Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Key Modes for Time-Space Evolutions of ENSO and PDO by ESMD Method   The relation between El Ni\~{n}o-Southern Oscillation (ENSO) and Pacific
Decadal Oscillation (PDO) perplexes the researchers. Probably, this is due to
the default choice on empirical orthogonal function (EOF) method whose outputs
are merely static maps without evolution characteristics. To change this
situation, the new extreme-point symmetric mode decomposition (ESMD) method is
tried. It reveals that: (1) As the ENSO concerned, the key modes are the
quarter-decadal and half-decadal ones; (2) As the PDO concerned, the key modes
are the half-decadal, decadal and interdecadal ones; (3) The half-decadal mode
can be seen as a mutual component for ENSO and PDO and it plays a key part in
the so-called "ENSO-like" variation of PDO. In addition, an integrated version
of ESMD is developed for time-space evolution. Its outputs have verified the
warm-cold shiftings of ENSO and PDO for the most typical episode during
1997-2000.

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The categories of this paper are: math
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The categories of this paper are: cond-mat
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The categories of this paper are: astro-ph
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: stat
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The categories of this paper are: adap-org