1994 Fiscal Year Final Research Report Summary
The sea dynamics inferred from satellite sequential radiometry images
| Project/Area Number |
05640479
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
OSTROVSKII Alexander g. Kyushu Univ.・Res.Inst.for Appl.Mech., Assc.Prof., 応用力学研究所, 助教授 (70243962)
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| Co-Investigator(Kenkyū-buntansha) |
UMATANI Shinichiro Kyushu Univ.・Res.Inst.for Appl.Mech., Res.Assc., 応用力学研究所, 助手 (30112353)
IMAWAKI Shiro Kyushu Univ.・Res.Inst.for Appl.Mech., Prof., 応用力学研究所, 教授 (40025474)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Sea surface temperature / NOAA satellite / COADS data / Fractal / Wavelet / Inversion / Advection / Diffusion |
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| Research Abstract |
1. The sea surface temperature (SST) data were acquired from the NOAA satellites radiometry surveys and deduced from the Comprehensive Ocean-Atmosphere Data Set Compressed Marine Reports. The Compiled data sets cover the Northwestern Pacific including the Japan Sea. The SST distri-butions represent an indirect result of the turbulence and currents in the upper ocean. The fractal, wavelet and inversion techniques were used to infer the sea dynamics from the sequen-tial fields of the sea surface temperature (SST).
2. For the first time the fractal dimension estimation and two-dimensional orthonormal wavelet transform techniques were applied to the satellite born SST images. The fractal and wavelet analyzes demonstrated the intermittence and multiscale phenomena in the the the Japan Sea surface temperature patterns. (1) The fractal dimension calculations indicated the chaotic behaviorof the upper sea dynamics. (2) The results of the wavelet analysis allowed to suggest that the autumn cooli
… More
ng leads to enhancement of the three dimensional mixing, while at the beginning of thespring heating the stably stratified conditions in the upper sea are favorable for stirring by eddies at scales ofthe geostrophic turbulence.
3. The original inversion methods were deeloped to obtain the sea near-surface velocities and mixing coefficients from time dependent distributions of passive tracers such as SST.(1) The first approach concerned the case of the transient flow. The unknown horizontal velocities, diffusion tensor and decaying rate in a conservation equation for SST are derived by means of a maximum likelihood (ML) estimator. In the numerical simulations it is shown that the ML esti-mator provides us with consistent estimates of the mixing coefficients for different resolu-tions of the data grid. Also it can provide reasonable advection velocities in a certain range of oceanic conditions of general interest. (2) The second approach was devoted to estimate of climatically mean advection-diffusion transport from the long time-series of observations. The unknown parameters were found by fitting a stochastic partial differential temperature conser-vation equation to the observed covariances of the winter SST anomalies over the Northwestern Pacific. The inversion was applied to the SST data averaged at 1deg latitude x 2deg longitude boxes on a 10-day mean basis from 1965 to 1990. The estimates of the net advection velocity are consistent in magnitude and direction with the general circulation in the surface layr of the Northwest Pacific in winter. The estimates of the diffusion coefficient were also reliable. The analysis supports Hasselmann's theory in which generation of midlatitude SST anomalies lasting the dominant timescale of atmospheric processes is primarily attributed to the short period stochastic weather forcing. However, the analysis indicates that the inertia of SST anomalies to their "memory" of earlier winds can not be neglected in the vicinity of the western boundary and in the tropics. Less
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Research Products
(18 results)
