30–75-day Sea Level Variations in The Equatorial Indian Ocean as Observed by Satellite Altimeter
Abstract: Basin-wide structure
of intraseasonal sea level variations in the equatorial Indian Ocean is
investigated using satellite altimeter data. The spectral analysis reveals that the intraseasonal sea level variations are dominated by the
30–75-day oscillations. The spatial amplitude structures of the intraseasonal
sea level inferred from the complex empirical orthogonal function (CEOF)
analysis show a typical structure of equatorial Kelvin and off-equatorial Rossby
waves. Moreover, the spatial phase structures of the CEOF mode reveal eastward
propagating signal. The estimated phase speed does not correspond exactly to
that of one particular baroclinic modes though it falls within the range
expected for the first three baroclinic modes in the Indian Ocean. This may
suggest that the propagating signals do not involve a single baroclinic mode,
but instead the first, second and possibly higher baroclinic modes.
Keywords: Complex empirical
orthogonal function, Indian Ocean, Intraseasonal variations, Kelvin waves,
Rossby waves, Sea level
Author: Iskhaq Iskandar
Journal Code: jpbiologigg110007
