scholarly journals Deep Ocean Temperature Measurement with an Uncertainty of 0.7 mK

2015 ◽  
Vol 32 (11) ◽  
pp. 2199-2210 ◽  
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.

In Situ Calibration of Moored CTDs Used for Monitoring Abyssal Water

2008 ◽  
Vol 25 (9) ◽  
pp. 1695-1702 ◽  
Author(s):  
Hiroshi Uchida ◽  
Takeshi Kawano ◽  
Masao Fukasawa
Keyword(s):  
Potential Temperature ◽  
Pressure Sensors ◽  
Heat Content ◽  
Deep Ocean ◽  
Volume Transport ◽  
In Situ Calibration ◽  
Before And After ◽  
Salinity Data ◽  
Temperature Depth

Abstract To monitor changes in heat content and geostrophic volume transport of abyssal water accurately, 50 moored conductivity–temperature–depth (CTD) recorders used for density measurements were calibrated in situ by simultaneous observations with accurate shipboard CTDs. Comparisons of the data from the moored and shipboard CTDs showed pressure sensitivities of 0–3 mK at 6000 dbar for the temperature sensors of the moored CTDs. From the in situ calibrations, the uncertainties of the moored CTD data for the deep ocean (≥3000 dbar) were estimated to be 0.6 dbar, 0.6 mK, and 0.0026 for pressure, temperature, and salinity, respectively, relative to the shipboard CTD reference. Time drifts of the moored CTD data, estimated from the in situ calibrations before and after 17- or 14-month mooring deployments in the deep ocean, were considerably smaller than typical stabilities as specified by the manufacturer. However, time drifts of the pressure sensors tended to be negative and the result suggests that pressure data from most present Argo floats, which use the same type of pressure sensor, may have a systematic negative bias. Time series salinity data calculated from the in situ–calibrated CTDs were slightly biased (mean of +0.0014) with respect to the shipboard CTD salinity data, based on potential temperature–salinity relationships, possibly due to a disequilibrium of the moored CTD conductivity sensors during the in situ calibrations.

First measurement service applied to event dating for reliable business transactions: metrology for digital transformation using Colombian legal time.

2021 ◽  
Author(s):  
Claudia Fernanda Rodriguez ◽  
Keyword(s):  
Digital Transformation ◽  
National Standards ◽  
National Standard ◽  
National Metrology Institute ◽  
Remote Measurement ◽  
Time Service ◽  
Network Time ◽  
Network Time Protocol ◽  
National Comparison ◽  
The Difference

Diffusing the legal time in Colombia is one missional assessment of INM (National Metrology Institute of Colombia). This is done via a public IP through an NTP server (Network Time Protocol Server) disciplined to the National Standard of Time and Frequency. So, the companies can synchronize their servers, but they do not have certainty about the difference that exists between the time of the client-server and the legal time of the INM server because there is not a constant verification implemented by themselves. In Colombia, the demand for the legal time service has increased because it is used by many companies due to the rise of innovative applications such as time-stamp, digital signature, electronic invoice, and economic transactions. This has an impact on the economic environment of a country for world trade. For this reason, the INM of Colombia implemented a new service to measure the synchronization offset with the legal time, which allows the companies to have a new service that generates reliability respecting the time they use to provide their services. Inspired by the INM contribution to the international comparison Universal Time Coordinated (UTC) and the intercomparison of the National Standards of Time and Frequency implemented through the SIM time scale (SIMT) using GPS (Global Positioning System), the INM developed a customized application for national comparison using NTP. As a result, this is the first remote measurement service as evidence of metrology for digital transformation in Colombia in the field of time and frequency.

An Optical Fiber Farby-Perot Temperature Sensor for Rapid Ocean Temperature Measurement

2018 ◽  
Vol 45 (12) ◽  
pp. 1210001
Author(s):  
孟华 Meng Hua ◽  
李海洋 Li Haiyang ◽  
曹占启 Cao Zhanqi
Keyword(s):  
Optical Fiber ◽  
Temperature Measurement ◽  
Temperature Sensor ◽  
Ocean Temperature

scholarly journals Development of Shallow-Depth Soil Temperature Estimation Model Based on Thermal Response in Permafrost Area

2018 ◽  
Vol 8 (10) ◽  
pp. 1886 ◽  
Author(s):  
Keunbo Park ◽  
Heekwon Yang ◽  
Bang Lee ◽  
Dongwook Kim
Keyword(s):  
Soil Temperature ◽  
Temperature Measurement ◽  
Thermal Response ◽  
Estimation Model ◽  
Temperature Estimation ◽  
Soil Temperatures ◽  
Different Depths ◽  
The Relationship ◽  
Temperature Depth ◽  
Good Agreement

A soil temperature estimation model for increasing depth in a permafrost area in Alaska near the Bering Sea is proposed based on a thermal response concept. Thermal response is a measure of the internal physical heat transfer of soil due to transferred heat into the soil. Soil temperature data at different depths from late spring to the early autumn period at multiple permafrost sites were collected using automatic sensor measurements. From the analysis results, a model was established based on the relationship between the normalized cumulative soil temperatures (CRCST*i,m and CST*ud,m) of two different depths. CST*ud,m is the parameter of the soil temperature measurement at a depth of 5 cm, and CRCST*i,m is the parameter of the soil temperature measured at deeper depths of i cm (i = 10, 15, 20, and 30). Additionally, the fitting parameters of the mathematical models of the CRCST*i,m–CST*ud,m relationship were determined. The measured soil temperature depth profiles at a different site were compared with their predicted soil temperatures using the developed model for the model validation purpose. Consequently, the predicted soil temperatures at different soil depths using the soil temperature measurement of the uppermost depth (5 cm) were in good agreement with the measured results.

Calibration Tests of New Type Flow-Metering System by Ultrasonic Pulse-Doppler Profile-Velocimetry at National Standard Loops

2006 ◽  
Author(s):  
Michitsugu Mori ◽  
Kenichi Tezuka ◽  
Takeshi Suzuki ◽  
Mark Sapia ◽  
Edward Schrull ◽  
...  
Keyword(s):  
Ultrasonic Pulse ◽  
High Accuracy ◽  
National Standard ◽  
National Metrology Institute ◽  
Expanded Uncertainty ◽  
Flow Metering ◽  
Doppler Profile ◽  
Type Flow ◽  
New Type ◽  
Pulse Doppler

To verify high accuracy of a new type flow-metering system based on the measurements of line velocity profiles, eliminating Profile Factors, calibration tests of “UDF”, the flow-metering system by ultrasonic pulse-Doppler profile-velocimetry, were conducted at national standard loops worldwide, including the National Institute of Standard Technology (NIST) of the U.S. Department of Commerce, the National Metrology Institute of Japan (NMIJ) of the National Institute of Advanced Industrial Science and Technology (AIST) in Japan, the Nederlands Meetinstituut (NMI) in Netherlands, and the Centro National de Metrologia (CENAM) in Mexico. The deviations of UDF to the standard loops in the calibration tests for water were found between −0.23% and +0.26% at NIST, 0.1% and 0.4% at NMIJ, and −0.52% and +0.59% at NMI in terms of the average values of each measurement. Following improvements to the UDF System, the calibration tests at CENAM exhibited the deviations between −0.18% and +0.23% and the expanded uncertainty with ±0.21%.

scholarly journals Model‐Derived Uncertainties in Deep Ocean Temperature Trends Between 1990 and 2010

2019 ◽  
Vol 124 (2) ◽  
pp. 1155-1169 ◽  
Author(s):  
F. K. Garry ◽  
E. L. McDonagh ◽  
A. T. Blaker ◽  
C. D. Roberts ◽  
D. G. Desbruyères ◽  
...  
Keyword(s):  
Deep Ocean ◽  
Ocean Temperature ◽  
Temperature Trends

Shallow sediment temperature perturbations and sediment thermal conductivities, Canadian Beaufort Shelf

1987 ◽  
Vol 24 (11) ◽  
pp. 2223-2234 ◽  
Author(s):  
Alan E. Taylor ◽  
Vic Allen
Keyword(s):  
Thermal Effects ◽  
Seasonal Changes ◽  
Sediment Cores ◽  
Deep Ocean ◽  
Regional Survey ◽  
Bottom Water Temperature ◽  
Depth Profiles ◽  
Wide Range ◽  
Temperature Depth ◽  
Thermal Conductivities

A regional survey of sediment temperatures and thermal conductivities was conducted at 33 stations across the outer shelf of the Canadian Beaufort Sea. Techniques developed for deep-ocean heat-flow investigations were used to study the upper 3 m of sediments. Temperature–depth profiles exhibit curvatures that may be explained by seasonal changes in bottom-water temperature; some curvatures may arise from other causes. It is unlikely that thermal effects of the underlying, degradational permafrost can be detected from such shallow temperatures because of the magnitude of, and lack of independent knowledge of, these transient and local influences. Thermal conductivities measured on sediment cores and corrected to −1 °C range from 0.9 to 2.4 W m−1 K−1 (average 1.26 ± 0.2 W m−1 K−1). These values are higher than typical conductivities of deep-ocean sediments. The wide range of thermal conductivities observed across the outer Beaufort Shelf may be explained by the presence of a varying fraction of quartz sand that represents a component of high conductivity.

Drift Characteristics of a Moored Conductivity–Temperature–Depth Sensor and Correction of Salinity Data

2005 ◽  
Vol 22 (3) ◽  
pp. 282-291 ◽  
Author(s):  
Kentaro Ando ◽  
Takeo Matsumoto ◽  
Tetsuya Nagahama ◽  
Iwao Ueki ◽  
Yasushi Takatsuki ◽  
...  
Keyword(s):  
Linear Trend ◽  
Drift Time ◽  
Calibration Data ◽  
Depth Sensor ◽  
Salinity Data ◽  
Corrected Data ◽  
Western Portion ◽  
Triton Buoy ◽  
Temperature Depth

Abstract The temperature and conductivity drift (time change of the characteristics) of moored SBE37IM conductivity and temperature (CT) sensors was investigated by pre- and postdeployment calibration of the Triangle TransOcean Buoy Network (TRITON). This buoy network comprises the western portion of the basinwide (Tropical Atmosphere Ocean) TAO/TRITON buoy array, which monitors phenomena such as El Niño and contributes to forecasting climate change. Over the time of deployment the drift of the temperature sensors was very small, within 3 mK of the postdeployment calibration data. The drift of the conductivity sensors was more significant. After 1 yr of mooring, conductivity drift observed in the shallowest layer (1.5–100 m) was positive and 0.010 S m−1 [equivalent to 0.065 (PSS-78) at 30°C and 6 S m−1; here, 1 S is 1 Ω−1] at 6 S m −1 on average. Drift observed in the thermocline layer (125–200 m) was also positive and 0.0053 S m−1 [0.034 (PSS-78)] at 6 S m−1 on average. Conversely, the drift of conductivity in the deepest layer (250–750 m) was 0.00002 S m−1 with a standard deviation of 0.001 S m−1 [0.0065 (PSS-78)]. Assuming a linear trend of conductivity drift with time, the authors attempted to correct the conductivity data using the postdeployment calibration data. The corrected data for about 80% of the sensors exhibited smaller differences than the uncorrected data when compared with the in situ conductivity–temperature–depth (CTD) data. However, the corrected salinity data became worse than the uncorrected data for about 20% of the sensors. The reasons for these errors are also discussed in this paper.

scholarly journals Employing Satellite-Derived Sea Ice Concentration to Constrain Upper-Ocean Temperature in a Global Ocean GCM

2008 ◽  
Vol 21 (17) ◽  
pp. 4498-4513 ◽  
Author(s):  
Achim Stössel
Keyword(s):  
Sea Ice ◽  
Deep Ocean ◽  
Global Ocean ◽  
Upper Ocean ◽  
Ocean Temperature ◽  
Freshwater Input ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
Ocean Properties

Abstract The quality of Southern Ocean sea ice simulations in a global ocean general circulation model (GCM) depends decisively on the simulated upper-ocean temperature. This is confirmed by assimilating satellite-derived sea ice concentration to constrain the upper-layer temperature of a sea ice–ocean GCM. The resolution of the model’s sea ice component is about 22 km and thus comparable to the pixel resolution of the satellite data. The ocean component is coarse resolution to afford long-term integrations for investigations of the deep-ocean equilibrium response. Besides improving the sea ice simulation considerably, the simulations with constrained upper-ocean temperature yield much more realistic global deep-ocean properties, in particular when combined with glacial freshwater input. Both outcomes are relatively insensitive to the passive-microwave algorithm used to retrieve the ice concentration being assimilated. The sensitivity of the long-term global deep-ocean properties and circulation to the possible freshwater input from ice shelves and to the parameterization of vertical mixing in the Southern Ocean is reevaluated under the new constraint.

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