Physical characteristics of watermass in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam waters

This study provides new information on the physical characteristics of water masses in Sabah and Sarawak waters. The aim was to determine the effect of Southwest (SW) monsoon on the variability of water masses, in Sabah and Sarawak waters. Physical characteristics data were obtained using an instrument called “Integrated Conductivity Temperature Depth” (iCTD), during the third (July 1996) and fourth (May 1997) cruises of the MV SEAFDEC research vessel, conducted during the SW monsoon season. Vertical distributions and profiles of temperature, salinity and density were analyzed and their variations between the two cruises compared. It is concluded that there were no great variations of temperature, salinity and density values in the study area, during both cruises. This is because both cruises were conducted during the SW monsoon season. However, variations of temperature, salinity and density values were observed between shallow and deep waters, as well as coastal and offshore waters. Based on their vertical distributions and profiles obtained during the two cruises, water properties in shallow waters were found to vary slightly from the deeper ones. As a result, in the southern tip of the South China Sea, where the water was shallow, its properties here differed a little from the rest of the study area. This was due to the pronounced mixing effect of surface waves in shallow waters. At the same time, lower salinity and consequently, lower density values were detected in coastal waters, resulting from of the influx of freshwater from Sabah and Sarawak rivers during this monsoon season

Distributions of temperature and dissolved oxygen in the Terengganu estuary

This study provides new information on both the temperature and dissolved oxygen (DO) distributions in the Terengganu estuary. Temperature and DO were measured, along the Terengganu estuary and her two rivers, once a month for 12 months, using a Hydrolab multi-parameter probe. This is to determine the response of both temperature and DO distributions to seawater intrusion in the Terengganu estuary. Our results show that water is cooler upstream and the temperature increases downstream towards the mouth of the estuary. The highest water temperature is recorded in June (29.40°C), while the lowest water temperature is detected in January (25.84°C). We concluded that the temperature distribution in Terengganu estuary and both the rivers, is influenced directly by the monsoon seasons. DO values in the Terengganu estuary are generally high (5-6 mg/l) throughout the year except in August (3-4 mg/l). The values tend to increase from the estuary towards the sea from April to July, but the trend reverses from September to December. Therefore, two transitional stages can be identified. The first transitional stage starts from January to March (where seawater gradually intrudes the Terengganu estuary) and the second transitional stage occurs in August (where seawater gradually retreats from the Terengganu estuary). Thus, the DO distribution in the Terengganu estuary and both the rivers is influenced directly by seawater intrusion

Distributions of temperature and dissolved oxygen in the Terengganu estuary

This study provides new information on both the temperature and dissolved oxygen (DO) distributions in the Terengganu estuary. Temperature and DO were measured, along the Terengganu estuary and her two rivers, once a month for 12 months, using a Hydrolab multi-parameter probe. This is to determine the response of both temperature and DO distributions to seawater intrusion in the Terengganu estuary. Our results show that water is cooler upstream and the temperature increases downstream towards the mouth of the estuary. The highest water temperature is recorded in June (29.40°C), while the lowest water temperature is detected in January (25.84°C). We concluded that the temperature distribution in Terengganu estuary and both the rivers, is influenced directly by the monsoon seasons. DO values in the Terengganu estuary are generally high (5-6 mg/l) throughout the year except in August (3-4 mg/l). The values tend to increase from the estuary towards the sea from April to July, but the trend reverses from September to December. Therefore, two transitional stages can be identified. The first transitional stage starts from January to March (where seawater gradually intrudes the Terengganu estuary) and the second transitional stage occurs in August (where seawater gradually retreats from the Terengganu estuary). Thus, the DO distribution in the Terengganu estuary and both the rivers is influenced directly by seawater intrusion

Physical Characteristics of Watermass in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam Waters

This study provides new information on the physical characteristics of water masses in Sabah and Sarawak waters. The aim was to determine the effect of Southwest (SW) monsoon on the variability of water masses, in Sabah and Sarawak waters. Physical characteristics data were obtained using an instrument called “Integrated Conductivity Temperature Depth” (iCTD), during the third (July 1996) and fourth (May 1997) cruises of the MV SEAFDEC research vessel, conducted during the SW monsoon season. Vertical distributions and profiles of temperature, salinity and density were analyzed and their variations between the two cruises compared. It is concluded that there were no great variations of temperature, salinity and density values in the study area, during both cruises. This is because both cruises were conducted during the SW monsoon season. However, variations of temperature, salinity and density values were observed between shallow and deep waters, as well as coastal and offshore waters. Based on their vertical distributions and profiles obtained during the two cruises, water properties in shallow waters were found to vary slightly from the deeper ones. As a result, in the southern tip of the South China Sea, where the water was shallow, its properties here differed a little from the rest of the study area. This was due to the pronounced mixing effect of surface waves in shallow waters. At the same time, lower salinity and consequently, lower density values were detected in coastal waters, resulting from of the influx of freshwater from Sabah and Sarawak rivers during this monsoon season