Water Mass Characteristics and Stratification at the Shallow Sunda Shelf of Southern South China Sea

Abstract

CTD data obtained from two oceanographic cruises during June and October 2012 were used to define the water mass characteristics and degree of stratification at the shallow Sunda shelf located at the southern South China Sea. The water masses during both cruises showed characteristics similar (southwest monsoon) to those observed in the adjacent regions. A clustering method was used in which three water masses were classified from the composite dataset. There are WM1 (T 29˚C-31˚C, S 32-33.5 psu, & σT, ~19.5-20.7 kg/m 3), WM2 (T 25˚C-29˚C, S 32.8-33.8 psu, & σT, ~22.3-23 kg/m 3) and WM3 (T 23˚C-25˚C, S 33.5-34.0, & σT ~22.3-23.3 kg/m 3). Even though the water masses found were characterized under southwest monsoon characteristics, the degrees of stratification obtained varied between these cruises. The stability of the stratification also plays roles in the distribution of the water masses in the water column. WM2 was found in thermocline layer and most dominant in June compared to in October. In June, WM3 was found under the thermocline layer and absent in October. The stable thermocline caused the denser WM3 cannot mixed with WM2. Higher temperatures and weaker winds during June may have caused the strong stratification, while decreasing temperature and stronger winds of an upcoming northeast monsoon enhanced the vertical mixing during October.

Transformation and mixing of North Pacific Water Mass in Sangihe-Talaud in August 2019

“…If there is no stratification, the fluid becomes unstable so that the vertical fluid displacement is further away from the initial position. The frequency value close to zero (N≈0) does not represent loss of stratification in total, but the stratification weakened due to mixing [24]. The N profile is affected by the vertical profile of temperature and potential density (σθ).…”

Physical Properties of Seawater in Malacca Strait (Southeast Asia) during Monsoon Seasons

“…Most water masses are SWW masses that formed in the surface area. This results from the vast amount of fresher water in MS that reduces the density of seawater compared with other regions like SCS (Roseli et al ., 2015). August did not show SW mass (the densest water mass) because of less stratification.…”

“…The last part of the equation, Δ p , is derived from the hydrostatic relation of P z , which is – gp . In terms of static stability in the ocean, stratification is stable and does not overturn locally if N 2 > 0 (Roquet et al ., 2015; Roseli et al ., 2015).…”

“…In terms of static stability in the ocean, stratification is stable and does not overturn locally if N 2 . 0 (Roquet et al, 2015;Roseli et al, 2015).…”

Simulating a Sea Wave Power Plant for Malaysia

“…Power generated by the sea wave power plant is shown in the Eq. ( 5) where the Real Plant with length is 𝐿 [𝑚] and the efficiency of sea wave power plant is 𝑛 𝑤 [2][3][4][5][6][7][8][9][10][11][12][13][14].…”