Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface Mixing by Geostrophic Flows in the Bay of Bengal   Mixing in the Bay of Bengal, driven by altimetry derived daily geostrophic
surface currents, is studied on subseasonal timescales. Hovm{\"o}ller and
wavenumber-frequency diagrams with power spectra confirm the multiscale nature
of the flow. Advection of bands immediately brings out the chaotic nature of
mixing in the Bay via repeated straining and filamentation of the tracer field.
A principal finding is that mixing is local, i.e., of the scale of the eddies,
and does not span the entire basin. Indeed, Finite Time Lyapunov Exponent
(FTLE), Relative Dispersion (RD) and Finite Size Lyapunov Exponents (FSLE) maps
in all seasons are patchy with minima scattered through the interior of the
Bay. Non-uniform stirring of the Bay is reflected in long tailed histograms of
FTLEs, that become more stretched for longer time intervals. Quantitatively,
advection for a week shows the mean FTLE lies near 0.15-0.16 $day^{-1}$, while
extremes reach almost 0.5 $day^{-1}$. Averaged over the Bay, RD initially grows
exponentially, this is followed by a power-law at scales between approximately
100 and 250 $km$, which finally transitions to an eddy-diffusive regime. These
findings are confirmed by FSLEs; in addition, below 250 $km$, a scale dependent
diffusion coefficient is extracted, while above 250 $km$, eddy-diffusivities
range from $6 \times 10^3$ - $10^4$ $m^2/s$. Finally, with satellite salinity
data, these Lagrangian tools are used in the analysis a single post-monsoonal
fresh water mixing event. Here, FTLEs and FSLEs allow the identification of
transport barriers, and elucidate how eddies help preserve the identity of
fresh water.

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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn