South China Sea Circulation Research Articles

Contributions of Wind, Ocean Intrinsic Variability, and ENSO to the Interannual Variability of the South Vietnam Upwelling: A Modeling Study

AbstractThe summer South Vietnam Upwelling (SVU) is a major component of the South China Sea circulation where it also influences ecosystems. Here we revisit the existing knowledge of the SVU interannual variability. Based on a set of 15‐year eddy‐resolving sensitivity simulations, we quantify the respective contributions from different factors (atmospheric, river, and oceanic forcings; ocean intrinsic variability; and El Niño Southern Oscillation) to this interannual variability and explore the underlying mechanisms. Our sea surface temperature upwelling indices allow us to quantify the strong SVU interannual variability in terms of strength and spatial distribution. Strong SVU years are offshore dominant with SVU centers located within 11–12°N and 110–112°E, whereas weak SVU years are coastal dominant with SVU centers located near the coast and spanning a larger 10–14°N latitude range. Our study confirms the leading influence of the summer wind and further reveals that coastal SVU variability is related to the variability of the eastward jet that develops from the coast, whereas offshore SVU variability is strongly driven by the spatiotemporal collocation of wind stress curl with cyclonic eddies. Ocean intrinsic variability, and to a lesser extent perturbations induced by river discharge and lateral oceanic conditions, strongly triggers interannual variability of background eddy circulation, thus of the SVU. El Niño Southern Oscillation influences the SVU mainly through its direct influence on summer winds.

Exploring the Importance of the Mindoro‐Sibutu Pathway to the Upper‐Layer Circulation of the South China Sea and the Indonesian Throughflow

AbstractUsing a high‐resolution (0.1° × 0.1°) regional ocean model, this study investigates the impact of strait transport variability on the South China Sea (SCS) circulation and Indonesian throughflow, with a focus on the Mindoro‐Sibutu pathway via the Sulu Sea, upon closing various straits within the Maritime Continent. Closing the Sibutu Strait reduces the Luzon Strait throughflow into the SCS by 75%, and the Mindoro–Sibutu deep exchange is reversed, thus flowing into the SCS. No significant change occurs over the shallow Sunda Shelf of the southern SCS, which is primarily driven by local monsoon winds. The impact of closing the Karimata Strait is limited to the Sunda Shelf and the Java Sea. The Sibutu Strait throughflow is fundamental in governing the SCS's low salinity, buoyancy, and upper layer injection into the Makassar Strait, which is the primary component of the Indonesian throughflow, thus inhibiting the transport within the upper 200 m of the throughflow. Closing both the Sibutu and Karimata Straits increases the southward Makassar Strait throughflow transport by ~3 Sv, which is derived entirely from the Mindanao Current.

Formation of an anticyclonic eddy and the mechanism involved: a case study using cruise data from the northern South China Sea

Data from satellite altimetry and in situ observations together with the Hybrid Coordinate Ocean Model (HYCOM) reanalysis data were used to investigate the mechanism and formation of an anticyclonic eddy in the northeastern South China Sea (SCS). Analysis of water mass using cruise data indicated that the water captured in the eddy differs from those in the SCS, the Kuroshio intrusion, and the eddy-forming region. Data from sea surface height (SSH) and sea level anomaly (SLA) indicate that the eddy formed due both to the Kuroshio intrusion and the local circulation in the SCS. The Kuroshio intrusion is present at the start of the eddy growth (March 5-9) before Kuroshio leaps the Luzon Strait. The eddy then becomes larger and stronger in the absence of the Kuroshio intrusion. From the eddy budget of the HYCOM reanalysis data, the formation of the eddy goes in three steps. By the third step, the eddy had become affected by variations of local SCS circulation, which is more strongly than in the first step in which it is affected more by the Kuroshio intrusion. The variability of the temperature and salinity inside the eddy provide a support to this conclusion. The water in the SCS intruded into the eddy from the southeast, which decrease the salinity gradually in the southern part of the eddy during the growth period.

