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

Goto, Yasuyuki; Yasuda, Ichiro; Nagasawa, Mitsuru

doi:10.1175/jtech-d-17-0069.1

Cited by 21 publications

(33 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The K ρ was also measured by using CTD-attached fast-response thermistors (AFPO7; Rockland Scientific International Company) (50, 51) on the KH-17-3 cruise for open water in the subarctic Pacific (SI Appendix, Table S2). Comparison study between these two measurement methods have been conducted at 100 stations in several cruises (51), including KH-09-4 (SI Appendix, Table S2) (51). Turbulence intensity estimated from CTD-fast-response thermistors was compared to those by free-fall microstructure profilers, conducted at the same location within 2 h, and the result was reported in Goto et al (51), where « is valid for 10 −10 < « <10 −8 W/kg after response correction (50) and data screening (51), and it has been confirmed that « from both measurement methods are comparable and within a factor of 3 (51).…”

Section: Methodsmentioning

confidence: 99%

Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation

Nishioka

Obata

Ogawa

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The mechanism by which nutrients in the deep ocean are uplifted to maintain nutrient-rich surface waters in the subarctic Pacific has not been properly described. The iron (Fe) supply processes that control biological production in the nutrient-rich waters are also still under debate. Here, we report the processes that determine the chemical properties of intermediate water and the uplift of Fe and nutrients to the main thermocline, which eventually maintains surface biological productivity. Extremely nutrient-rich water is pooled in intermediate water (26.8 to 27.6 σθ) in the western subarctic area, especially in the Bering Sea basin. Increases of two to four orders in the upward turbulent fluxes of nutrients were observed around the marginal sea island chains, indicating that nutrients are uplifted to the surface and are returned to the subarctic intermediate nutrient pool as sinking particles through the biological production and microbial degradation of organic substances. This nutrient circulation coupled with the dissolved Fe in upper-intermediate water (26.6 to 27.0 σθ) derived from the Okhotsk Sea evidently constructs an area that has one of the largest biological CO2drawdowns in the world ocean. These results highlight the pivotal roles of the marginal seas and the formation of intermediate water at the end of the ocean conveyor belt.

show abstract

Section: Methodsmentioning

confidence: 99%

Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation

Nishioka

Obata

Ogawa

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…To avoid measurement of artificial turbulence caused by the frames, the two fast-response thermistors (Fastip Probe model 07; henceforth FP07) were attached close to the bottom of the frames (Fig. 1 of the study 21 ). Probes whose spectra fit the universal spectrum better was used in this analysis.…”

Section: Methodsmentioning

confidence: 99%

Estimation of Basin-scale turbulence distribution in the North Pacific Ocean using CTD-attached thermistor measurements

Goto

Yasuda

Nagasawa

et al. 2021

Sci Rep

Self Cite

View full text Add to dashboard Cite

A recently developed technique for microstructure measurement based on a fast-response thermistor mounted on a conductivity-temperature-depth equipment was used on eight cruises to obtain 438 profiles. Thus, the spatial distribution of turbulent dissipation rates across the North Pacific sea floor was illustrated, and was found out to be related to results obtained using tide-induced energy dissipation and density stratification. The observed turbulence distribution was then compared with the dissipation rate based on a high-resolution numerical ocean model with tidal forcing, and discrepancies and similarities between the observed and modelled distributions were described. The turbulence intensity from observation showed that the numerical model was overestimated, and could be refined by comparing it with the observed basin-scale dissipation rate. This new method makes turbulence observations much easier and wider, significantly improving our knowledge regarding ocean mixing.

show abstract

“…The data were retrieved from the Pacific Ocean (Fig. 1 ) 21 . They comprise profiles, each of which typically extends over a depth of 2000–6000 m below the sea surface, in turn comprising observational bins with width of .…”

Section: Methodsmentioning

confidence: 99%

“…They comprise profiles, each of which typically extends over a depth of 2000–6000 m below the sea surface, in turn comprising observational bins with width of . The turbulent energy dissipation rate for each bin, , is derived by averaging the observational values in the bin, which are estimated from the observed spectrum of the temperature vertical gradient based on the procedure presented in Goto et al 21 , 22 (see Supplementary Information A for the estimation procedure). We restrict our investigation to the intermittency occurring at larger scales, .…”

Section: Methodsmentioning

confidence: 99%

Estimating the population mean for a vertical profile of energy dissipation rate

Sugiura

Kouketsu

Masuda

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

Energy dissipation rates are an important characteristic of turbulence; however, their magnitude in observational profiles can be incorrectly determined owing to their irregular appearance during vertical evolution. By analysing the data obtained from oceanic turbulence measurements, we demonstrate that the vertical sequences of energy dissipation rates exhibit a scaling property. Utilising this property, we propose a method to estimate the population mean for a profile. For scaling in the observed profiles, we demonstrate that our data exhibit a statistical property consistent with that exhibited by the universal multifractal model. Meanwhile, the population mean and its uncertainty can be estimated by inverting the probability distribution obtained by Monte Carlo simulations of a cascade model; to this end, observational constraints from several moments are imposed over each vertical sequence. This approach enables us to determine, to some extent, whether a profile shows an occasionally large mean or whether the population mean itself is large. Thus, it will contribute to the refinement of the regional estimation of the ocean energy budget, where only a small amount of turbulence observation data is available.

show abstract

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

Cited by 21 publications

References 20 publications

Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation

Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation

Estimation of Basin-scale turbulence distribution in the North Pacific Ocean using CTD-attached thermistor measurements

Estimating the population mean for a vertical profile of energy dissipation rate

Contact Info

Product

Resources

About