sensor ◽

Optic Sensor

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Deep Ocean Temperature Measurement with an Uncertainty of 0.7 mK

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-15-0013.1 ◽

2015 ◽

Vol 32 (11) ◽

pp. 2199-2210 ◽

Cited By ~ 10

Author(s):

Hiroshi Uchida ◽

Toshiya Nakano ◽

Jun Tamba ◽

Januarius V. Widiatmo ◽

Kazuaki Yamazawa ◽

...

Keyword(s):

Temperature Measurement ◽

Deep Ocean ◽

National Standard ◽

Attitude Motion ◽

National Metrology Institute ◽

Ocean Temperature ◽

Triple Point Of Water ◽

Salinity Data ◽

Temperature Depth ◽

Gallium Melting Point

AbstractThe uncertainty of deep ocean temperature (~1°C) measurement was evaluated. The time drifts of six deep ocean standards thermometers were examined based on laboratory calibrations as performed by the manufacturer in triple point of water (TPW) cells and gallium-melting-point (GaMP) cells. The time drifts ranged from −0.11 to 0.14 mK yr−1. Three of the six thermometers were evaluated at the National Metrology Institute of Japan in five TPW cells and a GaMP cell, and the temperature readings agreed with the realized temperature of the national standard cells of Japan within ±0.14 and ±0.41 mK for TPW and GaMP, respectively. The pressure sensitivities of the deep ocean standards thermometers were estimated by comparison with conductivity–temperature–depth (CTD) thermometers in the deep ocean, and no notable difference was detected. Pressure sensitivities of the two CTD thermometers were examined by laboratory tests, and the results suggest that the deep ocean standards thermometers have no pressure sensitivity, at least up to 65 MPa. The position and attitude motion of the CTD system can affect temperature and salinity data quality. The overall expanded uncertainty of the deep ocean temperature measurement (up to 65 MPa) by the CTD thermometer calibrated in reference to the deep ocean standards thermometer is estimated to be 0.7 mK.

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Variations in air and ground temperature and the POM-SAT model: results from the Northern Hemisphere

Climate of the Past ◽

10.5194/cp-3-611-2007 ◽

2007 ◽

Vol 3 (4) ◽

pp. 611-621 ◽

Cited By ~ 16

Author(s):

R. N. Harris

Keyword(s):

Time Series ◽

Northern Hemisphere ◽

Depth Profile ◽

Temperature Profiles ◽

Thermal Transients ◽

Ground Temperatures ◽

Climate Reconstructions ◽

Forcing Function ◽

Borehole Temperatures ◽

Temperature Depth

Abstract. The POM-SAT model for comparing air and ground temperatures is based on the supposition that surface air temperature (SAT) records provide a good prediction of thermal transients in the shallow subsurface of the Earth. This model consists of two components, the forcing function and an initial condition, termed the pre-observational mean (POM). I explore the sensitivity of this model as a function of forcing periods at time scales appropriate for climate reconstructions. Synthetic models are designed to replicate comparisons between borehole temperatures contained in the global database of temperature profiles for climate reconstructions and gridded SAT data. I find that the root mean square (RMS) misfit between forcing functions and transient temperature profiles in the subsurface are sensitive to periods longer than about 50 years, are a maximum when the period and the 150-year time series are equal and then decreases for longer periods. The magnitude of the POM is a robust parameter for periods equal to or shorter than the length of this time series. At longer periods there is a tradeoff between the amplitude of the forcing function and the POM. These tests provide guidelines for assessing comparisons between air and ground temperatures at periods appropriate for climate reconstructions. The sensitivity of comparisons between the average Northern Hemisphere gridded SAT record and subsurface temperature-depth profile as a function of forcing period is assessed. This analysis indicates that the Northern Hemisphere extratropical average SAT and reduced temperature-depth profile are in good agreement. By adding modest heat to the subsurface at intermediate periods some improvement in misfit can be made, but this extra heat has negligible influence on the POM. The joint analysis of borehole temperatures and SAT records indicate warming of about 1.1°C over the last 500 years, consistent with previous studies.

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Temperature investigation and modeling on the Filchner-Ronne Ice Shelf, Antarctica

Annals of Glaciology ◽

10.3189/1994aog20-1-377-385 ◽

1994 ◽

Vol 20 ◽

pp. 377-385 ◽

Cited By ~ 1

Author(s):

K. Grosfeld ◽

F. Thyssen

Keyword(s):

Depth Profile ◽

Basal Layer ◽

Melting Rate ◽

Ice Shelf ◽

Depth Profiles ◽

Steady State Temperature ◽

Antarctic Expedition ◽

Field Season ◽

Basal Melting ◽

Temperature Depth

During the German Antarctic Expedition field season 1989–90. hotwater drilling was undertaken on the Filchner-Ronne Ice Shelf (FRIS) at 77° S 52°c W to investigate the temperature-depth profile and the bottom-melting rate, which arc significant parameters for mass- and energy-balance studies of the ice shelf. Remeasurements of installed chains in 1991-92 yie1ded reliable results.Taking glaciological, geodetic and geophysical data on a flowline through the central part of FRIS. we developed a two-dimensional thermal model to reconstruct the measurernents from a steady-state temperature depth profile about 550 km upstream on Möllereisstrom. Considering mass and energy conservation, a basal layer of 350 m of marine ice was calculated with thermal properties, depending on salinity and temperature. In areas with strong basal freezing, almost isothermal depth profiles in the marine ice layer are derived. Further downstream, in areas of basal melting, a nearly cubic temperarure-depth profile is observed.

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