Layered model and insights into the vertical coupling of the South China Sea circulation in the upper and middle layers

By changing the calculation of the pressure gradient, we convert a 3.5-layer model to a 3-layer model that includes entrainment and detrainment as well as interfacial friction between layers. In comparison with the reanalysis and satellite altimetry data, the model can well reproduce the circulation and reveal the primary dynamics in the South China Sea. We then use the 3-layer model to investigate the vertical coupling of the South China Sea circulation in the upper and middle layers. It is found that the horizontal pressure gradient, which reflects the depth-integrated effect of the thickness variation across all layers, plays a key role in the dynamical link between layers. Perturbations induced by changing the monsoonal wind or the Kuroshio in two comparative experiments are able to excite cyclonically propagating, slope-trapped waves and the westward planetary Rossby waves to modulate the basin wide circulation in all layers, indicating the dynamically similar adjustments throughout the water column in the SCS in both experiments. Even though the interface frictional dissipation and the entrainment/detrainment induced momentum exchange are small, analysis suggests that the exchange velocity between layers, which varies as the waves pass by, contributes considerably to the redistribution of the layer thickness hence the pressure gradient field in each layer to regulate the variability of the SCS circulation.

Interannual variation of the South China Sea circulation during winter: intensified in the southern basin

Surface geostrophic current derived from altimetry remote sensing data, and current profiles observed from in-situ Acoustic Doppler Current Profilers (ADCP) mooring in the northern South China Sea (NSCS) and southern South China Sea (SSCS) are utilized to study the kinetic and energetic interannual variability of the circulation in the South China Sea (SCS) during winter. Results reveal a more significant interannual variation of the circulation and water mass properties in the SSCS than that in the NSCS. Composite ananlysis shows a significantly reduced western boundary current (WBC) and a closed cyclonic eddy in the SSCS at the mature phase of El Nino event, but a strong WBC and an unclosed cyclonic circulation in winter at normal or La Nina years. The SST is warmer while the subsurface water is colder and fresher in the mature phase of El Nino event than that in the normal or La Nina years in the SSCS. Numerical experiments and energy analysis suggest that both local and remote wind stress change are important for the interannual variation in the SSCS, remote wind forcing and Kuroshio intrusion affect the circulation and water mass properties in the SSCS through WBC advection.

Multidecadal Changes of Upper-Ocean Thermal Conditions in the Tropical Northwest Pacific Ocean versus South China Sea during 1960–2015

Abstract By analyzing the upper-ocean properties of observation-based hydrographic data and validated oceanic reanalysis products, this study presents multidecadal changes of oceanic surface and subsurface thermal conditions in the tropical northwest Pacific Ocean (TNWP) and South China Sea (SCS) during 1960–2015. The analysis reveals that a transition of a 30-yr trend took place in 1980s during the analyzed period for both the surface and subsurface environment. Generally, the warming trend of sea surface temperature (SST) in the TNWP has a similar multidecadal change to that in the SCS. However, a huge accumulating rate of upper-ocean heat content above the 26°C isotherm (UOHC26) showed up in the TNWP (about 3 times compared to that in the SCS) in the last 30 years. In the TNWP, the southward shift of the North Equatorial Current on the multidecadal time scale induces the vertical displacement of isotherms, leading to a strong subsurface warming around the top of the thermocline. Secondarily, the Pacific decadal oscillation (PDO)-related SST regulates the thermal structure in the mixed layer. The multidecadal UOHC26 in the SCS is mainly attributed to the PDO-related SST and further modulated by the isothermal variability caused by the change of basin-scale SCS circulation.

Selective Response of the South China Sea Circulation to Summer Monsoon

AbstractThe response of the South China Sea (SCS) circulation to intraseasonal variability of the summer monsoon is studied with both observations and a 1.5-layer reduced-gravity model. Intraseasonal variability of the SCS summer monsoon is characterized by evolution of the wind jet intensity in the midbasin with typical amplitude of 6 m s−1 and several peaks on its power spectrum between 10 and 60 days. However, this study finds that intraseasonal variability of the sea surface height (SSH) in the SCS presents significant variability to the southeast of Vietnam with amplitude of 6 cm and a period only between 40 and 60 days. This implicates the frequency selectivity of oceanic response to wind forcing. Numerical experiments suggest that the intrinsic variability of the SCS circulation accounts for this phenomenon. Based on the Rossby basin mode theory, this is explained by the interaction between the long, westward-propagating Rossby waves and the short, eastward-propagating Rossby waves.

The influence of ENSO on an oceanic eddy pair in the South China Sea

AbstractAn eddy pair off the Vietnam coast is one of the most important features of the summertime South China Sea circulation. Its variability is of interest due to its profound impact on regional climate, ecosystems, biological processes, and fisheries. This study examines the influence of the El Niño–Southern Oscillation (ENSO), a basin‐scale climatic mode, on the interannual variability of this regional eddy pair using satellite observational data and historical hydrographic measurements. Over the last three decades, the eddy pair strengthened in 1994 and 2002, and weakened in 2006, 2007, and 2008. It was absent in 1988, 1995, 1998, and 2010, coinciding with strong El Nino‐to‐La Nina transitions. Composite analyses showed that the strong transition events of ENSO led to radical changes in the summer monsoon, through the forcing of a unique sea surface temperature anomaly structure over the tropical Indo‐Pacific basin. With weaker zonal wind, a more northward wind direction, and the disappearance of a pair of positive and negative wind stress curls, the eastward current jet turns northward along the Vietnam coast and the eddy pair disappears.

Toward downscaling oceanic hydrodynamics – suitability of a high-resolution OGCM for describing regional ocean variability in the South China Sea

Summary We suggest to transfer the empirical downscaling methodology, which was developed mostly for atmospheric dynamics and impacts, to regional ocean problems. The major problem for doing so is the availability of decades-long and homogeneous and spatially detailed data sets. We have examined the performance of the STORM multidecadal simulation, which was run on a 0.1° grid and forced with 1950–2010 NCEP re-analyses, in the South China Sea and found the data suitable. For demonstration we build with this STORM-data downscaling model for the regional throughflow. The STORM data is compared with AVISO satellite observations and the ocean re-analysis dataset C-GLORS. We find the seasonal patterns and the inter-annual variability of sea surface height anomaly in both the C-GLORS data and the STORM simulation consistent with the AVISO-satellite data. Also the strong westward intensification and the seasonal patterns of South China Sea circulation steered by the monsoon have been presented well. As an important indicator of vertical movement, the sea surface temperature distribution maps are also very close, especially for the narrow upwelling region in summer. We conclude that the output of the STORM simulation is realistically capturing both the large-scale as well as the small-scale dynamical features in the South China Sea.

Observed evidence of the anomalous South China Sea western boundary current during the summers of 2010 and 2011

AbstractSeven years of directly measured current data from a mooring in the Xisha area of the South China Sea (SCS), together with shipboard ADCP and satellite data, have shown the western boundary current (WBC) anomaly and its vertical structure during the summers of 2010 and 2011. The observed WBC presented obvious year‐to‐year variability, especially in the summer. Overall, the summer mean velocity at the mooring site over 7‐year (2007–2013) was northeastward. The moored ADCP showed that the northeastward velocity was particularly strong in the summer of 2010, but the increase was confined in the upper 120 m. In contrast, the northeastward current disappeared throughout the observed depth range (from 50 to 450 m) in the summer of 2011. Even at the deepest observed position, the monthly velocity anomalies reached 14 cm s−1 westward and 12 cm s−1 southward in the zonal and meridional directions, respectively. Both the Vietnam offshore current (VOC) and double gyres in the western SCS disappeared and the southern anticyclonic gyre expanded to strengthened the northward WBC in the summer of 2010. However, in summer of 2011, the VOC intensified, and the northern cyclonic gyre enlarged with its northern edge reaching 18°N, slightly north of mooring site, which weakened the northeastward WBC. The observed SCS circulation anomalies during 2010 and 2011 were mainly induced by the basin‐scale wind field anomalies associated with the 2009/2010 El Niño and 2010/2011 La Niña.

