Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generation of second-mode internal solitary waves during the winter by a
  shoaling internal tide in the northern South China Sea   Field measurements of second-mode internal solitary waves (mode-2 ISWs)
during the winter on the upper continental slope of the northern South China
Sea were reported in Yang et al. (2009), but their generation mechanism remains
elusive. We investigated this issue with a multi-modal evolution model and
theoretical analysis, which suggest that the observed mode-2 ISWs were
generated by a shoaling mode-2 semidiurnal internal tide (IT) that emanated
from the Luzon Strait. The results show that two groups of mode-2 ISWs usually
appear within one semidiurnal tidal period, successively riding on expanded and
subsequently compressed pycnoclines. The number of wave groups largely depends
on the amplitudes of the ITs; that is, a larger IT produces larger mode-2 ISWs.
Furthermore, intermodal coupling dominates the evolution of a mode-1 IT,
highlighting the importance of considering mode scattering in the propagation
of low-mode ITs.

27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex