Papers by Anukul Buranapratheprat
An Oil spill Trajectory model for the South China Sea was applied for use in the Upper Gulf of Th... more An Oil spill Trajectory model for the South China Sea was applied for use in the Upper Gulf of Thailand. The model is based on an assumption that spilled oil will act as a floating object on the sea surface moving in the direction of net forcing composed of Ekman current, Stoke drift motion, residual current, and tidal current. Testing was carried out on July 3, 1999 near Sichang Island and October 15, 1999 in the central part of the Upper Gulf. Laminated drift cards representing an oil slick were released on the sea surface and then tracked. Positions were compared to the computational results from model, with measured wind and tidal current from a hydrodynamic model used as input. Results show agreement, assuming correct tidal current. This model can be modified in the future for oil spill emergency response in shallow seas like the Gulf of Thailand.
The paper described effect of tidal current on oil spill trajectory model. The model, which incor... more The paper described effect of tidal current on oil spill trajectory model. The model, which incorporated the Ekman current, Stoke drift motion, background current and tidal current, has been investigated. A field experiment for testing the model was carried out on March 30, 1995 around Ko Sichang, Thailand. Drift cards were used to represent oil slick. Observed and computed positions of drift cards were compared. The results show that accuracy in trajectory prediction is higher when tidal current computed by hydrodynamic model was included.
MERIS data and Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model coupled with th... more MERIS data and Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model coupled with the Princeton Ocean Model (POM), were used to investigate seasonal variations in surface chlorophyll distributions and their controlling factors to clarify phytoplankton dynamics in the upper Gulf of Thailand. Chlorophyll maps were produced by application on MERIS Level 2 data an empirical algorithm derived from the regression analysis of the relationship between chlorophyll-a concentration and remote sensing reflectance ratio. The results indicated that the patterns of seasonal chlorophyll distributions corresponded to local wind and water circulations. The model simulation highlighted the importance of river water as a significant nutrient source, and its movement after discharge into the sea is controlled by seasonal circulations. High chlorophyll concentration located along the western coast following the direction of counter-clockwise circulation, forced by the northeast winds, while chlorophyll accumulation was observed in the northeastern corner of the gulf due to clockwise circulation, driven by the southwest winds. These key simulated results are consistent with those of field observations and satellite images captured in the same periods of time, and also described seasonal shifting of blooming areas previously reported. Sensitivity analysis of simulated chlorophyll distributions suggested that not only nutrients but also wind-induced vertical movement plays a significant role in controlling phytoplankton growth. Plankton blooms occur in zones of upwelling or where vertical diffusivities are low. Increasing nutrients in the water column due to river loads leads to increasing potential for severe plankton blooms when other photosynthetic factors, such as water stability and light, are optimized. The knowledge of seasonal patterns of blooming can be used to construct environmental risk maps which are very useful for planning to mitigate the eutrophic problems. Effective measures need to be applied to control amount of nutrients released into natural water in order to minimize severity of red tides.
Continental Shelf Research, 2008
Seasonal variation in water column conditions in the upper Gulf of Thailand (UGoT) was analyzed b... more Seasonal variation in water column conditions in the upper Gulf of Thailand (UGoT) was analyzed by considering four major factors including surface heat flux, freshwater discharge, tidal and wind stirrings. The coincidence of surface heat loss, low river discharge and strong wind resulted in vertical well-mixing in December. Strong stratification developed in September and October due to large river discharge
MERIS data and Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model coupled with th... more MERIS data and Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model coupled with the Princeton Ocean Model (POM), were used to investigate seasonal variations in surface chlorophyll distributions and their controlling factors to clarify phytoplankton dynamics in the upper Gulf of Thailand. Chlorophyll maps were produced by application on MERIS Level 2 data an empirical algorithm derived from the regression analysis of the relationship between chlorophyll-a concentration and remote sensing reflectance ratio. The results indicated that the patterns of seasonal chlorophyll distributions corresponded to local wind and water circulations. The model simulation highlighted the importance of river water as a significant nutrient source, and its movement after discharge into the sea is controlled by seasonal circulations. High chlorophyll concentration located along the western coast following the direction of counter-clockwise circulation, forced by the northeast winds, while chlorophyll accumulation was observed in the northeastern corner of the gulf due to clockwise circulation, driven by the southwest winds. These key simulated results are consistent with those of field observations and satellite images captured in the same periods of time, and also described seasonal shifting of blooming areas previously reported. Sensitivity analysis of simulated chlorophyll distributions suggested that not only nutrients but also wind-induced vertical movement plays a significant role in controlling phytoplankton growth. Plankton blooms occur in zones of upwelling or where vertical diffusivities are low. Increasing nutrients in the water column due to river loads leads to increasing potential for severe plankton blooms when other photosynthetic factors, such as water stability and light, are optimized. The knowledge of seasonal patterns of blooming can be used to construct environmental risk maps which are very useful for planning to mitigate the eutrophic problems. Effective measures need to be applied to control amount of nutrients released into natural water in order to minimize severity of red tides.
Journal of Oceanography, 2008
Although plankton bloom incidents in the upper Gulf of Thailand (UGoT) have been reported, no dyn... more Although plankton bloom incidents in the upper Gulf of Thailand (UGoT) have been reported, no dynamic investigation of the phenomenon has been conducted. To address this need, a simple pelagic ecosystem model coupled with the Princeton Ocean Model (POM) was employed to investigate seasonal variations in surface chlorophyll-a (chl-a) distributions to clarify phytoplankton dynamics in this area. The results revealed patterns of seasonal chl-a distribution that correspond to local wind, water movement and river discharge. High chl-a patchiness was found to be concentrated near the western coast following westward circulation near the northern coast developed during the northeast monsoon. During the southwest monsoon high concentrations were observed around the northeastern coast due to eastward flow. The simulated results could explain the seasonal shifting of phytoplankton blooms, which typically arise along the western and eastern coasts during the northeast and the southwest monsoons, respectively. Sensitivity analyses of simulated chl-a distributions demonstrate that water stability, including wind-induced vertical currents and mixing, plays significant roles in controlling phytoplankton growth. Nutrients in the water column will not stimulate strong plankton blooms unless upwelling develops or vertical diffusivity is low. This finding suggests an alternative aspect of the mechanism of phytoplankton bloom in this region.
Continental Shelf Research, 2008
Seasonal variation in water column conditions in the upper Gulf of Thailand (UGoT) was analyzed b... more Seasonal variation in water column conditions in the upper Gulf of Thailand (UGoT) was analyzed by considering four major factors including surface heat flux, freshwater discharge, tidal and wind stirrings. The coincidence of surface heat loss, low river discharge and strong wind resulted in vertical well-mixing in December. Strong stratification developed in September and October due to large river discharge
Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorg... more Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) in the Bangpakong estuary, Thailand were investigated by employing the database obtained in the National Research Council of Thailand (NRCT)-Japan Society for the Promotion of Science (JSPS) cooperative project from 1994 to 1997. The results showed that variation in interaction between coastal sea and river discharge played an important role in controlling the characteristics of the water in the estuary. Residence time of fresh water was short in wet season and dry season, but it was long in the transition period from season to season. DIP and DIN load depended on river discharge, while high peak concentrations were related to loading and the long residence time in the transition period between dry and wet seasons. A strong eutrophic condition could possibly occur when the concentration of DIP and DIN were high during the onset of the wet season from April to July. The annual average of inorganic nutrient budgets indicated that the Bangpakong estuary is the internal source of 38.2 tons/month DIP and the internal sink of 4.9 tons/month DIN.
Journal of Oceanography, 2008
Although plankton bloom incidents in the upper Gulf of Thailand (UGoT) have been reported, no dyn... more Although plankton bloom incidents in the upper Gulf of Thailand (UGoT) have been reported, no dynamic investigation of the phenomenon has been conducted. To address this need, a simple pelagic ecosystem model coupled with the Princeton Ocean Model (POM) was employed to investigate seasonal variations in surface chlorophyll-a (chl-a) distributions to clarify phytoplankton dynamics in this area. The results revealed patterns of seasonal chl-a distribution that correspond to local wind, water movement and river discharge. High chl-a patchiness was found to be concentrated near the western coast following westward circulation near the northern coast developed during the northeast monsoon. During the southwest monsoon high concentrations were observed around the northeastern coast due to eastward flow. The simulated results could explain the seasonal shifting of phytoplankton blooms, which typically arise along the western and eastern coasts during the northeast and the southwest monsoons, respectively. Sensitivity analyses of simulated chl-a distributions demonstrate that water stability, including wind-induced vertical currents and mixing, plays significant roles in controlling phytoplankton growth. Nutrients in the water column will not stimulate strong plankton blooms unless upwelling develops or vertical diffusivity is low. This finding suggests an alternative aspect of the mechanism of phytoplankton bloom in this region.
Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorg... more Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) in the Bangpakong estuary, Thailand were investigated by employing the database obtained in the National Research Council of Thailand (NRCT)-Japan Society for the Promotion of Science (JSPS) cooperative project from 1994 to 1997. The results showed that variation in interaction between coastal sea and river discharge played an important role in controlling the characteristics of the water in the estuary. Residence time of fresh water was short in wet season and dry season, but it was long in the transition period from season to season. DIP and DIN load depended on river discharge, while high peak concentrations were related to loading and the long residence time in the transition period between dry and wet seasons. A strong eutrophic condition could possibly occur when the concentration of DIP and DIN were high during the onset of the wet season from April to July. The annual average of inorganic nutrient budgets indicated that the Bangpakong estuary is the internal source of 38.2 tons/month DIP and the internal sink of 4.9 tons/month DIN.
Journal of Oceanography, 2002
Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorg... more Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) in the Bangpakong estuary, Thailand were investigated by employing the database obtained in the National Research Council of Thailand (NRCT)-Japan Society for the Promotion of Science (JSPS) cooperative project from 1994 to 1997. The results showed that variation in interaction between coastal sea and river discharge played an important role in controlling the characteristics of the water in the estuary. Residence time of fresh water was short in wet season and dry season, but it was long in the transition period from season to season. DIP and DIN load depended on river discharge, while high peak concentrations were related to loading and the long residence time in the transition period between dry and wet seasons. A strong eutrophic condition could possibly occur when the concentration of DIP and DIN were high during the onset of the wet season from April to July. The annual average of inorganic nutrient budgets indicated that the Bangpakong estuary is the internal source of 38.2 tons/month DIP and the internal sink of 4.9 tons/month DIN.
Journal of Oceanography, 2002
Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorg... more Seasonal variations in freshwater, salt, dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) in the Bangpakong estuary, Thailand were investigated by employing the database obtained in the National Research Council of Thailand (NRCT)-Japan Society for the Promotion of Science (JSPS) cooperative project from 1994 to 1997. The results showed that variation in interaction between coastal sea and river discharge played an important role in controlling the characteristics of the water in the estuary. Residence time of fresh water was short in wet season and dry season, but it was long in the transition period from season to season. DIP and DIN load depended on river discharge, while high peak concentrations were related to loading and the long residence time in the transition period between dry and wet seasons. A strong eutrophic condition could possibly occur when the concentration of DIP and DIN were high during the onset of the wet season from April to July. The annual average of inorganic nutrient budgets indicated that the Bangpakong estuary is the internal source of 38.2 tons/month DIP and the internal sink of 4.9 tons/month DIN.
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Papers by Anukul Buranapratheprat