The dynamic response of glass rod thermistors

Gregg, Michael C.; Meagher, T.

doi:10.1029/jc085ic05p02779

Cited by 64 publications

(56 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Reynolds number for these probes was order 10 3 . There is evidence that at lower Reynolds numbers (i.e., slower speeds or smaller probes) the time response may vary as w Ϫ1/3 (Gregg and Meagher, 1980) though this has not yet been investigated in this tank. The results suggest that a speed dependent filter could be designed for most CTDs that takes into account the faster response of the thermometer at higher fall rates.…”

Section: F Response Time Variations With Fall Ratementioning

confidence: 99%

“…This is to be expected from the thinning of the fluid boundary layer around the probe with higher velocity (Gregg and Meagher, 1980). We have further explored this dependence using paired temperature sensors on an Idronaut 'Ocean Seven' 319 CTD (Brugherio, Italy).…”

Section: F Response Time Variations With Fall Ratementioning

confidence: 99%

“…In general these instruments have rather slow sample rates, so we focus on estimation of time constants and matching of the temperature and conductivity responses, rather than the frequency response that could be determined for more rapidly sampled microstructure sensors (Lueck et al, 1977;Gregg and Meagher, 1980). Here we discuss results of tests on the Excell CTD developed by FSI for use on profiling floats and include examples with and without the additional thermal contrast provided by the chiller.…”

Section: B An Examplementioning

confidence: 99%

See 2 more Smart Citations

A double-diffusive interface tank for dynamic-response studies

Schmitt¹,

Millard²,

Toole³

et al. 2005

J Mar Res

View full text Add to dashboard Cite

A large tank capable of long-term maintenance of a sharp temperature-salinity interface has been developed and applied to measurements of the dynamical response of oceanographic sensors. A two-layer salt-stratified system is heated from below and cooled from above to provide two convectively mixed layers with a thin double-diffusive interface separating them. A temperature jump exceeding 10°C can be maintained over 1-2 cm (a vertical temperature gradient of order 10 3°C /m) for several weeks. A variable speed-lowering system allows testing of the dynamic response of conductivity and temperature sensors in full-size oceanographic instruments. An acoustic echo sounder and shadowgraph system provide nondisruptive monitoring of the interface and layer microstructure. Tests of several sensor systems show how data from the facility is used to determine sensor response times using several fitting techniques and the speed dependence of thermometer time constants is illustrated. The linearity of the conductivity-temperature relationship across the interface is proposed as a figure of merit for design of lag-correction filters to accurately match temperature and conductivity sensors for the computation of salinity. The effects of finite interface thickness, slow sensor sampling rates and the thermal mass of the conductivity cell are treated. Sensor response characterization is especially important for autonomous instruments where data processing and compression must be performed in-situ, but is also helpful in the development of new sensors and in assuring accurate salinity records from traditional wire-lowered and towed systems.

show abstract

Section: F Response Time Variations With Fall Ratementioning

confidence: 99%

Section: F Response Time Variations With Fall Ratementioning

confidence: 99%

Section: B An Examplementioning

confidence: 99%

See 1 more Smart Citation

A double-diffusive interface tank for dynamic-response studies

Schmitt¹,

Millard²,

Toole³

et al. 2005

J Mar Res

View full text Add to dashboard Cite

show abstract

“…This segment setting is similar to that used by HMT16. After FFT, temperature gradient spectra were amplified by a double-pole low-pass filter function (Gregg and Meagher 1980) with a time constant t 5 3 ms following GYN16: f1 1 (2pf t) 2 g 2 , where f is frequency. The « estimated from thermistors by applying this form of correction to temperature spectra was confirmed to be comparable with « from the shear probes within a factor of 3 in the range of 10 210 , « , 3 3 10 27 W kg 21 (GYN16).…”

Section: B Analysis Methods Of Turbulence Intensitymentioning

confidence: 99%

“…As the time constant of the thermistors (;7 s; ms, for half attenuation) is insufficient for resolving relatively strong turbulence, various correction procedures have been proposed (Lueck et al 1977;Gregg and Meagher 1980). In our previous companion study (Goto et al 2016, hereafter GYN16), a double-pole (DP) low-pass filter method of correction, as proposed by Gregg and Meagher (1980), with a quarter attenuation time constant of 3 ms was demonstrated to be the most appropriate for a wide range of turbulent energy dissipation rates « (10 210 , « , 3 3 10 27 W kg…”

Section: Introductionmentioning

confidence: 99%

Comparison of Turbulence Intensity from CTD-Attached and Free-Fall Microstructure Profilers

Goto

Yasuda

Nagasawa

2018

Journal of Atmospheric and Oceanic Technology

View full text Add to dashboard Cite

Turbulence intensity estimated from fast-response thermistors is compared between conductivitytemperature-depth (CTD)-attached and free-fall microstructure profilers, conducted at the same location within 2 h. The agreement is generally good but anomalously overestimated values, deviating from a lognormal distribution, appear sporadically in the CTD-attached method. These overestimated outliers are evident as spiky patches in the raw temperature gradient profiles.

show abstract

Observational validation of the diffusive convection flux laws in the Amundsen Basin, Arctic Ocean

2015

View full text Add to dashboard Cite

The low levels of mechanically driven mixing in many regions of the Arctic Ocean make double diffusive convection virtually the only mechanism for moving heat up from the core of Atlantic Water towards the surface. In an attempt to quantify double diffusive heat fluxes in the Arctic Ocean, a temperature microstructure experiment was performed as a part of the North Pole Environmental Observatory (NPEO) 2013 field season from the drifting ice station Barneo located in the Amundsen Basin near the Lomonosov Ridge (89.5°N, 75°W). A diffusive convective thermohaline staircase was present between 150 and 250 m in nearly all of the profiles. Typical vertical heat fluxes across the high‐gradient interfaces were consistently small, O(10−1) W m−2. Our experiment was designed to resolve the staircase and differed from earlier Arctic studies that utilized inadequate instrumentation or sampling. Our measured fluxes from temperature microstructure agree well with the laboratory derived flux laws compared to previous studies, which could find agreement only to within a factor of two to four. Correlations between measured and parameterized heat fluxes are slightly higher when using the more recent Flanagan et al. [2013] laboratory derivation than the more commonly used derivation presented in Kelley [1990]. Nusselt versus Rayleigh number scaling reveals the convective exponent, η, to be closer to 0.29 as predicted by recent numerical simulations of single‐component convection rather than the canonical 1/3 assumed for double diffusion. However, the exponent appears to be sensitive to how convective layer height is defined.

show abstract

The dynamic response of glass rod thermistors

Cited by 64 publications

References 6 publications

A double-diffusive interface tank for dynamic-response studies

A double-diffusive interface tank for dynamic-response studies

Comparison of Turbulence Intensity from CTD-Attached and Free-Fall Microstructure Profilers

Observational validation of the diffusive convection flux laws in the Amundsen Basin, Arctic Ocean

Contact Info

Product

Resources

About