The structure and variability of the Halmahera Mindanao Eddies (HE ME), which are thought to be quasi‐stationary eddies, described based on onboard time‐series observations in gateway region Indonesian Throughflow (ITF). HE was found have a clear anticyclonic eddy during all cruises. It tilted northward and/or westward with increasing depth. mixes waters from northern southern hemispheres transfers this mixed water eastern route ITF. shifted northwestward boreal summer cold phase ENSO (El...

Subthermocline circulation in the tropical North Pacific Ocean (2°N–30°N) is investigated using profiling float temperature‐salinity data from International Argo and Origins of Kuroshio Mindanao Current (OKMC) projects. Three well‐defined eastward jets are detected beneath wind‐driven, westward flowing Equatorial Current. Dubbed Undercurrent (NEUC) jets, these subthermocline have a typical core velocity 2–5 cms −1 spatially coherent western boundary to about 120°W across basin. Centered...

Intraseasonal oscillations in sea level, surface temperature, and upper ocean flow field have recently been observed various locations surrounding the Indonesian seas. While at these similar wave periods ranging from 30 to 85 days, their forcing mechanisms can involve different dynamic processes. In order clarify processes essential for intraseasonal signals, authors adopted this study a fine-resolution 1½-layer reduced-gravity model carried out series of experiments by varying coastline...

Current variability at the Pacific entrance of Indonesian Throughflow is investigated using direct current and hydrographic measurements. Two moorings with three meters (depths 350, 550, 1050 m) one conductivity‐temperature‐depth profiler (260 were deployed 4°1′N, 127°31′E 3°11′N, 128°27′E between Talaud Islands Morotai Island (Indonesia) from February 1994 to June 1995. Data four surveys conducted mainly Mindanao New Guinea 1996 are also used. The onset a strong northwestward flow was...

Seasonal and interannual variations of the New Guinea Coastal Current (NGCC) Undercurrent (NGCUC) were investigated by examining 5 years' data from acoustic Doppler current profiler moorings at two sites (2°S 142°E, 2.5°S 142°E) off coast. The NGCC flowed northwestward as is usual intensified during boreal summer, then weakened or even reversed direction to southeastward winter. This seasonal change correlated monsoonal wind variation. However, 1997–1998 El Niño, winter was not observed,...

Water masses between Mindanao and New Guinea are investigated, using hydrographic data, during two R/V Kaiyo World Ocean Circulation Experiment cruises conducted in October 1992 February 1994. The analysis of this data indicates that the South Pacific Tropical (SPTW), which is formed southern hemisphere, reached area Morotai Island farther north Antarctic Intermediate (AAIW) exists southwestern southernmost Philippine Sea. There northeastward flow Talaud Islands Island, probably a part...

Mooring observations were conducted from October 1999 to July 2002 near the east coast of Mindanao Island, Philippines, (6°50′N, 126°43′E) observe current variability at axis Current (MC). The MC was a strong with subsurface velocity maximum exceeding 1.3 m s −1 approximately 100 depth. flows shallower than 700 m, and there no evidence steady northward (the Undercurrent) study location. Compared large average velocity, low (standard deviation <0.2 for all directions). All observed...

Abstract Ocean variations at semiannual, annual, and interannual time scales in the Mindanao Dome (MD) region of southern Philippine Sea were examined using data derived from underwater sensors on Triangle Trans-Ocean Buoy Network (TRITON) buoys 8°N, 137°E; 5°N, 130°E. Annual signal dominated above 300-m depth MD region. At 137°E, saline water exceeding 35 psu was observed 100–200-m boreal winter to spring, seemingly associated with meridional migration North Equatorial Countercurrent during...

Abstract Subthermocline western boundary circulation along the low-latitude North Pacific Ocean (2°–25°N) is investigated by using profiling float and historical CTD/expendable CTD (XCTD) data analyzing an eddy-resolving global OGCM output. In contrast to existing paradigm depicting it as a reversed pattern of wind-driven above ventilated thermocline (i.e., depth < 26.8 σ θ ), subthermocline found comprise two components governed distinct dynamical processes. For meridional scales shorter...

