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European Geophysical Society (EGS), XXIV General Assemblies,
Hague, Netherlands, 19-23 April 1999
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Researches of Wave Nature Cyclonic
Eddy Gulf Stream by Hydrological Measurements and Satellite Altimetry Data
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Russian
Version this Page
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In November 1987 near island Newfoundland quasistationary
meander Gulf Stream was beginning to form cyclonic eddy. The wave analysis
of his nature conducted by results of hydrological measurements (temperature
and salinity), spent on this region in time experiment NEWFAUEXP-88 (November
1987 - April 1988).
Shelf wave length was determined by isotherm 16 oC
on horizon 200 m and has made 300 km. Double Kelvin length wave was determined
as double distance between eddy fluctuation and has made 100 km. The spectral
analysis of dynamic topography, designed on GEOSAT satellite altimetry
data along of tracks, which cross eddy for several ERM cycles for this
temporary interval, has shown change of length of a wave from 180 km up
to 150 km for period February - March 1988. The reduction of wave length
in the beginning of spring is caused by decrease of eddy energy.
Such long waves are found out only on data of ascending tracks,
which cross Gulf Stream. Their absence on descending tracks entitles to
assume, that the reason of occurrence of similar waves is barotropic instability
of a main flow, and they are the gear of energy transfer for cyclonic eddy.
© Geophysical Center RAS, 1999 |