The anticyclonic circulation in the southern South China Sea: Observed structure, seasonal development and interannual variability

In situ hydrographic and current observations from cruises in 1998 and 1999, together with 20-year (1993–2012) sea level anomaly (SLA) data from satellite altermeter, have been used to study the vertical structure, seasonal development, and interannual variability of the anticyclonic circulation in the southern South China Sea (SCS). The relationship between the anticyclonic circulation and its northern flanking cyclonic eddy are described. Three associated circulation patterns are identified. The anticyclonic circulation is present for an average of 108±30days per year, while its northern flanking cyclonic eddy is present for an average of 54±25days per year. The intraseasonal variability of the anticyclonic circulation is intense as a result of advection with the flanking northern cyclone, which accompanies the gyre on average about 60% of the time. The vertical structure of the anticyclonic circulation in 1998 (1999) penetrated much deeper, and its horizontal scope became wider in June (July) than in April. The anticyclonic circulation shows some difference between 1998 and 1999, displaying earlier appearance, more northward position, and non-dipole pattern in 1998, suggesting that the interannual variability of the anticyclonic circulation is related to El Niño Southern Oscillation (ENSO) events. The effect of Sverdrup balance via westward propagating Rossby wave on the seasonal development of the anticyclonic circulation has been discussed.

Low-Frequency Variability of Monsoon-Driven Circulation with Application to the South China Sea

AbstractThe interannual variability of the upper-ocean circulation forced by seasonally varying monsoonal wind is investigated in a two-layer quasigeostrophic (QG) model, with the aim to understand the low-frequency variability of the South China Sea (SCS) circulation. It is demonstrated that the seasonally varying monsoonal wind can force the upper-ocean circulation with significant internal variability, which is mainly associated with the intrinsic nonlinear dynamics of the summer double-gyre system. This arises from the fact that the intrinsic variability, characterized by the Rossby wave adjustment in the winter single-gyre system, is much weaker than that in the summer double-gyre system driven by the intergyre eddy potential vorticity flux through barotropic instability.

Water mass transport through the northern Bashi Channel in the northeastern South China Sea affects copepod assemblages of the Luzon Strait

Abstract Background It is controversial to what extent the intrusion of the Kuroshio Branch Current to the Luzon Strait and the South China Sea circulation can shape copepod assemblages around southern Taiwan. We tested the hypothesis that currents such as the Kuroshio Current bring marine zooplankton and copepods from subtropical and tropical waters to the south of Taiwan. We studied copepod assemblages from the Bashi Channel in the northeastern South China Sea at the coast of southwest Taiwan during early October 1996. Results A total of 77 copepod species were identified from 34 genera that included calanoids, cyclopoids, harpacticoids, and poecilostomatoids. Several indicator species suggest that the study area is highly influenced by water masses from the northern South China Sea as well as from the Kuroshio Current. Acrocalanus gracilis (Paracalanidae, Calanoida) was most abundant (with a relative abundance (RA) of 22.07 and an occurrence rate (OR) of 100%), followed by Paracalanus aculeatus (Paracalanidae, Calanoida) and Oncaea venusta (Cyclopoida). The stations close to the Kuroshio Current showed a higher species diversity (H') and a higher species richness with 3.9 to 4.6 at moderate abundance, whereas station 11 showed lowest species diversity (H') with (2.1), accompanied by the far lowest species number (14) and abundance (880 ind./100 m3). Conclusions Several indicator species suggest that the study area is highly influenced by water masses from the northern South China Sea as well as from the Kuroshio Current.

Summer circulation structure and formation mechanism in the Beibu Gulf

Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea (SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait (QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.

Responses of the circulation and water mass in the Beibu Gulf to the seasonal forcing regimes

In the past 20 a, the gulf-scale circulation in the Beibu Gulf has been commonly accepted to be driven by a wind stress or density gradient. However, using three sensitive experiments based on a three-dimensional baroclinic model that was verified by observations, the formation mechanisms were revealed: the circulation in the northern Beibu Gulf was triggered by the monsoon wind throughout a year; whereas the southern gulf circulation was driven by the monsoon wind and South China Sea (SCS) circulation in winter and summer, respectively. The force of heat flux and tidal harmonics had a strong effect on the circulation strength and range, as well as the local circulation structures, but these factors did not influence the major circulation structure in the Beibu Gulf. On the other hand, the Beibu Gulf Cold Water Mass (BGCWM) would disappear without the force of heat flux because the seasonal thermocline layer was generated by the input of heat so that the vertical mixing between the upper hot water and lower cold water was blocked. In addition, the wind-induced cyclonic gyre in the northern gulf was favorable to the existence of the BGCWM. However, the coverage area of the BGCWM was increased slightly without the force of the tidal harmonics. When the model was driven by the monthly averaged surface forcing, the circulation structure was changed to some extent, and the coverage area of the BGCWM almost extended outwards 100%, implying the circulation and water mass in the Beibu Gulf had strong responses to the temporal resolution of the surface forces.

