Relative Dispersion in the Enstrophy-Cascading Inertial Range of Homogeneous Two-Dimensional Turbulence

Lin, Jung-Tai

doi:10.1175/1520-0469(1972)029<0394:rditec>2.0.co;2

Cited by 78 publications

(53 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this situation the exponent b → ∞ in Eq. (8.12) and an exponential growth of the distance with time (Lin's law) occurs (Lin 1972;Falkovich et al 2001;LaCasce 2008). Thus, for an ideal 2D turbulence with a single energy input scale λ, Lin's law is expected to be valid for scales below λ whereas Richardson's law is related to large-scale circulation (Salazar and Collins 2009).…”

Section: Spreading Rates In the Uppermost Layer Of The Gulf Of Finlandmentioning

confidence: 99%

Evaluation and Tuning of Model Trajectories and Spreading Rates in the Baltic Sea Using Surface Drifter Observations

Kjellsson

Döös

Soomere

2013

Preventive Methods for Coastal Protection

View full text Add to dashboard Cite

Results from experiments with surface drifters in the Baltic Sea in 2010-2011 are presented and discussed. In a first experiment, 12 SVP-B (Surface Velocity Program, with Barometer) drifters with a drogue at 12-18 m depth were deployed in the Baltic Sea. In a second experiment, shallow drifters extending to a depth of 1.5 m were deployed in the Gulf of Finland. Results from the SVP-B drifter experiment are compared to results from a regional ocean model and a trajectory code. Differences between the observed SVP-B drifters and simulated drifters are found for absolute dispersion (i.e., squared displacement from initial position) and relative dispersion (i.e., squared distance between two initially paired drifters). The former is somewhat underestimated since the simulated currents are neither as fast nor as variable as those observed. The latter is underestimated both due to the abovementioned reasons and due to the resolution of the ocean model.For the shallower drifters, spreading in the upper 1-2 m of the Gulf of Finland is investigated. The spreading rate is about 200 m/day for separations <0.5 km, 500 m/day for separations below 1 km and in the range of 0.5-3 km/day for separations in the range of 1-4 km. The spreading rate does not follow Richardson's law. The initial spreading, up to a distance of about d = 100-150 m, is governed by the power law d ∼ t 0.27 whereas for larger separations the distance increases as d ∼ t 2.5 .

show abstract

Section: Spreading Rates In the Uppermost Layer Of The Gulf Of Finlandmentioning

confidence: 99%

Evaluation and Tuning of Model Trajectories and Spreading Rates in the Baltic Sea Using Surface Drifter Observations

Kjellsson

Döös

Soomere

2013

Preventive Methods for Coastal Protection

View full text Add to dashboard Cite

show abstract

“…In this period, the KE spectra has k 23 dependence (Kraichnan and Montgomery 1980) and ky ) 1, so that (12) and (9) give (Lin 1972) s yy 5 exp(C 1 h 1/3 t) and…”

Section: ) Early Timementioning

confidence: 99%

Lateral Mixing in the Pycnocline by Baroclinic Mixed Layer Eddies

Badin

Tandon

Mahadevan

2011

Journal of Physical Oceanography

View full text Add to dashboard Cite

Using a process study model, the effect of mixed layer submesoscale instabilities on the lateral mixing of passive tracers in the pycnocline is explored. Mixed layer eddies that are generated from the baroclinic instability of a front within the mixed layer are found to penetrate into the pycnocline leading to an eddying flow field that acts to mix properties laterally along isopycnal surfaces. The mixing of passive tracers released on such isopycnal surfaces is quantified by estimating the variance of the tracer distribution over time. The evolution of the tracer variance reveals that the flow undergoes three different turbulent regimes. The first regime, lasting about 3-4 days (about 5 inertial periods) exhibits near-diffusive behavior; dispersion of the tracer grows nearly linearly with time. In the second regime, which lasts for about 10 days (about 14 inertial periods), tracer dispersion exhibits exponential growth because of the integrated action of high strain rates created by the instabilities. In the third regime, tracer dispersion follows Richardson's power law. The Nakamura effective diffusivity is used to study the role of individual dynamical filaments in lateral mixing. The filaments, which carry a high concentration of tracer, are characterized by the coincidence of large horizontal strain rate with large vertical vorticity. Within filaments, tracer is sheared without being dispersed, and consequently the effective diffusivity is small in filaments. While the filament centers act as barriers to transport, eddy fluxes are enhanced at the filament edges where gradients are large.

show abstract

“…is the enstrophy dissipation at scales smaller than the forcing scale, k > k f , and an inverse energy-cascade E(k) ~ e 2 ' 3 k' 5/i at scales larger than the forcing scale, k < k { . In the enstrophy cascade regime, exponential particle separation can be expected, rP-(t) = £>j;exp(Ao/), where /"' is the enstrophy cascade time scale (Lin, 1972). Note that the emergence of a dual spectrum in 2D turbulence requires forcing at a narrow range of scales and the spectrum tends toward E{k) ~ k for the more typical oceanic case of broad-band forcing (Lesieur, 1997).…”

Section: (3)mentioning

confidence: 99%