Basic HTML Version
Int. J. of Marine Science 2012, Vol.2, No.7, 51
-
56
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56
variability of the chlorophyll-
a
in regions with
vigorous eddy fields.
2 Data and Methods
Satellite derived (9-km spatial resolution SeaWIFS and
MODIS-Aqua) weekly and monthly Level-3 products
for chlorophyll-
a
concentration were employed, to
assemble time series for the western Arabian Sea
(18~25ºN, 58~62ºE), for the period of 1997~2008.
These products are available from the National
Aeronautics and Space Administration (NASA) Ocean
Color
Group
(http://oceancolor.gsfc.nasa.gov).
Monthly time series were acquired using the
GES-DISC Interactive Online Visualization and
Analysis Infrastructure (GIOVANNI) software as part
of NASA's Goddard Earth Sciences Data and
Information Services Center. Maps for sea surface
height
anomalies
were
produced
from
TOPEX/Poseidon, Jason-1 and Jason-2 altimeter data
and acquired from the Archiving, Validation and
Interpretation of Satellite Oceanographic Data Center
website (
http://www.aviso.oceanobs.com
) and the
CCAR Global Near Real-Time SSH Anomaly/Ocean
Color Data Viewer (
http://argo.colorado.edu/~
realtime/modis/
).
The construction of the kinetic energy time series was
based on the altimeter–derived sea surface heights for
the western Arabian Sea (18º~25ºN, 58º~62ºE), for the
period of 1997~2008. The methodology of calculations
of eddy kinetic energy per unit mass (EKE) was given
by Sharma et al (1999).
The spectral analysis (from the “Statistica” v9 package)
has been applied to estimate dominant periods in
weekly time series of chlorophyll-
a
concentration
(with N=524) and kinetic energy of eddies (with
N=624 and the Hamming window weights: 0.357,
0.241, 0.446, 0.241, 0.357 applied to both parameters).
Author’s Contributions
SP performed the statistical analysis and drafted the manuscript. NN retrieved
time series from appropriate databases and carried out the estimates of the
kinetic energy. All authors read and approved the final manuscript.
Acknowledgement
The present work was supported by the Research Council grant No.
ORG/EBR/09/004 (Sultanate of Oman).
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