Observed water current and transport through Qiongzhou Strait during August 2010

The velocity structure of the residual current across an entire section of the Qiongzhou Strait (QS) in summer is presented for the first time. Shipboard Acoustic Doppler Current Profile measurements, from the mid-region of the QS (110.18°E), were collected on 1–4 August 2010. The diurnal tidal currents had their maximum amplitudes between 4.24 and 20.24 m. Their amplitude along the major axis ranged from approximately 0.55 m/s in the middle part of the strait (20.15°N) to 0.84 m/s in the north part of the strait (20.20°N). Both anticlockwise and clockwise tidal current rotations exist in the QS. During the observation period (neap tide), a significant westward residual current occupied almost the entire study section. Two velocity cores of westward current were observed at the northern part and near the deepest trough, although an eastward current appeared in the middle part of the transect. The deepest core was located near 62 m at 20.13°N, with a maximum velocity of −0.34 m/s. The shallower core was located at approximately 16 m at 20.20°N, with a maximum velocity of −0.33 m/s. The estimated total volume of water transported through the QS was −0.16 Sv. This value is an important boundary condition, applicable to numerical models studying coastal ocean circulation in the northwestern South China Sea.

Effects of tropical cyclones on large-scale circulation and ocean heat transport in the South China Sea

In this study, we investigate the influence of tropical cyclones (TCs) on large-scale circulation and ocean heat transport in the South China Sea (SCS) by using an ocean general circulation model at a 1/8° resolution during 2000–2008. The model uses a data assimilation system to assimilate observations in order to improve the representation of SCS circulation. The results reveal an unexpected deep SCS circulation anomaly induced by TCs, which suggests that effects of TC can penetrate deeper into the ocean. This deep effect may result from the near inertial oscillations excited by TCs. The inertial oscillations can propagate downward to the oceanic interior. The analyses confirm that TCs have two effects on ocean heat transport of the SCS. Firstly, the wind stress curl induced by TCs affects the structure of SCS circulation, and then changes heat transport. Secondly, TCs pump surface heat downward to the thermocline, increasing the heat injection from the atmosphere to the ocean. Two effects together amplify the outflow of the surface heat southward away the SCS through the Mindoro and Karimata Straits. The TC-induced heat transports through the Mindoro, Balabac and Karimata Straits account for 20 % of the total heat transport through three straits. An implication of this study is that ocean models need to simulate the TC effect on heat transport in order to correctly evaluate the role of the SCS through flow in regulating upper ocean circulation and climate in the Indonesian maritime continent and its adjacent regions.

Intermonsoon Variation of Physical Characteristics and Current Circulation along the East Coast of Peninsular Malaysia

Data from eight cruises spanning from 2002 to 2007 are used to investigate the seasonal changes in water characteristics and current circulation in southern South China Sea along the East Coast of Peninsular Malaysia. The surveys were made during two intermonsoon periods which are during March/April and September/October. In addition, monthly sea surface temperature from Moderate Resolution Imaging Spectroradiometer (MODIS) is used to provide wider coverage of spatial and temporal for seasonality study. Overall, the area shares different physical properties between the two seasons. During September/October temperature is lower and salinity is higher compared to the data during Mac/April/May. The current along the East Coast of Peninsular Malaysia also shows seasonality, with dominant current flow southward during Mac/April and northward during September/October.

