漁民と市民の協働

The desirable coproduction by fishermen and citizens for the creation of Satoumi is discussed on the basis of some examples

Sea level variations of both the South China Sea and the Malacca Straits due to the Northeast and the Southwest Monsoons

Monthly sea level variations in Peninsular Malaysia and Sabah are studied. Previous results are confirmed. However, due to the fact that this is the first study involving such a large number of stations, a clearer understanding of the dynamics of mean sea level variations at selected port of Peninsular Malaysia and Sabah is attained. It is shown that Johor Bahru may be identified as having an east coast pattern.El promedio mensual del nivel del mar en la península malaya y Sabah es motivo de estudio. Una mejor interpretación de la dinámica de la variación del nivel medio del mar se obtiene al estudiarse records (prolongados) de análisis de mareas de varias estaciones portuarias. Lo novedoso de nuestro trabajo es que se demuestra que Johor Bahru responde al régimen de la costa este.Asociación Argentina de Geofísicos y Geodesta

Observation of temperature and velocity in the coastal water off Kuala Terengganu, Malaysia

Mooring observation of current and temperature was made at 17.8 m layer of 19 m depth about 8 km east to Kuala Terengganu, Peninsular Malaysia. Harmonic analysis was applied to tidal currents for 30 days in September 1993, and to the tides observed at Chendering. The K1 tide was the largest both in tidal currents and the tides. Daily mean temperature, currents, sea level, and winds were analyzed from September 1993 to May 1994. Northeast Monsoon from December to February caused sea level rise of 50 cm and temperature lowering of 1°C

Numerical experiment on the sedimentation in Manila Bay

Sedimentation process of suspended matter in Manila Bay supplied from Pampanga River, Pasig River and open ocean is investigated using a three-dimensional numerical model which includes tidal current, residual flow and current due to wind waves. The calculation results well reproduced the major characteristics of the observed sedimentation patterns of silt and clay. The calculation results reveal that the seasonal variability of deposited clay distribution is larger than that of silt in Manila Bay. The area that cysts can accumulate is discussed with the use of the calculation results of clay

Seasonal variation of residual flow in the east sea

A diagnostic three-dimensional numerical model has been established in order to reveal the seasonal variation of residual flow, including wind-driven current, density-driven current and tide-induced residual current, in the East Sea. The observed data on water temperature, salinity (from JODC, 1930-1996) and wind (from GOADS, 1961-1991) were exploited in this study. Residual flows in 4 seasons (spring, summer, autumn and winter) were simulated. Furthermore, the contribution of each component, wind-driven, density-driven and tide-induced residual current, was evaluated. On the basis of the obtained results, it is shown that the wind-driven current plays an important role in the basin-wide circulation in the East Sea, especially in the surface layer. At the lower levels, the density-driven current becomes more significant. The tide-induced residual current is relatively small

Seasonal variability of water quality at Hurun Bay, southern coastal area of Sumatra, Indonesia

The seasonal variability of the water quality at Hurun Bay, the southern coastal area of Sumatra, Indonesia was investigated based on the data of physical (temperature, salinity, transparency), chemical (pH, DO, BOD5, TOM, DIN, DIP) and biological (plankton) parameters during 2001-2004. The observation results show that the water quality at Hurun Bay has changed toward the eutrophication. The gradual increment of the organic mater seems to have influenced on the decreasing of water transparency and DO, and the increasing of DIN and TOM. The main factors of the organic enhancement at Hurun Bay were the aquaculture activities, precipitation, mixing and coastal upwelling. Seasonal variability of water quality at Hurun Bay was associated with the monsoonal system in which high precipitation and warm water throughflow during the northwest (NW) monsoon caused increasing water temperature and DIN, generated phytoplankton bloom, and decreased salinity and transparency. The horizontal and vertical mixing in both transition periods of northwest to southeast monsoon (Tr-I) and its reverse (Tr-II), and coastal upwelling in the transition period of SE to NW (Tr-II) have caused decreasing water temperature and transparency, and increasing salinity, DIN and DIP. Water temperature and precipitation are the important parameters for phytoplankton bloom in Hurun Bay. The diatom (chaetoceros, rhizosolenia, nitzschia and bacteriastum) and dinophyceae (ceratium, protoperidinium and pyrodinium) were the most dominant species phytoplankton at Hurun Bay

Influence of local wind field on seasonal circulations in the upper Gulf of Thailand

Previous results of circulation in the upper Gulf of Thailand using a 2-dimensional model suggested counter-clockwise circulation and a clockwise gyre during the northeast and the southwest monsoons, respectively. A review of previous reports relevant to circulation, and the results of surface chlorophyll-a distribution estimated by OCTS (Ocean Color and Temperature Scanner) data support the results during the northeast monsoon. Anyway, residual circulation analyzed from oceanographic buoys deployed in the upper gulf illustrated both clockwise and counter-clockwise circulations during the southwest monsoon. Therefore, the objective of this study is trying to investigate the current patterns and their controlling factors especially during the southwest monsoon. The 2-dimenional circulation model is applied again but this time uses meteorological wind data from local stations around the study area as inputs. The experiments also include investigation of current patterns due to the difference of wind gradients in east-west and north-south direction. The results show that counter-clockwise circulation can be developed during the southwest monsoon when wind magnitude in the east or the south is significantly stronger than that in the west or the north, respectively, which possibly happens in the real situation. It can be concluded that the circulation patterns in the area are controlled by not only wind direction but also its gradient. We also found that external flows through the open boundary can change the patterns of circulation just in the southernmost area

Sea level variations of both the South China Sea and the Malacca Straits due to the Northeast and the Southwest Monsoons

Monthly sea level variations in Peninsular Malaysia and Sabah are studied. Previous results are confirmed. However, due to the fact that this is the first study involving such a large number of stations, a clearer understanding of the dynamics of mean sea level variations at selected port of Peninsular Malaysia and Sabah is attained. It is shown that Johor Bahru may be identified as having an east coast pattern.El promedio mensual del nivel del mar en la península malaya y Sabah es motivo de estudio. Una mejor interpretación de la dinámica de la variación del nivel medio del mar se obtiene al estudiarse records (prolongados) de análisis de mareas de varias estaciones portuarias. Lo novedoso de nuestro trabajo es que se demuestra que Johor Bahru responde al régimen de la costa este.Asociación Argentina de Geofísicos y Geodesta

The Modification of Water Column Conditions in the Gulf of Thailand by the Influences of the South China Sea and Monsoonal Winds

Water column conditions in the Gulf of Thailand (GoT) were analyzed by considering four major factors including surface heat fluxes, freshwater inputs from river discharge and atmospheric fluxes, tidal and wind stirrings. The analytical results suggested that surface heat fluxes and tidal stirring are the most important factors to control water column conditions, followed by freshwater fluxes. Well-mixing was predicted to occur from November to February resulted from relatively large tidal stirring, surface heat loss and low freshwater input, but the climatological density data suggested stratification during this period because of local freshwater accumulation. The South China Sea (SCS) and the northeast wind played significant contributions to freshwater accumulation by generating surface water flow into the gulf during the northeast monsoon. On the other hand, the development of stable and strong stratification during the southwest monsoon was enhanced by SCS subsurface water intrusion and surface outflow induced by the southwest wind. Strong surface heat fluxes coincident with SCS intrusion in April and May make water stratification more complex. This phenomenon generates double thermocline and multi stratified water in some GoTarea