The paper describes a vertical multiple opening and closing plankton sampler (ORI-VMPS) having four nets, lmx lm in mouth opening and 510cm in length with accessories designed for sampling macrozooplankton. The ORI-VMPS is opened and closed at a desired depth by com mand relayed through a conducting cable. Depth of ORI-VMPS is monitored on a recorder. The towing from 2,000m depth requires about 90 minutes. Therefore, it is possible to collect more than ten time-series samples from the deep sea in a single day.

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Using Landsat TM Image of the Kimhae Delta Plain, Korea, this study clarifies the reason why paddy fields make different tones after harvest. In order to examine the brightness difference, the study collected soil samples from areas and analyzed a soil grain size and chemical contents. According to the analyses, the brightness difference could not be explain by the soil moisture, grain size composition and the quantity of organic matters. However, two sample areas showed a clear difference in their saline contents, and the distribution pattern of saline soil and non-saline soil corresponded with the landform development of delta. Therefore, the study concluded that the saline difference is the cause of the bright difference.

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In order to validate wind vectors derived from NSCAT,statistical distributions of wind speeds and directions over the global oceans are investigated by comparing with ECMWF wind data. Histograms of wind speeds and directions are calculated from the Preliminary NSCAT Science Data Products for a period of about one month. For the wind speed, excessive low wind distribution is pointed out by the comparison of histograms with ECMWF winds. A hump at the lower wind speed side of the peak in the histogram of wind speeds is discernible. Shape of the hump varies with the incidence angle. Incompleteness of the pre-launch geophysical model function, SASS-2, tentatively used to retrieve wind vectors from backscatter measurements, is considered to cause the skew of the wind speed distribution. Frequency distribution of the wind directions relative to the spacecraft flight direction is calculated to assess selfconsistency of the wind directions. It is found that the NSCAT-derived wind vectors may exhibit systematic directional preference relative to the antenna beams in comparison with those of the ECMWF winds. This artificial directivity is also considered to be caused by imperfections in the model function. Dependencies of the directional distributions on incidence angle and wind speed are also discussed.

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Dependenceof C-band radar cross-sectionon the sea surface temperature (SST) is statistically investigatedby using sigma-0 observed by the ERS-1/AMIscatterometer with collocated ECMWF wind and temperature data. Negativecorrelation of the sigma-0 with SST is discernible for cases of crosswind, mid wind speedand high incidence angle. The slopeof the linearregression line reaches -0.07dB/°C,whichis not negligible for the windobservation by the C-bandscatterometer. The correlation is not significantfor cases of upwind and downwind incidence or low incidence angle. TheSSTdependence of C-band sigma-0 is discussed in relation withthe temperature de pendence of water viscosity. It is concluded, however, that the SST dependence of the C-band sigma-0 found in the present study may notbe explained by the temperature dependence of vis cosity.

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It is becoming well known that alias effects associated with ocean tides could be a major source of systematic error in altimeter sea level measurements, as a result of asynoptic sampling and imperfect tide models. However, it has been pointed out that signals of non-tidal origin may also contribute a significant part to the observed aliasing (Chen and Ezraty, 1996). In this paper, numerical simulations are performed to demonstrate the full aliasing potential associated with altimeter observations of sea sonal sea level variability and annual Rossby waves. Our results indicate that ignorance of non-tidal aliasing may lead to the possibilities of underestimating the total alias effects and misinterpreting or overlooking existing geophysical phenomena. Therefore, it is argued that an entire aliasing picture should be kept in mind when satellite altimeter data are analyzed.

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Surface layer(0-17 °C isotherm depth) heat balance of a closed rectangular system (the Kuroshio system) in the North-West Pacifichas been examined for a period of 10 days (from 16th to 25th October, 1991), by considering the residual of net surface heat flux and heat divergence of the systemdue to horizontaladvection. The Kuroshio system has been formulated by taking hydrographic sections (CTD) across the lateral boundaries. Net surface heat flux for the system has been obtained exclusively from satellite observations of surface meteorological parameters using bulk method. Heat divergence in the systemis deducedby consideringthe residual heat advection into/out of the system due to geostrophic currents across the lateral boundaries, derived using method of Wunsch (1978). Synoptic flux estimates using satellite observations are compared with earlier estimates for this region (in the same season) from in situ data and are found to be reasonable. While the Kuroshio regime shows large net heat loss, towards the south it decreases and have heat surplus. An evaluation of the satellite derived heat fluxes by comparing with flux estimates from in situ observations at ocean weather station-Tango are also found to be comparable. For net satellite derived heat flux varying from 0 to 300w/m^2 the uncertainties are found to be of the order of 50- 80w/m^2. For the same range of flux values the possible uncertainties in ground based climatological estimates are from 40 to 60w/m^-2. This increase in uncertainties for satellite derived fluxes are found to be due to remote sensing error. For the Kuroshio system, the net heat flux varies from 0-300w/m2 with uncertainties varying from 50 to 80w/m^2. Regarding the heat balance of the Kuroshio box model, the net surface heat flux for the box is -1.4x10^14watt. Though there is a general view that Kuroshio act as an effective feeder for the surface heat loss for this region in the present case it is found that for 10-days mean period this is not hapening. Instead of that the system is also losing heat in terms of advection. The horizontal heat divergence due to advection is -0.6x10^14watt. During the observation period it is seen that the surface layer (nearly 100m) temperature falls down considerably (of the order of 1°C). It is found that the observed surface heat loss alone is not sufficient to cause the fall in the surface layer temperature of such a large system. The observed horizontal heat divergence is largely caused by the mass imbalance rather than the flow temperature difference at the boundaries.

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This paper proposes a new method in sonar signal processing using ”Overlappingsectional synthetic aperture.” This method is developed to provide high azimuth resolution in a synthetic aperture operation evenwhena ship cannotkeepmoving on a straightbaseline.Theaperture direc tion is at first detected with a gyroscope and made parallel to the base line using mechanical feed back system. Signals from the overlapping part of two successive apertures overlapping in the base line direction with the lateral deviation in position are compared and the phase difference between two signals is detected. Signal of non-overlapping part of the second aperture is corrected using thisphase difference. It is possible to obtain much higher azimuth resolution thana realaperture by repeating this procedure. This method does not require to change most of conventional sonar sys tem and the signal processing is performed mostly using Fourier transform. Results of computer simulation prove the effectiveness of this method.

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[in Japanese]

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