Impacts of the Madden–Julian Oscillation on the Summer South China Sea Ocean Circulation and Temperature

Abstract The present study investigates the impact of the Madden–Julian oscillation (MJO) on the South China Sea (SCS) in summer with three types of models: a theoretical Sverdrup model, a 1.5-layer reduced gravity model, and a regional ocean model [Regional Ocean Modeling System (ROMS)]. Results show that the ocean circulation in the SCS has an intraseasonal oscillation responding to the MJO. During its westerly phase, the MJO produces positive (negative) wind stress curl over the northern (southern) SCS and thus induces an enhanced cyclonic (anticyclonic) circulation in the northern (southern) SCS. This not only cools sea surface temperature (SST) but also decreases (increases) subsurface temperature in the northern (southern) SCS. During its easterly phase, the MJO basically produces a reversed but weaker influence on SCS ocean circulation and temperature. Thus, the MJO can have an imprint on the summer climatology of SCS circulation and temperature. The authors' analysis further indicates that the MJO's dynamic effect associated with wind is generally more important than its thermodynamic effect in modulating the regional ocean circulation and temperature. The present study suggests that the MJO is important for summer ocean circulation and temperature in the SCS.

The seasonal variation of the upper layers of the South China Sea (SCS) circulation and the Indonesian through flow (ITF): An ocean model study

The upper layer, wind-driven circulation of the South China Sea (SCS), its through-flow (SCSTF) and the Indonesian through flow (ITF) are simulated using a high resolution model, FVCOM (finite volume coastal ocean model) in a regional domain comprising the Maritime Continent. The regional model is embedded in the MIT global ocean general circulation model (ogcm) which provides surface forcing and boundary conditions of all the oceanographic variables at the lateral open boundaries in the Pacific and Indian oceans. A five decade long simulation is available from the MITgcm and we choose to investigate and compare the climatologies of two decades, 1960–1969 and 1990–1999.The seasonal variability of the wind-driven circulation produced by the monsoon system is realistically simulated. In the SCS the dominant driving force is the monsoon wind and the surface circulation reverses accordingly, with a net cyclonic tendency in winter and anticyclonic in summer. The SCS circulation in the 90s is weaker than in the 60s because of the weaker monsoon system in the 90s. In the upper 50m the interaction between the SCSTF and ITF is very important. The southward ITF can be blocked by the SCSTF at the Makassar Strait during winter. In summer, part of the ITF feeds the SCSTF flowing into the SCS through the Karimata Strait. Differently from the SCS, the ITF is primarily controlled by the sea level difference between the western Pacific and eastern Indian Ocean. The ITF flow, consistently southwestward below the surface layer, is stronger in the 90s.The volume transports for winter, summer and yearly are estimated from the simulation through all the interocean straits. On the annual average, there is a ∼5.6Sv of western Pacific water entering the SCS through the Luzon Strait and ∼1.4Sv exiting through the Karimata Strait into the Java Sea. Also, ∼2Sv of SCS water enters the Sulu Sea through the Mindoro Strait, while ∼2.9Sv flow southwards through the Sibutu Strait merging into the ITF. The ITF inflow occurs through the Makassar Strait (up to ∼62%) and the Lifamatola Strait (∼38%). The annual average volume transport of the ITF inflow from the simulation is ∼15Sv in the 60s and ∼16.6Sv in the 90s, very close to the long term observations. The ITF outflow through the Lombok, Ombai and Timor straits is ∼16.8Sv in the 60s and 18.9Sv in the 90s, with the outflow greater by 1.7Sv and 2.3Sv respectively. The transport estimates of the simulation at all the straits are in rather good agreement with the observational estimates.We analyze the thermal structure of the domain in the 60s and 90s and assess the simulated temperature patterns against the SODA reanalysis product, with special focus on the shallow region of the SCS. The SODA dataset clearly shows that the yearly averaged temperatures of the 90s are overall warmer than those of the 60s in the surface, intermediate and some of the deep layers and the decadal differences (90s−60s) indicate that the overall warming of the SCS interior is a local effect. In the simulation the warm trend from the 60s to the 90s in well reproduced in the surface layer. In particular, the simulated temperature profiles at two shallow sites at midway in the SCSTF agree rather well with the SODA profiles. However, the warming trend in the intermediate (deep) layers is not reproduced in the simulation. We find that this deficiency is mostly due to a deficiency in the initial temperature fields provide by the MITgcm.