Analysis of altimeter data combined with results from a high‐resolution general circulation model has revealed the existence semiannual variation in western tropical Pacific. The cannot be explained by local Ekman pumping alone, but is also related to westward propagation Rossby waves originating central Pacific, corresponding northern hemisphere Inter‐Tropical Convergence Zone and southern South Pacific Zone. This signal intensifies toward boundary appears have notable impact on there. In...

High vertical resolution measurements of the flow in western equatorial Pacific reveal shear to be dominated by features that have a small scale (O(10 m)). This is true for all we taken over 3 year period and differing ENSO states. Much measured turbulent activity found associated with these features, suggestion mixing region heavily influenced presence this activity. The level within above thermocline strongly modulated events, being significantly greater during observed La Niña event....

Upper ocean currents in the Celebes Sea, northern Maluku and adjacent region to east were measured during February 1999 using a shipboard acoustic Doppler current profiler (ADCP) on R/V Kaiyo. The new data provide first quasisynoptic observations of circulation within central Sea. South Mindanao, Mindanao Current split into three branches. Only westernmost branch entered where part retroflected around cyclonic eddy western Sea took shorter route through eastern basin before two paths joined...

Under the auspices of World Ocean Circulation Experiment (WOCE) Hydrographic Program, Japan carried out a total four sections in North Pacific, P2 at 30°N, P13 165°E, P9 137°E, and P8 130°E. These Japanese several other WOCE are used to estimate transport Pacific Intermediate Water (NPIW) subtropical gyre. Previous studies speculate about 3 Sv (1 = 10 6 m s −1 ) NPIW transport, originating mainly Okhotsk Sea, entering gyre southward via mixed water region east Japan. The subpolar input is...

Abstract Two subsurface moorings were deployed east of Mindanao Island, the Philippines, at 7°01′N, 126°55′E and 127°46′E, location inshore offshore cores Undercurrent (MUC) suggested by past studies, from September 2011 to October 2012 March 2013. A steady northward undercurrent, MUC, was not confirmed these observations, only its core but also core. The observed mean flow mooring sites seems be part an anticyclonic eddy rather than MUC. particle‐tracking experiment using a high‐resolution...

A better understanding of variability in the volume warm water equatorial Pacific pycnocline (warm volume, or WWV) is critical to El Niño‐Southern Oscillation (ENSO) variability. We have investigated meridional WWV transport Northern (NH) and Southern Hemispheres (SH) using a high‐resolution general circulation model. The western boundary region compensates interior SH, where Sverdrup balance holds approximately. In contrast, such compensation does not hold NH, because lags by about 7...

Abstract We investigate the characteristics of shear‐generated turbulence in natural environment by considering data from a number cruises western equatorial Pacific. In this region, vertical shear flow is dominated structures that have relatively small scale O(10 m). Combining all cruises, we find strong relationship between turbulent dissipation rate, ϵ , shear, S and buoyancy frequency, N . Examination at fixed value Richardson number, Ri = 2 ∕ shows for wide range values where u t an...

We analyzed 3-hourly Tropical Rainfall Measuring Mission multi-satellite analysis (TRMM 3B42) version-7 data for the 17-year period 1998-2014 to investigate seasonal and geographic characteristics of diurnal rainfall cycle (DRC) over Sumatera, Indonesia. Dividing Sumatera into north, central, south regions approximately perpendicular west coast, we point out first time early-afternoon initiation daily not only in Barisan Mountains but also east-coastal small islands (ECSIs) such as Bangka...

We analyzed the results of a high‐resolution global ocean circulation model with 1/4‐degree grid spacing and 55 vertical levels to investigate structure mechanism subsurface countercurrents (SCCs) in equatorial Pacific Ocean. The SCCs have observably similar structures; that is, they are associated pycnostad between 26.0 26.8σ θ , deep west shallow east, densities SCCs' cores decrease from east. volume transport density layer shows each north SCC primary south accompanies westward current at...